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authorPeter Dettman <peter.dettman@bouncycastle.org>2018-07-08 16:30:26 +0700
committerPeter Dettman <peter.dettman@bouncycastle.org>2018-07-08 16:30:26 +0700
commit5268ce495106a67a3e167559b78c6dc1f857a423 (patch)
tree1b18df57d8e9dd6cf327f53608f9d1e228711332
parentImproved performance for BigInteger.ToString(int) (diff)
downloadBouncyCastle.NET-ed25519-5268ce495106a67a3e167559b78c6dc1f857a423.tar.xz
Add Ed25519 and Ed448 from RFC 8032
-rw-r--r--crypto/BouncyCastle.Android.csproj8
-rw-r--r--crypto/BouncyCastle.csproj8
-rw-r--r--crypto/BouncyCastle.iOS.csproj8
-rw-r--r--crypto/Readme.html1
-rw-r--r--crypto/crypto.csproj20
-rw-r--r--crypto/src/math/ec/rfc7748/X25519.cs4
-rw-r--r--crypto/src/math/ec/rfc7748/X25519Field.cs147
-rw-r--r--crypto/src/math/ec/rfc7748/X448.cs8
-rw-r--r--crypto/src/math/ec/rfc7748/X448Field.cs123
-rw-r--r--crypto/src/math/ec/rfc8032/Ed25519.cs937
-rw-r--r--crypto/src/math/ec/rfc8032/Ed448.cs1067
-rw-r--r--crypto/src/math/raw/Interleave.cs71
-rw-r--r--crypto/src/math/raw/Nat.cs85
-rw-r--r--crypto/test/UnitTests.csproj2
-rw-r--r--crypto/test/src/math/ec/rfc8032/test/Ed25519Test.cs231
-rw-r--r--crypto/test/src/math/ec/rfc8032/test/Ed448Test.cs400
16 files changed, 3078 insertions, 42 deletions
diff --git a/crypto/BouncyCastle.Android.csproj b/crypto/BouncyCastle.Android.csproj
index cdb80981b..d6f9b737c 100644
--- a/crypto/BouncyCastle.Android.csproj
+++ b/crypto/BouncyCastle.Android.csproj
@@ -1273,9 +1273,11 @@
     <Compile Include="src\math\ec\multiplier\ZSignedDigitL2RMultiplier.cs" />
     <Compile Include="src\math\ec\multiplier\ZSignedDigitR2LMultiplier.cs" />
     <Compile Include="src\math\ec\rfc7748\X25519.cs" />
-    <Compile Include="src\math\ec\rfc7748\X25519Field.cs"/>
-    <Compile Include="src\math\ec\rfc7748\X448.cs"/>
-    <Compile Include="src\math\ec\rfc7748\X448Field.cs"/>
+    <Compile Include="src\math\ec\rfc7748\X25519Field.cs" />
+    <Compile Include="src\math\ec\rfc7748\X448.cs" />
+    <Compile Include="src\math\ec\rfc7748\X448Field.cs" />
+    <Compile Include="src\math\ec\rfc8032\Ed25519.cs" />
+    <Compile Include="src\math\ec\rfc8032\Ed448.cs" />
     <Compile Include="src\math\field\FiniteFields.cs" />
     <Compile Include="src\math\field\GF2Polynomial.cs" />
     <Compile Include="src\math\field\GenericPolynomialExtensionField.cs" />
diff --git a/crypto/BouncyCastle.csproj b/crypto/BouncyCastle.csproj
index ab36fa529..679e226d0 100644
--- a/crypto/BouncyCastle.csproj
+++ b/crypto/BouncyCastle.csproj
@@ -1267,9 +1267,11 @@
     <Compile Include="src\math\ec\multiplier\ZSignedDigitL2RMultiplier.cs" />
     <Compile Include="src\math\ec\multiplier\ZSignedDigitR2LMultiplier.cs" />
     <Compile Include="src\math\ec\rfc7748\X25519.cs" />
-    <Compile Include="src\math\ec\rfc7748\X25519Field.cs"/>
-    <Compile Include="src\math\ec\rfc7748\X448.cs"/>
-    <Compile Include="src\math\ec\rfc7748\X448Field.cs"/>
+    <Compile Include="src\math\ec\rfc7748\X25519Field.cs" />
+    <Compile Include="src\math\ec\rfc7748\X448.cs" />
+    <Compile Include="src\math\ec\rfc7748\X448Field.cs" />
+    <Compile Include="src\math\ec\rfc8032\Ed25519.cs" />
+    <Compile Include="src\math\ec\rfc8032\Ed448.cs" />
     <Compile Include="src\math\field\FiniteFields.cs" />
     <Compile Include="src\math\field\GF2Polynomial.cs" />
     <Compile Include="src\math\field\GenericPolynomialExtensionField.cs" />
diff --git a/crypto/BouncyCastle.iOS.csproj b/crypto/BouncyCastle.iOS.csproj
index 49a81078e..1d3616d05 100644
--- a/crypto/BouncyCastle.iOS.csproj
+++ b/crypto/BouncyCastle.iOS.csproj
@@ -1268,9 +1268,11 @@
     <Compile Include="src\math\ec\multiplier\ZSignedDigitL2RMultiplier.cs" />
     <Compile Include="src\math\ec\multiplier\ZSignedDigitR2LMultiplier.cs" />
     <Compile Include="src\math\ec\rfc7748\X25519.cs" />
-    <Compile Include="src\math\ec\rfc7748\X25519Field.cs"/>
-    <Compile Include="src\math\ec\rfc7748\X448.cs"/>
-    <Compile Include="src\math\ec\rfc7748\X448Field.cs"/>
+    <Compile Include="src\math\ec\rfc7748\X25519Field.cs" />
+    <Compile Include="src\math\ec\rfc7748\X448.cs" />
+    <Compile Include="src\math\ec\rfc7748\X448Field.cs" />
+    <Compile Include="src\math\ec\rfc8032\Ed25519.cs" />
+    <Compile Include="src\math\ec\rfc8032\Ed448.cs" />
     <Compile Include="src\math\field\FiniteFields.cs" />
     <Compile Include="src\math\field\GF2Polynomial.cs" />
     <Compile Include="src\math\field\GenericPolynomialExtensionField.cs" />
diff --git a/crypto/Readme.html b/crypto/Readme.html
index c05560d93..9f4705f00 100644
--- a/crypto/Readme.html
+++ b/crypto/Readme.html
@@ -301,6 +301,7 @@ We state, where EC MQV has not otherwise been disabled or removed:
             <li>Further work has been done on improving SHA-3 performance.</li>
             <li>EC key generation and signing now use cache-timing resistant table lookups.</li>
             <li>RFC 7748: Added low-level implementations of X25519 and X448.</li>
+            <li>RFC 8032: Added low-level implementations of Ed25519 and Ed448.</li>
         </ul>
         <h5>Additional Notes</h5>
         <ul>
diff --git a/crypto/crypto.csproj b/crypto/crypto.csproj
index d0afb9f14..e6f092c1e 100644
--- a/crypto/crypto.csproj
+++ b/crypto/crypto.csproj
@@ -6239,6 +6239,16 @@
                     BuildAction = "Compile"
                 />
                 <File
+                    RelPath = "src\math\ec\rfc8032\Ed25519.cs"
+                    SubType = "Code"
+                    BuildAction = "Compile"
+                />
+                <File
+                    RelPath = "src\math\ec\rfc8032\Ed448.cs"
+                    SubType = "Code"
+                    BuildAction = "Compile"
+                />
+                <File
                     RelPath = "src\math\field\FiniteFields.cs"
                     SubType = "Code"
                     BuildAction = "Compile"
@@ -12340,6 +12350,16 @@
                     BuildAction = "Compile"
                 />
                 <File
+                    RelPath = "test\src\math\ec\rfc8032\test\Ed25519Test.cs"
+                    SubType = "Code"
+                    BuildAction = "Compile"
+                />
+                <File
+                    RelPath = "test\src\math\ec\rfc8032\test\Ed448Test.cs"
+                    SubType = "Code"
+                    BuildAction = "Compile"
+                />
+                <File
                     RelPath = "test\src\math\ec\test\AllTests.cs"
                     SubType = "Code"
                     BuildAction = "Compile"
diff --git a/crypto/src/math/ec/rfc7748/X25519.cs b/crypto/src/math/ec/rfc7748/X25519.cs
index 16f680d90..a10d53da5 100644
--- a/crypto/src/math/ec/rfc7748/X25519.cs
+++ b/crypto/src/math/ec/rfc7748/X25519.cs
@@ -10,10 +10,10 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
         private const int C_A24 = (C_A + 2)/4;
 
         // 0x1
-        //private static readonly int[] S_x = new int[] { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+        //private static readonly int[] S_x = { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
 
         // 0x215132111D8354CB52385F46DCA2B71D440F6A51EB4D1207816B1E0137D48290
-        private static readonly int[] PsubS_x = new int[]{ 0x03D48290, 0x02C7804D, 0x01207816, 0x028F5A68, 0x00881ED4, 0x00A2B71D,
+        private static readonly int[] PsubS_x = { 0x03D48290, 0x02C7804D, 0x01207816, 0x028F5A68, 0x00881ED4, 0x00A2B71D,
             0x0217D1B7, 0x014CB523, 0x0088EC1A, 0x0042A264 };
 
         private static int[] precompBase = null;
diff --git a/crypto/src/math/ec/rfc7748/X25519Field.cs b/crypto/src/math/ec/rfc7748/X25519Field.cs
index 282f41628..fd5599657 100644
--- a/crypto/src/math/ec/rfc7748/X25519Field.cs
+++ b/crypto/src/math/ec/rfc7748/X25519Field.cs
@@ -11,6 +11,9 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
         private const int M25 = 0x01FFFFFF;
         private const int M26 = 0x03FFFFFF;
 
+        private static readonly int[] RootNegOne = { 0x020EA0B0, 0x0386C9D2, 0x00478C4E, 0x0035697F, 0x005E8630,
+            0x01FBD7A7, 0x0340264F, 0x01F0B2B4, 0x00027E0E, 0x00570649 };
+
         private X25519Field() {}
 
         public static void Add(int[] x, int[] y, int[] z)
@@ -21,6 +24,16 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             }
         }
 
+        public static void AddOne(int[] z)
+        {
+            z[0] += 1;
+        }
+
+        public static void AddOne(int[] z, int zOff)
+        {
+            z[zOff] += 1;
+        }
+
         public static void Apm(int[] x, int[] y, int[] zp, int[] zm)
         {
             for (int i = 0; i < Size; ++i)
@@ -54,6 +67,17 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             z[5] = z5; z[6] = z6; z[7] = z7; z[8] = z8; z[9] = z9;
         }
 
+        public static void CNegate(int negate, int[] z)
+        {
+            Debug.Assert(negate >> 1 == 0);
+
+            int mask = 0 - negate;
+            for (int i = 0; i < Size; ++i)
+            {
+                z[i] = (z[i] ^ mask) - mask;
+            }
+        }
+
         public static void Copy(int[] x, int xOff, int[] z, int zOff)
         {
             for (int i = 0; i < Size; ++i)
@@ -67,6 +91,11 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             return new int[Size];
         }
 
+        public static int[] CreateTable(int n)
+        {
+            return new int[Size * n];
+        }
+
         public static void CSwap(int swap, int[] a, int[] b)
         {
             Debug.Assert(swap >> 1 == 0);
@@ -143,24 +172,23 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             // (250 1s) (1 0s) (1 1s) (1 0s) (2 1s)
             // Addition chain: [1] [2] 3 5 10 15 25 50 75 125 [250]
 
-            int[] x2 = Create();    Sqr(x, x2);             Mul(x, x2, x2);
-            int[] x3 = Create();    Sqr(x2, x3);            Mul(x, x3, x3);
-            int[] x5 = x3;          Sqr(x3, 2, x5);         Mul(x2, x5, x5);
-            int[] x10 = Create();   Sqr(x5, 5, x10);        Mul(x5, x10, x10);
-            int[] x15 = Create();   Sqr(x10, 5, x15);       Mul(x5, x15, x15);
-            int[] x25 = x5;         Sqr(x15, 10, x25);      Mul(x10, x25, x25);
-            int[] x50 = x10;        Sqr(x25, 25, x50);      Mul(x25, x50, x50);
-            int[] x75 = x15;        Sqr(x50, 25, x75);      Mul(x25, x75, x75);
-            int[] x125 = x25;       Sqr(x75, 50, x125);     Mul(x50, x125, x125);
-            int[] x250 = x50;       Sqr(x125, 125, x250);   Mul(x125, x250, x250);
-
-            int[] t = x125;
-            Sqr(x250, 2, t);
-            Mul(t, x, t);
+            int[] x2 = Create();
+            int[] t = Create();
+            PowPm5d8(x, x2, t);
             Sqr(t, 3, t);
             Mul(t, x2, z);
         }
 
+        public static bool IsZeroVar(int[] x)
+        {
+            int d = 0;
+            for (int i = 0; i < Size; ++i)
+            {
+                d |= x[i];
+            }
+            return d == 0;
+        }
+
         public static void Mul(int[] x, int y, int[] z)
         {
             int x0 = x[0], x1 = x[1], x2 = x[2], x3 = x[3], x4 = x[4];
@@ -345,6 +373,14 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             z[9]     = z9 + (int)t;
         }
 
+        public static void Negate(int[] x, int[] z)
+        {
+            for (int i = 0; i < Size; ++i)
+            {
+                z[i] = -x[i];
+            }
+        }
+
         public static void Normalize(int[] z)
         {
             int x = (z[9] >> 23) & 1;
@@ -353,6 +389,37 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             Debug.Assert(z[9] >> 24 == 0);
         }
 
+        public static void One(int[] z)
+        {
+            z[0] = 1;
+            for (int i = 1; i < Size; ++i)
+            {
+                z[i] = 0;
+            }
+        }
+
+        private static void PowPm5d8(int[] x, int[] rx2, int[] rz)
+        {
+            // z = x^((p-5)/8) = x^FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFD
+            // (250 1s) (1 0s) (1 1s)
+            // Addition chain: [1] 2 3 5 10 15 25 50 75 125 [250]
+
+            int[] x2 = rx2;         Sqr(x, x2);             Mul(x, x2, x2);
+            int[] x3 = Create();    Sqr(x2, x3);            Mul(x, x3, x3);
+            int[] x5 = x3;          Sqr(x3, 2, x5);         Mul(x2, x5, x5);
+            int[] x10 = Create();   Sqr(x5, 5, x10);        Mul(x5, x10, x10);
+            int[] x15 = Create();   Sqr(x10, 5, x15);       Mul(x5, x15, x15);
+            int[] x25 = x5;         Sqr(x15, 10, x25);      Mul(x10, x25, x25);
+            int[] x50 = x10;        Sqr(x25, 25, x50);      Mul(x25, x50, x50);
+            int[] x75 = x15;        Sqr(x50, 25, x75);      Mul(x25, x75, x75);
+            int[] x125 = x25;       Sqr(x75, 50, x125);     Mul(x50, x125, x125);
+            int[] x250 = x50;       Sqr(x125, 125, x250);   Mul(x125, x250, x250);
+
+            int[] t = x125;
+            Sqr(x250, 2, t);
+            Mul(t, x, rz);
+        }
+
         private static void Reduce(int[] z, int c)
         {
             int z9 = z[9], t = z9;
@@ -509,6 +576,45 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             }
         }
 
+        public static bool SqrtRatioVar(int[] u, int[] v, int[] z)
+        {
+            int[] uv3 = Create();
+            int[] uv7 = Create();
+
+            Mul(u, v, uv3);
+            Sqr(v, uv7);
+            Mul(uv3, uv7, uv3);
+            Sqr(uv7, uv7);
+            Mul(uv7, uv3, uv7);
+
+            int[] t = Create();
+            int[] x = Create();
+            PowPm5d8(uv7, t, x);
+            Mul(x, uv3, x);
+
+            int[] vx2 = Create();
+            Sqr(x, vx2);
+            Mul(vx2, v, vx2);
+
+            Sub(vx2, u, t);
+            Normalize(t);
+            if (IsZeroVar(t))
+            {
+                Copy(x, 0, z, 0);
+                return true;
+            }
+
+            Add(vx2, u, t);
+            Normalize(t);
+            if (IsZeroVar(t))
+            {
+                Mul(x, RootNegOne, z);
+                return true;
+            }
+
+            return false;
+        }
+
         public static void Sub(int[] x, int[] y, int[] z)
         {
             for (int i = 0; i < Size; ++i)
@@ -516,5 +622,18 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
                 z[i] = x[i] - y[i];
             }
         }
+
+        public static void SubOne(int[] z)
+        {
+            z[0] -= 1;
+        }
+
+        public static void Zero(int[] z)
+        {
+            for (int i = 0; i < Size; ++i)
+            {
+                z[i] = 0;
+            }
+        }
     }
 }
diff --git a/crypto/src/math/ec/rfc7748/X448.cs b/crypto/src/math/ec/rfc7748/X448.cs
index 32a4a9e2a..88e8a5d76 100644
--- a/crypto/src/math/ec/rfc7748/X448.cs
+++ b/crypto/src/math/ec/rfc7748/X448.cs
@@ -10,14 +10,14 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
         private const uint C_A24 = (C_A + 2)/4;
 
         // 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFE
-        private static readonly uint[] S_x = new uint[]{ 0x0FFFFFFEU, 0x0FFFFFFFU, 0x0FFFFFFFU, 0x0FFFFFFFU, 0x0FFFFFFFU, 0x0FFFFFFFU,
+        private static readonly uint[] S_x = { 0x0FFFFFFEU, 0x0FFFFFFFU, 0x0FFFFFFFU, 0x0FFFFFFFU, 0x0FFFFFFFU, 0x0FFFFFFFU,
             0x0FFFFFFFU, 0x0FFFFFFFU, 0x0FFFFFFEU, 0x0FFFFFFFU, 0x0FFFFFFFU, 0x0FFFFFFFU, 0x0FFFFFFFU, 0x0FFFFFFFU, 0x0FFFFFFFU,
             0x0FFFFFFFU };
 
         // 0xF0FAB725013244423ACF03881AFFEB7BDACDD1031C81B9672954459D84C1F823F1BD65643ACE1B5123AC33FF1C69BAF8ACB1197DC99D2720
-        private static readonly uint[] PsubS_x = new uint[]{ 0x099d2720U, 0x0b1197dcU, 0x09baf8acU, 0x033ff1c6U, 0x0b5123acU,
-            0x0643ace1U, 0x03f1bd65U, 0x084c1f82U, 0x0954459dU, 0x081b9672U, 0x0dd1031cU, 0x0eb7bdacU, 0x03881affU, 0x0423acf0U,
-            0x05013244U, 0x0f0fab72U };
+        private static readonly uint[] PsubS_x = { 0x099D2720U, 0x0B1197DCU, 0x09BAF8ACU, 0x033FF1C6U, 0x0B5123ACU,
+            0x0643ACE1U, 0x03F1BD65U, 0x084C1F82U, 0x0954459DU, 0x081B9672U, 0x0DD1031CU, 0x0EB7BDACU, 0x03881AFFU, 0x0423ACF0U,
+            0x05013244U, 0x0F0FAB72U };
 
         private static uint[] precompBase = null;
 
diff --git a/crypto/src/math/ec/rfc7748/X448Field.cs b/crypto/src/math/ec/rfc7748/X448Field.cs
index 0c44f1eb5..5a682714d 100644
--- a/crypto/src/math/ec/rfc7748/X448Field.cs
+++ b/crypto/src/math/ec/rfc7748/X448Field.cs
@@ -1,6 +1,8 @@
 using System;
 using System.Diagnostics;
 
+using Org.BouncyCastle.Math.Raw;
+
 namespace Org.BouncyCastle.Math.EC.Rfc7748
 {
     [CLSCompliantAttribute(false)]
@@ -20,6 +22,16 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             }
         }
 
+        public static void AddOne(uint[] z)
+        {
+            z[0] += 1;
+        }
+
+        public static void AddOne(uint[] z, int zOff)
+        {
+            z[zOff] += 1;
+        }
+
         //public static void Apm(int[] x, int[] y, int[] zp, int[] zm)
         //{
         //    for (int i = 0; i < Size; ++i)
@@ -62,6 +74,16 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             z[8] = z8; z[9] = z9; z[10] = z10; z[11] = z11; z[12] = z12; z[13] = z13; z[14] = z14; z[15] = z15;
         }
 
+        public static void CNegate(int negate, uint[] z)
+        {
+            Debug.Assert(negate >> 1 == 0);
+
+            uint[] t = Create();
+            Sub(t, z, t);
+
+            Nat.CMov(Size, negate, t, 0, z, 0);
+        }
+
         public static void Copy(uint[] x, int xOff, uint[] z, int zOff)
         {
             for (int i = 0; i < Size; ++i)
@@ -166,25 +188,23 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             // z = x^(p-2) = x^(2^448 - 2^224 - 3)
             // (223 1s) (1 0s) (222 1s) (1 0s) (1 1s)
             // Addition chain: [1] 2 3 6 9 18 19 37 74 111 [222] [223]
-            uint[] x2 = Create();    Sqr(x, x2);             Mul(x, x2, x2);
-            uint[] x3 = Create();    Sqr(x2, x3);            Mul(x, x3, x3);
-            uint[] x6 = Create();    Sqr(x3, 3, x6);         Mul(x3, x6, x6);
-            uint[] x9 = Create();    Sqr(x6, 3, x9);         Mul(x3, x9, x9);
-            uint[] x18 = Create();   Sqr(x9, 9, x18);        Mul(x9, x18, x18);
-            uint[] x19 = Create();   Sqr(x18, x19);          Mul(x, x19, x19);
-            uint[] x37 = Create();   Sqr(x19, 18, x37);      Mul(x18, x37, x37);
-            uint[] x74 = Create();   Sqr(x37, 37, x74);      Mul(x37, x74, x74);
-            uint[] x111 = Create();  Sqr(x74, 37, x111);     Mul(x37, x111, x111);
-            uint[] x222 = Create();  Sqr(x111, 111, x222);   Mul(x111, x222, x222);
-            uint[] x223 = Create();  Sqr(x222, x223);        Mul(x, x223, x223);
 
             uint[] t = Create();
-            Sqr(x223, 223, t);
-            Mul(t, x222, t);
+            PowPm3d4(x, t);
             Sqr(t, 2, t);
             Mul(t, x, z);
         }
 
+        public static bool IsZeroVar(uint[] x)
+        {
+            uint d = 0;
+            for (int i = 0; i < Size; ++i)
+            {
+                d |= x[i];
+            }
+            return d == 0U;
+        }
+
         public static void Mul(uint[] x, uint y, uint[] z)
         {
             uint x0 = x[0], x1 = x[1], x2 = x[2], x3 = x[3], x4 = x[4], x5 = x[5], x6 = x[6], x7 = x[7];
@@ -563,6 +583,12 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             z[15] = z15;
         }
 
+        public static void Negate(uint[] x, uint[] z)
+        {
+            uint[] zero = Create();
+            Sub(zero, x, z);
+        }
+
         public static void Normalize(uint[] z)
         {
             //int x = (z[15] >> (28 - 1)) & 1;
@@ -571,6 +597,37 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             Debug.Assert(z[15] >> 28 == 0U);
         }
 
+        public static void One(uint[] z)
+        {
+            z[0] = 1U;
+            for (int i = 1; i < Size; ++i)
+            {
+                z[i] = 0;
+            }
+        }
+
+        private static void PowPm3d4(uint[] x, uint[] z)
+        {
+            // z = x^((p-3)/4) = x^(2^446 - 2^222 - 1)
+            // (223 1s) (1 0s) (222 1s)
+            // Addition chain: 1 2 3 6 9 18 19 37 74 111 [222] [223]
+            uint[] x2 = Create();   Sqr(x, x2);             Mul(x, x2, x2);
+            uint[] x3 = Create();   Sqr(x2, x3);            Mul(x, x3, x3);
+            uint[] x6 = Create();   Sqr(x3, 3, x6);         Mul(x3, x6, x6);
+            uint[] x9 = Create();   Sqr(x6, 3, x9);         Mul(x3, x9, x9);
+            uint[] x18 = Create();  Sqr(x9, 9, x18);        Mul(x9, x18, x18);
+            uint[] x19 = Create();  Sqr(x18, x19);          Mul(x, x19, x19);
+            uint[] x37 = Create();  Sqr(x19, 18, x37);      Mul(x18, x37, x37);
+            uint[] x74 = Create();  Sqr(x37, 37, x74);      Mul(x37, x74, x74);
+            uint[] x111 = Create(); Sqr(x74, 37, x111);     Mul(x37, x111, x111);
+            uint[] x222 = Create(); Sqr(x111, 111, x222);   Mul(x111, x222, x222);
+            uint[] x223 = Create(); Sqr(x222, x223);        Mul(x, x223, x223);
+
+            uint[] t = Create();
+            Sqr(x223, 223, t);
+            Mul(t, x222, z);
+        }
+
         private static void Reduce(uint[] z, int c)
         {
             uint z15 = z[15];
@@ -836,6 +893,38 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             }
         }
 
+        public static bool SqrtRatioVar(uint[] u, uint[] v, uint[] z)
+        {
+            uint[] u3v = Create();
+            uint[] u5v3 = Create();
+
+            Sqr(u, u3v);
+            Mul(u3v, v, u3v);
+            Sqr(u3v, u5v3);
+            Mul(u3v, u, u3v);
+            Mul(u5v3, u, u5v3);
+            Mul(u5v3, v, u5v3);
+
+            uint[] x = Create();
+            PowPm3d4(u5v3, x);
+            Mul(x, u3v, x);
+
+            uint[] t = Create();
+            Sqr(x, t);
+            Mul(t, v, t);
+
+            Sub(u, t, t);
+            Normalize(t);
+
+            if (IsZeroVar(t))
+            {
+                Copy(x, 0, z, 0);
+                return true;
+            }
+
+            return false;
+        }
+
         public static void Sub(uint[] x, uint[] y, uint[] z)
         {
             uint x0 = x[0], x1 = x[1], x2 = x[2], x3 = x[3], x4 = x[4], x5 = x[5], x6 = x[6], x7 = x[7];
@@ -900,5 +989,13 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
             z[14] = z14;
             z[15] = z15;
         }
+
+        public static void Zero(uint[] z)
+        {
+            for (int i = 0; i < Size; ++i)
+            {
+                z[i] = 0;
+            }
+        }
     }
 }
diff --git a/crypto/src/math/ec/rfc8032/Ed25519.cs b/crypto/src/math/ec/rfc8032/Ed25519.cs
new file mode 100644
index 000000000..ff4587cb2
--- /dev/null
+++ b/crypto/src/math/ec/rfc8032/Ed25519.cs
@@ -0,0 +1,937 @@
+using System;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+
+using Org.BouncyCastle.Crypto.Digests;
+using Org.BouncyCastle.Math.EC.Rfc7748;
+using Org.BouncyCastle.Math.Raw;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Math.EC.Rfc8032
+{
+    public abstract class Ed25519
+    {
+        private const long M28L = 0x0FFFFFFFL;
+        private const long M32L = 0xFFFFFFFFL;
+
+        private const int PointBytes = 32;
+        private const int ScalarUints = 8;
+        private const int ScalarBytes = ScalarUints * 4;
+
+        public static readonly int PublicKeySize = PointBytes;
+        public static readonly int SecretKeySize = 32;
+        public static readonly int SignatureSize = PointBytes + ScalarBytes;
+
+        //private static readonly byte[] Dom2Prefix = Strings.ToByteArray("SigEd25519 no Ed25519 collisions");
+
+        private static readonly uint[] P = { 0xFFFFFFEDU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0x7FFFFFFFU };
+        private static readonly uint[] L = { 0x5CF5D3EDU, 0x5812631AU, 0xA2F79CD6U, 0x14DEF9DEU, 0x00000000U, 0x00000000U, 0x00000000U, 0x10000000U };
+
+        private const int L0 = unchecked((int)0xFCF5D3ED);  // L0:26/--
+        private const int L1 =                0x012631A6;   // L1:24/22
+        private const int L2 =                0x079CD658;   // L2:27/--
+        private const int L3 = unchecked((int)0xFF9DEA2F);  // L3:23/--
+        private const int L4 =                0x000014DF;   // L4:12/11
+
+        private static readonly int[] B_x = { 0x0325D51A, 0x018B5823, 0x007B2C95, 0x0304A92D, 0x00D2598E, 0x01D6DC5C,
+            0x01388C7F, 0x013FEC0A, 0x029E6B72, 0x0042D26D };
+        private static readonly int[] B_y = { 0x02666658, 0x01999999, 0x00666666, 0x03333333, 0x00CCCCCC, 0x02666666,
+            0x01999999, 0x00666666, 0x03333333, 0x00CCCCCC, };
+        private static readonly int[] C_d = { 0x035978A3, 0x02D37284, 0x018AB75E, 0x026A0A0E, 0x0000E014, 0x0379E898,
+            0x01D01E5D, 0x01E738CC, 0x03715B7F, 0x00A406D9 };
+        private static readonly int[] C_d2 = { 0x02B2F159, 0x01A6E509, 0x01156EBD, 0x00D4141D, 0x0001C029, 0x02F3D130,
+            0x03A03CBB, 0x01CE7198, 0x02E2B6FF, 0x00480DB3 };
+        private static readonly int[] C_d4 = { 0x0165E2B2, 0x034DCA13, 0x002ADD7A, 0x01A8283B, 0x00038052, 0x01E7A260,
+            0x03407977, 0x019CE331, 0x01C56DFF, 0x00901B67 };
+
+        private const int WnafWidthBase = 7;
+
+        private const int PrecompBlocks = 8;
+        private const int PrecompTeeth = 4;
+        private const int PrecompSpacing = 8;
+        private const int PrecompPoints = 1 << (PrecompTeeth - 1);
+        private const int PrecompMask = PrecompPoints - 1;
+
+        // TODO[ed25519] Convert to PointPrecomp
+        private static PointExt[] precompBaseTable = null;
+        private static int[] precompBase = null;
+
+        private class PointAccum
+        {
+            internal int[] x = X25519Field.Create();
+            internal int[] y = X25519Field.Create();
+            internal int[] z = X25519Field.Create();
+            internal int[] u = X25519Field.Create();
+            internal int[] v = X25519Field.Create();
+        }
+
+        private class PointExt
+        {
+            internal int[] x = X25519Field.Create();
+            internal int[] y = X25519Field.Create();
+            internal int[] z = X25519Field.Create();
+            internal int[] t = X25519Field.Create();
+        }
+
+        private class PointPrecomp
+        {
+            internal int[] ypx_h = X25519Field.Create();
+            internal int[] ymx_h = X25519Field.Create();
+            internal int[] xyd = X25519Field.Create();
+        }
+
+        private static byte[] CalculateS(byte[] r, byte[] k, byte[] s)
+        {
+            uint[] t = new uint[ScalarUints * 2];   DecodeScalar(r, 0, t);
+            uint[] u = new uint[ScalarUints];       DecodeScalar(k, 0, u);
+            uint[] v = new uint[ScalarUints];       DecodeScalar(s, 0, v);
+
+            Nat256.MulAddTo(u, v, t);
+
+            byte[] result = new byte[ScalarBytes * 2];
+            for (int i = 0; i < t.Length; ++i)
+            {
+                Encode32(t[i], result, i * 4);
+            }
+            return ReduceScalar(result);
+        }
+
+        private static bool CheckPointVar(byte[] p)
+        {
+            uint[] t = new uint[8];
+            Decode32(p, 0, t, 0, 8);
+            t[7] &= 0x7FFFFFFFU;
+            return !Nat256.Gte(t, P);
+        }
+
+        private static bool CheckScalarVar(byte[] s)
+        {
+            uint[] n = new uint[ScalarUints];
+            DecodeScalar(s, 0, n);
+            return !Nat256.Gte(n, L);
+        }
+
+        private static uint Decode24(byte[] bs, int off)
+        {
+            uint n = bs[off];
+            n |= (uint)bs[++off] << 8;
+            n |= (uint)bs[++off] << 16;
+            return n;
+        }
+
+        private static uint Decode32(byte[] bs, int off)
+        {
+            uint n = bs[off];
+            n |= (uint)bs[++off] << 8;
+            n |= (uint)bs[++off] << 16;
+            n |= (uint)bs[++off] << 24;
+            return n;
+        }
+
+        private static void Decode32(byte[] bs, int bsOff, uint[] n, int nOff, int nLen)
+        {
+            for (int i = 0; i < nLen; ++i)
+            {
+                n[nOff + i] = Decode32(bs, bsOff + i * 4);
+            }
+        }
+
+        private static bool DecodePointVar(byte[] p, int pOff, bool negate, PointExt r)
+        {
+            byte[] py = Arrays.CopyOfRange(p, pOff, pOff + PointBytes);
+            if (!CheckPointVar(py))
+            {
+                return false;
+            }
+
+            int x_0 = (py[PointBytes - 1] & 0x80) >> 7;
+            py[PointBytes - 1] &= 0x7F;
+
+            X25519Field.Decode(py, 0, r.y);
+
+            int[] u = X25519Field.Create();
+            int[] v = X25519Field.Create();
+
+            X25519Field.Sqr(r.y, u);
+            X25519Field.Mul(C_d, u, v);
+            X25519Field.SubOne(u);
+            X25519Field.AddOne(v);
+
+            if (!X25519Field.SqrtRatioVar(u, v, r.x))
+            {
+                return false;
+            }
+
+            X25519Field.Normalize(r.x);
+            if (x_0 == 1 && X25519Field.IsZeroVar(r.x))
+            {
+                return false;
+            }
+
+            if (negate ^ (x_0 != (r.x[0] & 1)))
+            {
+                X25519Field.Negate(r.x, r.x);
+            }
+
+            PointExtendXY(r);
+            return true;
+        }
+
+        private static void DecodeScalar(byte[] k, int kOff, uint[] n)
+        {
+            Decode32(k, kOff, n, 0, ScalarUints);
+        }
+
+        private static void Encode24(uint n, byte[] bs, int off)
+        {
+            bs[off] = (byte)(n);
+            bs[++off] = (byte)(n >> 8);
+            bs[++off] = (byte)(n >> 16);
+        }
+
+        private static void Encode32(uint n, byte[] bs, int off)
+        {
+            bs[off] = (byte)(n);
+            bs[++off] = (byte)(n >> 8);
+            bs[++off] = (byte)(n >> 16);
+            bs[++off] = (byte)(n >> 24);
+        }
+
+        private static void Encode56(ulong n, byte[] bs, int off)
+        {
+            Encode32((uint)n, bs, off);
+            Encode24((uint)(n >> 32), bs, off + 4);
+        }
+
+        private static void EncodePoint(PointAccum p, byte[] r, int rOff)
+        {
+            int[] x = X25519Field.Create();
+            int[] y = X25519Field.Create();
+
+            X25519Field.Inv(p.z, y);
+            X25519Field.Mul(p.x, y, x);
+            X25519Field.Mul(p.y, y, y);
+            X25519Field.Normalize(x);
+            X25519Field.Normalize(y);
+
+            X25519Field.Encode(y, r, rOff);
+            r[rOff + PointBytes - 1] |= (byte)((x[0] & 1) << 7);
+        }
+
+        public static void GeneratePublicKey(byte[] sk, int skOff, byte[] pk, int pkOff)
+        {
+            Sha512Digest d = new Sha512Digest();
+            byte[] h = new byte[d.GetDigestSize()];
+
+            d.BlockUpdate(sk, skOff, SecretKeySize);
+            d.DoFinal(h, 0);
+
+            byte[] s = new byte[ScalarBytes];
+            PruneScalar(h, 0, s);
+
+            ScalarMultBaseEncoded(s, pk, pkOff);
+        }
+
+        private static sbyte[] GetWnaf(uint[] n, int width)
+        {
+            Debug.Assert(n[ScalarUints - 1] >> 31 == 0);
+
+            uint[] t = new uint[ScalarUints * 2];
+            {
+                uint c = 0;
+                int tPos = t.Length, i = ScalarUints;
+                while (--i >= 0)
+                {
+                    uint next = n[i];
+                    t[--tPos] = (next >> 16) | (c << 16);
+                    t[--tPos] = c = next;
+                }
+            }
+
+            sbyte[] ws = new sbyte[256];
+
+            uint pow2 = 1U << width;
+            uint mask = pow2 - 1U;
+            uint sign = pow2 >> 1;
+
+            uint carry = 0U;
+            int j = 0;
+            for (int i = 0; i < t.Length; ++i, j -= 16)
+            {
+                uint word = t[i];
+                while (j < 16)
+                {
+                    uint word16 = word >> j;
+                    uint bit = word16 & 1U;
+
+                    if (bit == carry)
+                    {
+                        ++j;
+                        continue;
+                    }
+
+                    uint digit = (word16 & mask) + carry;
+                    carry = digit & sign;
+                    digit -= (carry << 1);
+                    carry >>= (width - 1);
+
+                    ws[(i << 4) + j] = (sbyte)digit;
+
+                    j += width;
+                }
+            }
+
+            Debug.Assert(carry == 0);
+
+            return ws;
+        }
+
+        private static void ImplSign(Sha512Digest d, byte[] h, byte[] s, byte[] pk, int pkOff, byte[] m, int mOff, int mLen, byte[] sig, int sigOff)
+        {
+            d.BlockUpdate(h, ScalarBytes, ScalarBytes);
+            d.BlockUpdate(m, mOff, mLen);
+            d.DoFinal(h, 0);
+
+            byte[] r = ReduceScalar(h);
+            byte[] R = new byte[PointBytes];
+            ScalarMultBaseEncoded(r, R, 0);
+
+            d.BlockUpdate(R, 0, PointBytes);
+            d.BlockUpdate(pk, 0, PointBytes);
+            d.BlockUpdate(m, mOff, mLen);
+            d.DoFinal(h, 0);
+
+            byte[] k = ReduceScalar(h);
+            byte[] S = CalculateS(r, k, s);
+
+            Array.Copy(R, 0, sig, sigOff, PointBytes);
+            Array.Copy(S, 0, sig, sigOff + PointBytes, ScalarBytes);
+        }
+
+        private static void PointAddVar(bool negate, PointExt p, PointAccum r)
+        {
+            int[] A = X25519Field.Create();
+            int[] B = X25519Field.Create();
+            int[] C = X25519Field.Create();
+            int[] D = X25519Field.Create();
+            int[] E = r.u;
+            int[] F = X25519Field.Create();
+            int[] G = X25519Field.Create();
+            int[] H = r.v;
+
+            int[] c, d, f, g;
+            if (negate)
+            {
+                c = D; d = C; f = G; g = F;
+            }
+            else
+            {
+                c = C; d = D; f = F; g = G;
+            }
+
+            X25519Field.Apm(r.y, r.x, B, A);
+            X25519Field.Apm(p.y, p.x, d, c);
+            X25519Field.Mul(A, C, A);
+            X25519Field.Mul(B, D, B);
+            X25519Field.Mul(r.u, r.v, C);
+            X25519Field.Mul(C, p.t, C);
+            X25519Field.Mul(C, C_d2, C);
+            X25519Field.Mul(r.z, p.z, D);
+            X25519Field.Add(D, D, D);
+            X25519Field.Apm(B, A, H, E);
+            X25519Field.Apm(D, C, g, f);
+            X25519Field.Carry(g);
+            X25519Field.Mul(E, F, r.x);
+            X25519Field.Mul(G, H, r.y);
+            X25519Field.Mul(F, G, r.z);
+        }
+
+        private static void PointAddVar(bool negate, PointExt p, PointExt q, PointExt r)
+        {
+            int[] A = X25519Field.Create();
+            int[] B = X25519Field.Create();
+            int[] C = X25519Field.Create();
+            int[] D = X25519Field.Create();
+            int[] E = X25519Field.Create();
+            int[] F = X25519Field.Create();
+            int[] G = X25519Field.Create();
+            int[] H = X25519Field.Create();
+
+            int[] c, d, f, g;
+            if (negate)
+            {
+                c = D; d = C; f = G; g = F;
+            }
+            else
+            {
+                c = C; d = D; f = F; g = G;
+            }
+
+            X25519Field.Apm(p.y, p.x, B, A);
+            X25519Field.Apm(q.y, q.x, d, c);
+            X25519Field.Mul(A, C, A);
+            X25519Field.Mul(B, D, B);
+            X25519Field.Mul(p.t, q.t, C);
+            X25519Field.Mul(C, C_d2, C);
+            X25519Field.Mul(p.z, q.z, D);
+            X25519Field.Add(D, D, D);
+            X25519Field.Apm(B, A, H, E);
+            X25519Field.Apm(D, C, g, f);
+            X25519Field.Carry(g);
+            X25519Field.Mul(E, F, r.x);
+            X25519Field.Mul(G, H, r.y);
+            X25519Field.Mul(F, G, r.z);
+            X25519Field.Mul(E, H, r.t);
+        }
+
+        private static void PointAddPrecomp(PointPrecomp p, PointAccum r)
+        {
+            int[] A = X25519Field.Create();
+            int[] B = X25519Field.Create();
+            int[] C = X25519Field.Create();
+            int[] E = r.u;
+            int[] F = X25519Field.Create();
+            int[] G = X25519Field.Create();
+            int[] H = r.v;
+
+            X25519Field.Apm(r.y, r.x, B, A);
+            X25519Field.Mul(A, p.ymx_h, A);
+            X25519Field.Mul(B, p.ypx_h, B);
+            X25519Field.Mul(r.u, r.v, C);
+            X25519Field.Mul(C, p.xyd, C);
+            X25519Field.Apm(B, A, H, E);
+            X25519Field.Apm(r.z, C, G, F);
+            X25519Field.Carry(G);
+            X25519Field.Mul(E, F, r.x);
+            X25519Field.Mul(G, H, r.y);
+            X25519Field.Mul(F, G, r.z);
+        }
+
+        private static PointExt PointCopy(PointAccum p)
+        {
+            PointExt r = new PointExt();
+            X25519Field.Copy(p.x, 0, r.x, 0);
+            X25519Field.Copy(p.y, 0, r.y, 0);
+            X25519Field.Copy(p.z, 0, r.z, 0);
+            X25519Field.Mul(p.u, p.v, r.t);
+            return r;
+        }
+
+        private static PointExt PointCopy(PointExt p)
+        {
+            PointExt r = new PointExt();
+            X25519Field.Copy(p.x, 0, r.x, 0);
+            X25519Field.Copy(p.y, 0, r.y, 0);
+            X25519Field.Copy(p.z, 0, r.z, 0);
+            X25519Field.Copy(p.t, 0, r.t, 0);
+            return r;
+        }
+
+        private static void PointDouble(PointAccum r)
+        {
+            int[] A = X25519Field.Create();
+            int[] B = X25519Field.Create();
+            int[] C = X25519Field.Create();
+            int[] E = r.u;
+            int[] F = X25519Field.Create();
+            int[] G = X25519Field.Create();
+            int[] H = r.v;
+
+            X25519Field.Sqr(r.x, A);
+            X25519Field.Sqr(r.y, B);
+            X25519Field.Sqr(r.z, C);
+            X25519Field.Add(C, C, C);
+            X25519Field.Apm(A, B, H, G);
+            X25519Field.Add(r.x, r.y, E);
+            X25519Field.Sqr(E, E);
+            X25519Field.Sub(H, E, E);
+            X25519Field.Add(C, G, F);
+            X25519Field.Carry(F);
+            X25519Field.Mul(E, F, r.x);
+            X25519Field.Mul(G, H, r.y);
+            X25519Field.Mul(F, G, r.z);
+        }
+
+        private static void PointExtendXY(PointAccum p)
+        {
+            X25519Field.One(p.z);
+            X25519Field.Copy(p.x, 0, p.u, 0);
+            X25519Field.Copy(p.y, 0, p.v, 0);
+        }
+
+        private static void PointExtendXY(PointExt p)
+        {
+            X25519Field.One(p.z);
+            X25519Field.Mul(p.x, p.y, p.t);
+        }
+
+        private static void PointLookup(int block, int index, PointPrecomp p)
+        {
+            Debug.Assert(0 <= block && block < PrecompBlocks);
+            Debug.Assert(0 <= index && index < PrecompPoints);
+
+            int off = block * PrecompPoints * 3 * X25519Field.Size;
+
+            for (int i = 0; i < PrecompPoints; ++i)
+            {
+                int mask = ((i ^ index) - 1) >> 31;
+                Nat.CMov(X25519Field.Size, mask, precompBase, off, p.ypx_h, 0); off += X25519Field.Size;
+                Nat.CMov(X25519Field.Size, mask, precompBase, off, p.ymx_h, 0); off += X25519Field.Size;
+                Nat.CMov(X25519Field.Size, mask, precompBase, off, p.xyd, 0);   off += X25519Field.Size;
+            }
+        }
+
+        private static PointExt[] PointPrecompVar(PointExt p, int count)
+        {
+            Debug.Assert(count > 0);
+
+            PointExt d = new PointExt();
+            PointAddVar(false, p, p, d);
+
+            PointExt[] table = new PointExt[count];
+            table[0] = PointCopy(p);
+            for (int i = 1; i < count; ++i)
+            {
+                PointAddVar(false, table[i - 1], d, table[i] = new PointExt());
+            }
+            return table;
+        }
+
+        private static void PointSetNeutral(PointAccum p)
+        {
+            X25519Field.Zero(p.x);
+            X25519Field.One(p.y);
+            X25519Field.One(p.z);
+            X25519Field.Zero(p.u);
+            X25519Field.One(p.v);
+        }
+
+        private static void PointSetNeutral(PointExt p)
+        {
+            X25519Field.Zero(p.x);
+            X25519Field.One(p.y);
+            X25519Field.One(p.z);
+            X25519Field.Zero(p.t);
+        }
+
+        [MethodImpl(MethodImplOptions.Synchronized)]
+        public static void Precompute()
+        {
+            if (precompBase != null)
+            {
+                return;
+            }
+
+            // Precomputed table for the base point in verification ladder
+            {
+                PointExt b = new PointExt();
+                X25519Field.Copy(B_x, 0, b.x, 0);
+                X25519Field.Copy(B_y, 0, b.y, 0);
+                PointExtendXY(b);
+
+                precompBaseTable = PointPrecompVar(b, 1 << (WnafWidthBase - 2));
+            }
+
+            PointAccum p = new PointAccum();
+            X25519Field.Copy(B_x, 0, p.x, 0);
+            X25519Field.Copy(B_y, 0, p.y, 0);
+            PointExtendXY(p);
+
+            precompBase = new int[PrecompBlocks * PrecompPoints * 3 * X25519Field.Size];
+
+            int off = 0;
+            for (int b = 0; b < PrecompBlocks; ++b)
+            {
+                PointExt[] ds = new PointExt[PrecompTeeth];
+
+                PointExt sum = new PointExt();
+                PointSetNeutral(sum);
+
+                for (int t = 0; t < PrecompTeeth; ++t)
+                {
+                    PointExt q = PointCopy(p);
+                    PointAddVar(true, sum, q, sum);
+                    PointDouble(p);
+
+                    ds[t] = PointCopy(p);
+
+                    for (int s = 1; s < PrecompSpacing; ++s)
+                    {
+                        PointDouble(p);
+                    }
+                }
+
+                PointExt[] points = new PointExt[PrecompPoints];
+                int k = 0;
+                points[k++] = sum;
+
+                for (int t = 0; t < (PrecompTeeth - 1); ++t)
+                {
+                    int size = 1 << t;
+                    for (int j = 0; j < size; ++j, ++k)
+                    {
+                        PointAddVar(false, points[k - size], ds[t], points[k] = new PointExt());
+                    }
+                }
+
+                Debug.Assert(k == PrecompPoints);
+
+                for (int i = 0; i < PrecompPoints; ++i)
+                {
+                    PointExt q = points[i];
+
+                    int[] x = X25519Field.Create();
+                    int[] y = X25519Field.Create();
+
+                    X25519Field.Add(q.z, q.z, x);
+                    // TODO[ed25519] Batch inversion
+                    X25519Field.Inv(x, y);
+                    X25519Field.Mul(q.x, y, x);
+                    X25519Field.Mul(q.y, y, y);
+
+                    PointPrecomp r = new PointPrecomp();
+                    X25519Field.Apm(y, x, r.ypx_h, r.ymx_h);
+                    X25519Field.Mul(x, y, r.xyd);
+                    X25519Field.Mul(r.xyd, C_d4, r.xyd);
+
+                    X25519Field.Normalize(r.ypx_h);
+                    X25519Field.Normalize(r.ymx_h);
+                    //X25519Field.Normalize(r.xyd);
+
+                    X25519Field.Copy(r.ypx_h, 0, precompBase, off); off += X25519Field.Size;
+                    X25519Field.Copy(r.ymx_h, 0, precompBase, off); off += X25519Field.Size;
+                    X25519Field.Copy(r.xyd, 0, precompBase, off);   off += X25519Field.Size;
+                }
+            }
+
+            Debug.Assert(off == precompBase.Length);
+        }
+
+        private static void PruneScalar(byte[] n, int nOff, byte[] r)
+        {
+            Array.Copy(n, nOff, r, 0, ScalarBytes);
+
+            r[0] &= 0xF8;
+            r[ScalarBytes - 1] &= 0x7F;
+            r[ScalarBytes - 1] |= 0x40;
+        }
+
+        private static byte[] ReduceScalar(byte[] n)
+        {
+            long x00 = Decode32(n,  0) & M32L;          // x00:32/--
+            long x01 = (Decode24(n, 4) << 4) & M32L;    // x01:28/--
+            long x02 = Decode32(n,  7) & M32L;          // x02:32/--
+            long x03 = (Decode24(n, 11) << 4) & M32L;   // x03:28/--
+            long x04 = Decode32(n, 14) & M32L;          // x04:32/--
+            long x05 = (Decode24(n, 18) << 4) & M32L;   // x05:28/--
+            long x06 = Decode32(n, 21) & M32L;          // x06:32/--
+            long x07 = (Decode24(n, 25) << 4) & M32L;   // x07:28/--
+            long x08 = Decode32(n, 28) & M32L;          // x08:32/--
+            long x09 = (Decode24(n, 32) << 4) & M32L;   // x09:28/--
+            long x10 = Decode32(n, 35) & M32L;          // x10:32/--
+            long x11 = (Decode24(n, 39) << 4) & M32L;   // x11:28/--
+            long x12 = Decode32(n, 42) & M32L;          // x12:32/--
+            long x13 = (Decode24(n, 46) << 4) & M32L;   // x13:28/--
+            long x14 = Decode32(n, 49) & M32L;          // x14:32/--
+            long x15 = (Decode24(n, 53) << 4) & M32L;   // x15:28/--
+            long x16 = Decode32(n, 56) & M32L;          // x16:32/--
+            long x17 = (Decode24(n, 60) << 4) & M32L;   // x17:28/--
+            long x18 = n[63] & 0xFFL;                   // x18:08/--
+            long t;
+
+            //x18 += (x17 >> 28); x17 &= M28L;
+            x09 -= x18 * L0;                            // x09:34/28
+            x10 -= x18 * L1;                            // x10:33/30
+            x11 -= x18 * L2;                            // x11:35/28
+            x12 -= x18 * L3;                            // x12:32/31
+            x13 -= x18 * L4;                            // x13:28/21
+
+            x17 += (x16 >> 28); x16 &= M28L;            // x17:28/--, x16:28/--
+            x08 -= x17 * L0;                            // x08:54/32
+            x09 -= x17 * L1;                            // x09:52/51
+            x10 -= x17 * L2;                            // x10:55/34
+            x11 -= x17 * L3;                            // x11:51/36
+            x12 -= x17 * L4;                            // x12:41/--
+
+            //x16 += (x15 >> 28); x15 &= M28L;
+            x07 -= x16 * L0;                            // x07:54/28
+            x08 -= x16 * L1;                            // x08:54/53
+            x09 -= x16 * L2;                            // x09:55/53
+            x10 -= x16 * L3;                            // x10:55/52
+            x11 -= x16 * L4;                            // x11:51/41
+
+            x15 += (x14 >> 28); x14 &= M28L;            // x15:28/--, x14:28/--
+            x06 -= x15 * L0;                            // x06:54/32
+            x07 -= x15 * L1;                            // x07:54/53
+            x08 -= x15 * L2;                            // x08:56/--
+            x09 -= x15 * L3;                            // x09:55/54
+            x10 -= x15 * L4;                            // x10:55/53
+
+            //x14 += (x13 >> 28); x13 &= M28L;
+            x05 -= x14 * L0;                            // x05:54/28
+            x06 -= x14 * L1;                            // x06:54/53
+            x07 -= x14 * L2;                            // x07:56/--
+            x08 -= x14 * L3;                            // x08:56/51
+            x09 -= x14 * L4;                            // x09:56/--
+
+            x13 += (x12 >> 28); x12 &= M28L;            // x13:28/22, x12:28/--
+            x04 -= x13 * L0;                            // x04:54/49
+            x05 -= x13 * L1;                            // x05:54/53
+            x06 -= x13 * L2;                            // x06:56/--
+            x07 -= x13 * L3;                            // x07:56/52
+            x08 -= x13 * L4;                            // x08:56/52
+
+            x12 += (x11 >> 28); x11 &= M28L;            // x12:28/24, x11:28/--
+            x03 -= x12 * L0;                            // x03:54/49
+            x04 -= x12 * L1;                            // x04:54/51
+            x05 -= x12 * L2;                            // x05:56/--
+            x06 -= x12 * L3;                            // x06:56/52
+            x07 -= x12 * L4;                            // x07:56/53
+
+            x11 += (x10 >> 28); x10 &= M28L;            // x11:29/--, x10:28/--
+            x02 -= x11 * L0;                            // x02:55/32
+            x03 -= x11 * L1;                            // x03:55/--
+            x04 -= x11 * L2;                            // x04:56/55
+            x05 -= x11 * L3;                            // x05:56/52
+            x06 -= x11 * L4;                            // x06:56/53
+
+            x10 += (x09 >> 28); x09 &= M28L;            // x10:29/--, x09:28/--
+            x01 -= x10 * L0;                            // x01:55/28
+            x02 -= x10 * L1;                            // x02:55/54
+            x03 -= x10 * L2;                            // x03:56/55
+            x04 -= x10 * L3;                            // x04:57/--
+            x05 -= x10 * L4;                            // x05:56/53
+
+            x08 += (x07 >> 28); x07 &= M28L;            // x08:56/53, x07:28/--
+            x09 += (x08 >> 28); x08 &= M28L;            // x09:29/25, x08:28/--
+
+            t    = (x08 >> 27) & 1L;
+            x09 += t;                                   // x09:29/26
+
+            x00 -= x09 * L0;                            // x00:55/53
+            x01 -= x09 * L1;                            // x01:55/54
+            x02 -= x09 * L2;                            // x02:57/--
+            x03 -= x09 * L3;                            // x03:57/--
+            x04 -= x09 * L4;                            // x04:57/42
+
+            x01 += (x00 >> 28); x00 &= M28L;
+            x02 += (x01 >> 28); x01 &= M28L;
+            x03 += (x02 >> 28); x02 &= M28L;
+            x04 += (x03 >> 28); x03 &= M28L;
+            x05 += (x04 >> 28); x04 &= M28L;
+            x06 += (x05 >> 28); x05 &= M28L;
+            x07 += (x06 >> 28); x06 &= M28L;
+            x08 += (x07 >> 28); x07 &= M28L;
+            x09  = (x08 >> 28); x08 &= M28L;
+
+            x09 -= t;
+
+            Debug.Assert(x09 == 0L || x09 == -1L);
+
+            x00 += x09 & L0;
+            x01 += x09 & L1;
+            x02 += x09 & L2;
+            x03 += x09 & L3;
+            x04 += x09 & L4;
+
+            x01 += (x00 >> 28); x00 &= M28L;
+            x02 += (x01 >> 28); x01 &= M28L;
+            x03 += (x02 >> 28); x02 &= M28L;
+            x04 += (x03 >> 28); x03 &= M28L;
+            x05 += (x04 >> 28); x04 &= M28L;
+            x06 += (x05 >> 28); x05 &= M28L;
+            x07 += (x06 >> 28); x06 &= M28L;
+            x08 += (x07 >> 28); x07 &= M28L;
+
+            byte[] r = new byte[ScalarBytes];
+            Encode56((ulong)(x00 | (x01 << 28)), r, 0);
+            Encode56((ulong)(x02 | (x03 << 28)), r, 7);
+            Encode56((ulong)(x04 | (x05 << 28)), r, 14);
+            Encode56((ulong)(x06 | (x07 << 28)), r, 21);
+            Encode32((uint)x08, r, 28);
+            return r;
+        }
+
+        private static void ScalarMultBase(byte[] k, PointAccum r)
+        {
+            Precompute();
+
+            PointSetNeutral(r);
+
+            uint[] n = new uint[ScalarUints];
+            DecodeScalar(k, 0, n);
+
+            // Recode the scalar into signed-digit form, then group comb bits in each block
+            {
+                uint c1 = Nat.CAdd(ScalarUints, ~(int)n[0] & 1, n, L, n);   Debug.Assert(c1 == 0);
+                uint c2 = Nat.ShiftDownBit(ScalarUints, n, 1U);             Debug.Assert(c2 == (1U << 31));
+
+                for (int i = 0; i < ScalarUints; ++i)
+                {
+                    n[i] = Interleave.Shuffle2(n[i]);
+                }
+            }
+
+            PointPrecomp p = new PointPrecomp();
+
+            int cOff = (PrecompSpacing - 1) * PrecompTeeth;
+            for (; ; )
+            {
+                for (int b = 0; b < PrecompBlocks; ++b)
+                {
+                    uint w = n[b] >> cOff;
+                    int sign = (int)(w >> (PrecompTeeth - 1)) & 1;
+                    int abs = ((int)w ^ -sign) & PrecompMask;
+
+                    Debug.Assert(sign == 0 || sign == 1);
+                    Debug.Assert(0 <= abs && abs < PrecompPoints);
+
+                    PointLookup(b, abs, p);
+
+                    X25519Field.CSwap(sign, p.ypx_h, p.ymx_h);
+                    X25519Field.CNegate(sign, p.xyd);
+
+                    PointAddPrecomp(p, r);
+                }
+
+                if ((cOff -= PrecompTeeth) < 0)
+                {
+                    break;
+                }
+
+                PointDouble(r);
+            }
+        }
+
+        private static void ScalarMultBaseEncoded(byte[] k, byte[] r, int rOff)
+        {
+            PointAccum p = new PointAccum();
+            ScalarMultBase(k, p);
+            EncodePoint(p, r, rOff);
+        }
+
+        private static void ScalarMultStraussVar(uint[] nb, uint[] np, PointExt p, PointAccum r)
+        {
+            Precompute();
+
+            int width = 5;
+
+            sbyte[] ws_b = GetWnaf(nb, WnafWidthBase);
+            sbyte[] ws_p = GetWnaf(np, width);
+
+            PointExt[] tp = PointPrecompVar(p, 1 << (width - 2));
+
+            PointSetNeutral(r);
+
+            int bit = 255;
+            while (bit > 0 && (ws_b[bit] | ws_p[bit]) == 0)
+            {
+                --bit;
+            }
+
+            for (; ; )
+            {
+                int wb = ws_b[bit];
+                if (wb != 0)
+                {
+                    int sign = wb >> 31;
+                    int index = (wb ^ sign) >> 1;
+
+                    PointAddVar((sign != 0), precompBaseTable[index], r);
+                }
+
+                int wp = ws_p[bit];
+                if (wp != 0)
+                {
+                    int sign = wp >> 31;
+                    int index = (wp ^ sign) >> 1;
+
+                    PointAddVar((sign != 0), tp[index], r);
+                }
+
+                if (--bit < 0)
+                {
+                    break;
+                }
+
+                PointDouble(r);
+            }
+        }
+
+        public static void Sign(byte[] sk, int skOff, byte[] m, int mOff, int mLen, byte[] sig, int sigOff)
+        {
+            Sha512Digest d = new Sha512Digest();
+            byte[] h = new byte[d.GetDigestSize()];
+
+            d.BlockUpdate(sk, skOff, SecretKeySize);
+            d.DoFinal(h, 0);
+
+            byte[] s = new byte[ScalarBytes];
+            PruneScalar(h, 0, s);
+
+            byte[] pk = new byte[PointBytes];
+            ScalarMultBaseEncoded(s, pk, 0);
+
+            ImplSign(d, h, s, pk, 0, m, mOff, mLen, sig, sigOff);
+        }
+
+        public static void Sign(byte[] sk, int skOff, byte[] pk, int pkOff, byte[] m, int mOff, int mLen, byte[] sig, int sigOff)
+        {
+            Sha512Digest d = new Sha512Digest();
+            byte[] h = new byte[d.GetDigestSize()];
+
+            d.BlockUpdate(sk, skOff, SecretKeySize);
+            d.DoFinal(h, 0);
+
+            byte[] s = new byte[ScalarBytes];
+            PruneScalar(h, 0, s);
+
+            ImplSign(d, h, s, pk, pkOff, m, mOff, mLen, sig, sigOff);
+        }
+
+        public static bool Verify(byte[] sig, int sigOff, byte[] pk, int pkOff, byte[] m, int mOff, int mLen)
+        {
+            byte[] R = Arrays.CopyOfRange(sig, sigOff, sigOff + PointBytes);
+            byte[] S = Arrays.CopyOfRange(sig, sigOff + PointBytes, sigOff + SignatureSize);
+
+            if (!CheckPointVar(R))
+            {
+                return false;
+            }
+            if (!CheckScalarVar(S))
+            {
+                return false;
+            }
+
+            PointExt pA = new PointExt();
+            if (!DecodePointVar(pk, pkOff, true, pA))
+            {
+                return false;
+            }
+
+            Sha512Digest d = new Sha512Digest();
+            byte[] h = new byte[d.GetDigestSize()];
+
+            d.BlockUpdate(R, 0, PointBytes);
+            d.BlockUpdate(pk, pkOff, PointBytes);
+            d.BlockUpdate(m, mOff, mLen);
+            d.DoFinal(h, 0);
+
+            byte[] k = ReduceScalar(h);
+
+            uint[] nS = new uint[ScalarUints];
+            DecodeScalar(S, 0, nS);
+
+            uint[] nA = new uint[ScalarUints];
+            DecodeScalar(k, 0, nA);
+
+            PointAccum pR = new PointAccum();
+            ScalarMultStraussVar(nS, nA, pA, pR);
+
+            byte[] check = new byte[PointBytes];
+            EncodePoint(pR, check, 0);
+
+            return Arrays.AreEqual(check, R);
+        }
+    }
+}
diff --git a/crypto/src/math/ec/rfc8032/Ed448.cs b/crypto/src/math/ec/rfc8032/Ed448.cs
new file mode 100644
index 000000000..52c215160
--- /dev/null
+++ b/crypto/src/math/ec/rfc8032/Ed448.cs
@@ -0,0 +1,1067 @@
+using System;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+
+using Org.BouncyCastle.Crypto.Digests;
+using Org.BouncyCastle.Math.EC.Rfc7748;
+using Org.BouncyCastle.Math.Raw;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Math.EC.Rfc8032
+{
+    public abstract class Ed448
+    {
+        private const ulong M26UL = 0x03FFFFFFUL;
+        private const ulong M28UL = 0x0FFFFFFFUL;
+
+        private const int PointBytes = 57;
+        private const int ScalarUints = 14;
+        private const int ScalarBytes = ScalarUints * 4 + 1;
+
+        public static readonly int PublicKeySize = PointBytes;
+        public static readonly int SecretKeySize = 57;
+        public static readonly int SignatureSize = PointBytes + ScalarBytes;
+
+        private static readonly byte[] Dom4Prefix = Strings.ToByteArray("SigEd448");
+
+        private static readonly uint[] P = { 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU,
+            0xFFFFFFFEU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU };
+        private static readonly uint[] L = { 0xAB5844F3U, 0x2378C292U, 0x8DC58F55U, 0x216CC272U, 0xAED63690U, 0xC44EDB49U, 0x7CCA23E9U,
+            0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0x3FFFFFFFU };
+        private static readonly BigInteger N = Nat.ToBigInteger(L.Length, L);
+
+        private const int L_0 = 0x04A7BB0D;     // L_0:26/24
+        private const int L_1 = 0x0873D6D5;     // L_1:27/23
+        private const int L_2 = 0x0A70AADC;     // L_2:27/26
+        private const int L_3 = 0x03D8D723;     // L_3:26/--
+        private const int L_4 = 0x096FDE93;     // L_4:27/25
+        private const int L_5 = 0x0B65129C;     // L_5:27/26
+        private const int L_6 = 0x063BB124;     // L_6:27/--
+        private const int L_7 = 0x08335DC1;     // L_7:27/22
+
+        private const int L4_0 = 0x029EEC34;    // L4_0:25/24
+        private const int L4_1 = 0x01CF5B55;    // L4_1:25/--
+        private const int L4_2 = 0x09C2AB72;    // L4_2:27/25
+        private const int L4_3 = 0x0F635C8E;    // L4_3:28/--
+        private const int L4_4 = 0x05BF7A4C;    // L4_4:26/25
+        private const int L4_5 = 0x0D944A72;    // L4_5:28/--
+        private const int L4_6 = 0x08EEC492;    // L4_6:27/24
+        private const int L4_7 = 0x20CD7705;    // L4_7:29/24
+
+        private static readonly uint[] B_x = { 0x070CC05EU, 0x026A82BCU, 0x00938E26U, 0x080E18B0U, 0x0511433BU, 0x0F72AB66U, 0x0412AE1AU,
+            0x0A3D3A46U, 0x0A6DE324U, 0x00F1767EU, 0x04657047U, 0x036DA9E1U, 0x05A622BFU, 0x0ED221D1U, 0x066BED0DU, 0x04F1970CU };
+        private static readonly uint[] B_y = { 0x0230FA14U, 0x008795BFU, 0x07C8AD98U, 0x0132C4EDU, 0x09C4FDBDU, 0x01CE67C3U, 0x073AD3FFU,
+            0x005A0C2DU, 0x07789C1EU, 0x0A398408U, 0x0A73736CU, 0x0C7624BEU, 0x003756C9U, 0x02488762U, 0x016EB6BCU, 0x0693F467U };
+        private const int C_d = -39081;
+
+        private const int WnafWidthBase = 7;
+
+        private const int PrecompBlocks = 5;
+        private const int PrecompTeeth = 5;
+        private const int PrecompSpacing = 18;
+        private const int PrecompPoints = 1 << (PrecompTeeth - 1);
+        private const int PrecompMask = PrecompPoints - 1;
+
+        // TODO[ed448] Convert to PointPrecomp
+        private static PointExt[] precompBaseTable = null;
+        private static uint[] precompBase = null;
+
+        private class PointExt
+        {
+            internal uint[] x = X448Field.Create();
+            internal uint[] y = X448Field.Create();
+            internal uint[] z = X448Field.Create();
+        }
+
+        private class PointPrecomp
+        {
+            internal uint[] x = X448Field.Create();
+            internal uint[] y = X448Field.Create();
+        }
+
+        private static byte[] CalculateS(byte[] r, byte[] k, byte[] s)
+        {
+            uint[] t = new uint[ScalarUints * 2];   DecodeScalar(r, 0, t);
+            uint[] u = new uint[ScalarUints];       DecodeScalar(k, 0, u);
+            uint[] v = new uint[ScalarUints];       DecodeScalar(s, 0, v);
+
+            Nat.MulAddTo(14, u, v, t);
+
+            byte[] result = new byte[ScalarBytes * 2];
+            for (int i = 0; i < t.Length; ++i)
+            {
+                Encode32(t[i], result, i * 4);
+            }
+            return ReduceScalar(result);
+        }
+
+        private static bool CheckContextVar(byte[] ctx)
+        {
+            return ctx != null && ctx.Length < 256;
+        }
+
+        private static bool CheckPointVar(byte[] p)
+        {
+            if ((p[PointBytes - 1] & 0x7F) != 0x00)
+            {
+                return false;
+            }
+
+            uint[] t = new uint[14];
+            Decode32(p, 0, t, 0, 14);
+            return !Nat.Gte(14, t, P);
+        }
+
+        private static bool CheckScalarVar(byte[] s)
+        {
+            if (s[ScalarBytes - 1] != 0x00)
+            {
+                return false;
+            }
+
+            uint[] n = new uint[ScalarUints];
+            DecodeScalar(s, 0, n);
+            return !Nat.Gte(ScalarUints, n, L);
+        }
+
+        private static uint Decode16(byte[] bs, int off)
+        {
+            uint n = bs[off];
+            n |= (uint)bs[++off] << 8;
+            return n;
+        }
+
+        private static uint Decode24(byte[] bs, int off)
+        {
+            uint n = bs[off];
+            n |= (uint)bs[++off] << 8;
+            n |= (uint)bs[++off] << 16;
+            return n;
+        }
+
+        private static uint Decode32(byte[] bs, int off)
+        {
+            uint n = bs[off];
+            n |= (uint)bs[++off] << 8;
+            n |= (uint)bs[++off] << 16;
+            n |= (uint)bs[++off] << 24;
+            return n;
+        }
+
+        private static void Decode32(byte[] bs, int bsOff, uint[] n, int nOff, int nLen)
+        {
+            for (int i = 0; i < nLen; ++i)
+            {
+                n[nOff + i] = Decode32(bs, bsOff + i * 4);
+            }
+        }
+
+        private static bool DecodePointVar(byte[] p, int pOff, bool negate, PointExt r)
+        {
+            byte[] py = Arrays.CopyOfRange(p, pOff, pOff + PointBytes);
+            if (!CheckPointVar(py))
+            {
+                return false;
+            }
+
+            int x_0 = (py[PointBytes - 1] & 0x80) >> 7;
+            py[PointBytes - 1] &= 0x7F;
+
+            X448Field.Decode(py, 0, r.y);
+
+            uint[] u = X448Field.Create();
+            uint[] v = X448Field.Create();
+
+            X448Field.Sqr(r.y, u);
+            X448Field.Mul(u, (uint)-C_d, v);
+            X448Field.Negate(u, u);
+            X448Field.AddOne(u);
+            X448Field.AddOne(v);
+
+            if (!X448Field.SqrtRatioVar(u, v, r.x))
+            {
+                return false;
+            }
+
+            X448Field.Normalize(r.x);
+            if (x_0 == 1 && X448Field.IsZeroVar(r.x))
+            {
+                return false;
+            }
+
+            if (negate ^ (x_0 != (r.x[0] & 1)))
+            {
+                X448Field.Negate(r.x, r.x);
+            }
+
+            PointExtendXY(r);
+            return true;
+        }
+
+        private static void DecodeScalar(byte[] k, int kOff, uint[] n)
+        {
+            Debug.Assert(k[kOff + ScalarBytes - 1] == 0x00);
+
+            Decode32(k, kOff, n, 0, ScalarUints);
+        }
+
+        private static void Dom4(ShakeDigest d, byte x, byte[] y)
+        {
+            d.BlockUpdate(Dom4Prefix, 0, Dom4Prefix.Length);
+            d.Update(x);
+            d.Update((byte)y.Length);
+            d.BlockUpdate(y, 0, y.Length);
+        }
+
+        private static void Encode24(uint n, byte[] bs, int off)
+        {
+            bs[off] = (byte)(n);
+            bs[++off] = (byte)(n >> 8);
+            bs[++off] = (byte)(n >> 16);
+        }
+
+        private static void Encode32(uint n, byte[] bs, int off)
+        {
+            bs[off] = (byte)(n);
+            bs[++off] = (byte)(n >> 8);
+            bs[++off] = (byte)(n >> 16);
+            bs[++off] = (byte)(n >> 24);
+        }
+
+        private static void Encode56(ulong n, byte[] bs, int off)
+        {
+            Encode32((uint)n, bs, off);
+            Encode24((uint)(n >> 32), bs, off + 4);
+        }
+
+        private static void EncodePoint(PointExt p, byte[] r, int rOff)
+        {
+            uint[] x = X448Field.Create();
+            uint[] y = X448Field.Create();
+
+            X448Field.Inv(p.z, y);
+            X448Field.Mul(p.x, y, x);
+            X448Field.Mul(p.y, y, y);
+            X448Field.Normalize(x);
+            X448Field.Normalize(y);
+
+            X448Field.Encode(y, r, rOff);
+            r[rOff + PointBytes - 1] = (byte)((x[0] & 1) << 7);
+        }
+
+        public static void GeneratePublicKey(byte[] sk, int skOff, byte[] pk, int pkOff)
+        {
+            ShakeDigest d = new ShakeDigest(256);
+            byte[] h = new byte[ScalarBytes * 2];
+
+            d.BlockUpdate(sk, skOff, SecretKeySize);
+            d.DoFinal(h, 0, h.Length);
+
+            byte[] s = new byte[ScalarBytes];
+            PruneScalar(h, 0, s);
+
+            ScalarMultBaseEncoded(s, pk, pkOff);
+        }
+
+        private static sbyte[] GetWnaf(uint[] n, int width)
+        {
+            Debug.Assert(n[ScalarUints - 1] >> 31 == 0U);
+
+            uint[] t = new uint[ScalarUints * 2];
+            {
+                uint c = 0;
+                int tPos = t.Length, i = ScalarUints;
+                while (--i >= 0)
+                {
+                    uint next = n[i];
+                    t[--tPos] = (next >> 16) | (c << 16);
+                    t[--tPos] = c = next;
+                }
+            }
+
+            sbyte[] ws = new sbyte[448];
+
+            uint pow2 = 1U << width;
+            uint mask = pow2 - 1U;
+            uint sign = pow2 >> 1;
+
+            uint carry = 0U;
+            int j = 0;
+            for (int i = 0; i < t.Length; ++i, j -= 16)
+            {
+                uint word = t[i];
+                while (j < 16)
+                {
+                    uint word16 = word >> j;
+                    uint bit = word16 & 1U;
+
+                    if (bit == carry)
+                    {
+                        ++j;
+                        continue;
+                    }
+
+                    uint digit = (word16 & mask) + carry;
+                    carry = digit & sign;
+                    digit -= (carry << 1);
+                    carry >>= (width - 1);
+
+                    ws[(i << 4) + j] = (sbyte)digit;
+
+                    j += width;
+                }
+            }
+
+            Debug.Assert(carry == 0);
+
+            return ws;
+        }
+
+        private static void ImplSign(ShakeDigest d, byte[] h, byte[] s, byte[] pk, int pkOff, byte[] ctx, byte[] m, int mOff, int mLen, byte[] sig, int sigOff)
+        {
+            byte phflag = 0x00;
+
+            Dom4(d, phflag, ctx);
+            d.BlockUpdate(h, ScalarBytes, ScalarBytes);
+            d.BlockUpdate(m, mOff, mLen);
+            d.DoFinal(h, 0, h.Length);
+
+            byte[] r = ReduceScalar(h);
+            byte[] R = new byte[PointBytes];
+            ScalarMultBaseEncoded(r, R, 0);
+
+            Dom4(d, phflag, ctx);
+            d.BlockUpdate(R, 0, PointBytes);
+            d.BlockUpdate(pk, pkOff, PointBytes);
+            d.BlockUpdate(m, mOff, mLen);
+            d.DoFinal(h, 0, h.Length);
+
+            byte[] k = ReduceScalar(h);
+            byte[] S = CalculateS(r, k, s);
+
+            Array.Copy(R, 0, sig, sigOff, PointBytes);
+            Array.Copy(S, 0, sig, sigOff + PointBytes, ScalarBytes);
+        }
+
+        private static void PointAddVar(bool negate, PointExt p, PointExt r)
+        {
+            uint[] A = X448Field.Create();
+            uint[] B = X448Field.Create();
+            uint[] C = X448Field.Create();
+            uint[] D = X448Field.Create();
+            uint[] E = X448Field.Create();
+            uint[] F = X448Field.Create();
+            uint[] G = X448Field.Create();
+            uint[] H = X448Field.Create();
+
+            uint[] b, e, f, g;
+            if (negate)
+            {
+                b = E; e = B; f = G; g = F;
+                X448Field.Sub(p.y, p.x, H);
+            }
+            else
+            {
+                b = B; e = E; f = F; g = G;
+                X448Field.Add(p.y, p.x, H);
+            }
+
+            X448Field.Mul(p.z, r.z, A);
+            X448Field.Sqr(A, B);
+            X448Field.Mul(p.x, r.x, C);
+            X448Field.Mul(p.y, r.y, D);
+            X448Field.Mul(C, D, E);
+            X448Field.Mul(E, -C_d, E);
+    //        X448Field.Apm(B, E, F, G);
+            X448Field.Add(B, E, f);
+            X448Field.Sub(B, E, g);
+            X448Field.Add(r.x, r.y, E);
+            X448Field.Mul(H, E, H);
+    //        X448Field.Apm(D, C, B, E);
+            X448Field.Add(D, C, b);
+            X448Field.Sub(D, C, e);
+            X448Field.Carry(b);
+            X448Field.Sub(H, B, H);
+            X448Field.Mul(H, A, H);
+            X448Field.Mul(E, A, E);
+            X448Field.Mul(F, H, r.x);
+            X448Field.Mul(E, G, r.y);
+            X448Field.Mul(F, G, r.z);
+        }
+
+        private static void PointAddPrecomp(PointPrecomp p, PointExt r)
+        {
+            uint[] B = X448Field.Create();
+            uint[] C = X448Field.Create();
+            uint[] D = X448Field.Create();
+            uint[] E = X448Field.Create();
+            uint[] F = X448Field.Create();
+            uint[] G = X448Field.Create();
+            uint[] H = X448Field.Create();
+
+            X448Field.Sqr(r.z, B);
+            X448Field.Mul(p.x, r.x, C);
+            X448Field.Mul(p.y, r.y, D);
+            X448Field.Mul(C, D, E);
+            X448Field.Mul(E, -C_d, E);
+    //        X448Field.Apm(B, E, F, G);
+            X448Field.Add(B, E, F);
+            X448Field.Sub(B, E, G);
+            X448Field.Add(p.x, p.y, B);
+            X448Field.Add(r.x, r.y, E);
+            X448Field.Mul(B, E, H);
+    //        X448Field.Apm(D, C, B, E);
+            X448Field.Add(D, C, B);
+            X448Field.Sub(D, C, E);
+            X448Field.Carry(B);
+            X448Field.Sub(H, B, H);
+            X448Field.Mul(H, r.z, H);
+            X448Field.Mul(E, r.z, E);
+            X448Field.Mul(F, H, r.x);
+            X448Field.Mul(E, G, r.y);
+            X448Field.Mul(F, G, r.z);
+        }
+
+        private static PointExt PointCopy(PointExt p)
+        {
+            PointExt r = new PointExt();
+            X448Field.Copy(p.x, 0, r.x, 0);
+            X448Field.Copy(p.y, 0, r.y, 0);
+            X448Field.Copy(p.z, 0, r.z, 0);
+            return r;
+        }
+
+        private static void PointDouble(PointExt r)
+        {
+            uint[] B = X448Field.Create();
+            uint[] C = X448Field.Create();
+            uint[] D = X448Field.Create();
+            uint[] E = X448Field.Create();
+            uint[] H = X448Field.Create();
+            uint[] J = X448Field.Create();
+
+            X448Field.Add(r.x, r.y, B);
+            X448Field.Sqr(B, B);
+            X448Field.Sqr(r.x, C);
+            X448Field.Sqr(r.y, D);
+            X448Field.Add(C, D, E);
+            X448Field.Carry(E);
+            X448Field.Sqr(r.z, H);
+            X448Field.Add(H, H, H);
+            X448Field.Carry(H);
+            X448Field.Sub(E, H, J);
+            X448Field.Sub(B, E, B);
+            X448Field.Sub(C, D, C);
+            X448Field.Mul(B, J, r.x);
+            X448Field.Mul(E, C, r.y);
+            X448Field.Mul(E, J, r.z);
+        }
+
+        private static void PointExtendXY(PointExt p)
+        {
+            X448Field.One(p.z);
+        }
+
+        private static void PointLookup(int block, int index, PointPrecomp p)
+        {
+            Debug.Assert(0 <= block && block < PrecompBlocks);
+            Debug.Assert(0 <= index && index < PrecompPoints);
+
+            int off = block * PrecompPoints * 2 * X448Field.Size;
+
+            for (int i = 0; i < PrecompPoints; ++i)
+            {
+                int mask = ((i ^ index) - 1) >> 31;
+                Nat.CMov(X448Field.Size, mask, precompBase, off, p.x, 0);   off += X448Field.Size;
+                Nat.CMov(X448Field.Size, mask, precompBase, off, p.y, 0);   off += X448Field.Size;
+            }
+        }
+
+        private static PointExt[] PointPrecompVar(PointExt p, int count)
+        {
+            Debug.Assert(count > 0);
+
+            PointExt d = PointCopy(p);
+            PointDouble(d);
+
+            PointExt[] table = new PointExt[count];
+            table[0] = PointCopy(p);
+            for (int i = 1; i < count; ++i)
+            {
+                table[i] = PointCopy(table[i - 1]);
+                PointAddVar(false, d, table[i]);
+            }
+            return table;
+        }
+
+        private static void PointSetNeutral(PointExt p)
+        {
+            X448Field.Zero(p.x);
+            X448Field.One(p.y);
+            X448Field.One(p.z);
+        }
+
+        [MethodImpl(MethodImplOptions.Synchronized)]
+        public static void Precompute()
+        {
+            if (precompBase != null)
+            {
+                return;
+            }
+
+            PointExt p = new PointExt();
+            X448Field.Copy(B_x, 0, p.x, 0);
+            X448Field.Copy(B_y, 0, p.y, 0);
+            PointExtendXY(p);
+
+            precompBaseTable = PointPrecompVar(p, 1 << (WnafWidthBase - 2));
+
+            precompBase = new uint[PrecompBlocks * PrecompPoints * 2 * X448Field.Size];
+
+            int off = 0;
+            for (int b = 0; b < PrecompBlocks; ++b)
+            {
+                PointExt[] ds = new PointExt[PrecompTeeth];
+
+                PointExt sum = new PointExt();
+                PointSetNeutral(sum);
+
+                for (int t = 0; t < PrecompTeeth; ++t)
+                {
+                    PointAddVar(true, p, sum);
+                    PointDouble(p);
+
+                    ds[t] = PointCopy(p);
+
+                    for (int s = 1; s < PrecompSpacing; ++s)
+                    {
+                        PointDouble(p);
+                    }
+                }
+
+                PointExt[] points = new PointExt[PrecompPoints];
+                int k = 0;
+                points[k++] = sum;
+
+                for (int t = 0; t < (PrecompTeeth - 1); ++t)
+                {
+                    int size = 1 << t;
+                    for (int j = 0; j < size; ++j, ++k)
+                    {
+                        points[k] = PointCopy(points[k - size]);
+                        PointAddVar(false, ds[t], points[k]);
+                    }
+                }
+
+                Debug.Assert(k == PrecompPoints);
+
+                for (int i = 0; i < PrecompPoints; ++i)
+                {
+                    PointExt q = points[i];
+                    // TODO[ed448] Batch inversion
+                    X448Field.Inv(q.z, q.z);
+                    X448Field.Mul(q.x, q.z, q.x);
+                    X448Field.Mul(q.y, q.z, q.y);
+
+    //                X448Field.Normalize(q.x);
+    //                X448Field.Normalize(q.y);
+
+                    X448Field.Copy(q.x, 0, precompBase, off);   off += X448Field.Size;
+                    X448Field.Copy(q.y, 0, precompBase, off);   off += X448Field.Size;
+                }
+            }
+
+            Debug.Assert(off == precompBase.Length);
+        }
+
+        private static void PruneScalar(byte[] n, int nOff, byte[] r)
+        {
+            Array.Copy(n, nOff, r, 0, ScalarBytes);
+
+            r[0] &= 0xFC;
+            r[ScalarBytes - 2] |= 0x80;
+            r[ScalarBytes - 1] &= 0x00;
+        }
+
+        private static byte[] ReduceScalar(byte[] n)
+        {
+            ulong x00 =  Decode32(n,   0);          // x00:32/--
+            ulong x01 = (Decode24(n,   4) << 4);    // x01:28/--
+            ulong x02 =  Decode32(n,   7);          // x02:32/--
+            ulong x03 = (Decode24(n,  11) << 4);    // x03:28/--
+            ulong x04 =  Decode32(n,  14);          // x04:32/--
+            ulong x05 = (Decode24(n,  18) << 4);    // x05:28/--
+            ulong x06 =  Decode32(n,  21);          // x06:32/--
+            ulong x07 = (Decode24(n,  25) << 4);    // x07:28/--
+            ulong x08 =  Decode32(n,  28);          // x08:32/--
+            ulong x09 = (Decode24(n,  32) << 4);    // x09:28/--
+            ulong x10 =  Decode32(n,  35);          // x10:32/--
+            ulong x11 = (Decode24(n,  39) << 4);    // x11:28/--
+            ulong x12 =  Decode32(n,  42);          // x12:32/--
+            ulong x13 = (Decode24(n,  46) << 4);    // x13:28/--
+            ulong x14 =  Decode32(n,  49);          // x14:32/--
+            ulong x15 = (Decode24(n,  53) << 4);    // x15:28/--
+            ulong x16 =  Decode32(n,  56);          // x16:32/--
+            ulong x17 = (Decode24(n,  60) << 4);    // x17:28/--
+            ulong x18 =  Decode32(n,  63);          // x18:32/--
+            ulong x19 = (Decode24(n,  67) << 4);    // x19:28/--
+            ulong x20 =  Decode32(n,  70);          // x20:32/--
+            ulong x21 = (Decode24(n,  74) << 4);    // x21:28/--
+            ulong x22 =  Decode32(n,  77);          // x22:32/--
+            ulong x23 = (Decode24(n,  81) << 4);    // x23:28/--
+            ulong x24 =  Decode32(n,  84);          // x24:32/--
+            ulong x25 = (Decode24(n,  88) << 4);    // x25:28/--
+            ulong x26 =  Decode32(n,  91);          // x26:32/--
+            ulong x27 = (Decode24(n,  95) << 4);    // x27:28/--
+            ulong x28 =  Decode32(n,  98);          // x28:32/--
+            ulong x29 = (Decode24(n, 102) << 4);    // x29:28/--
+            ulong x30 =  Decode32(n, 105);          // x30:32/--
+            ulong x31 = (Decode24(n, 109) << 4);    // x31:28/--
+            ulong x32 =  Decode16(n, 112);          // x32:16/--
+
+    //        x32 += (x31 >> 28); x31 &= M28UL;
+            x16 += x32 * L4_0;                          // x16:42/--
+            x17 += x32 * L4_1;                          // x17:41/28
+            x18 += x32 * L4_2;                          // x18:43/42
+            x19 += x32 * L4_3;                          // x19:44/28
+            x20 += x32 * L4_4;                          // x20:43/--
+            x21 += x32 * L4_5;                          // x21:44/28
+            x22 += x32 * L4_6;                          // x22:43/41
+            x23 += x32 * L4_7;                          // x23:45/41
+
+            x31 += (x30 >> 28); x30 &= M28UL;           // x31:28/--, x30:28/--
+            x15 += x31 * L4_0;                          // x15:54/--
+            x16 += x31 * L4_1;                          // x16:53/42
+            x17 += x31 * L4_2;                          // x17:55/54
+            x18 += x31 * L4_3;                          // x18:56/44
+            x19 += x31 * L4_4;                          // x19:55/--
+            x20 += x31 * L4_5;                          // x20:56/43
+            x21 += x31 * L4_6;                          // x21:55/53
+            x22 += x31 * L4_7;                          // x22:57/53
+
+    //        x30 += (x29 >> 28); x29 &= M28UL;
+            x14 += x30 * L4_0;                          // x14:54/--
+            x15 += x30 * L4_1;                          // x15:54/53
+            x16 += x30 * L4_2;                          // x16:56/--
+            x17 += x30 * L4_3;                          // x17:57/--
+            x18 += x30 * L4_4;                          // x18:56/55
+            x19 += x30 * L4_5;                          // x19:56/55
+            x20 += x30 * L4_6;                          // x20:57/--
+            x21 += x30 * L4_7;                          // x21:57/56
+
+            x29 += (x28 >> 28); x28 &= M28UL;           // x29:28/--, x28:28/--
+            x13 += x29 * L4_0;                          // x13:54/--
+            x14 += x29 * L4_1;                          // x14:54/53
+            x15 += x29 * L4_2;                          // x15:56/--
+            x16 += x29 * L4_3;                          // x16:57/--
+            x17 += x29 * L4_4;                          // x17:57/55
+            x18 += x29 * L4_5;                          // x18:57/55
+            x19 += x29 * L4_6;                          // x19:57/52
+            x20 += x29 * L4_7;                          // x20:58/52
+
+    //        x28 += (x27 >> 28); x27 &= M28UL;
+            x12 += x28 * L4_0;                          // x12:54/--
+            x13 += x28 * L4_1;                          // x13:54/53
+            x14 += x28 * L4_2;                          // x14:56/--
+            x15 += x28 * L4_3;                          // x15:57/--
+            x16 += x28 * L4_4;                          // x16:57/55
+            x17 += x28 * L4_5;                          // x17:58/--
+            x18 += x28 * L4_6;                          // x18:58/--
+            x19 += x28 * L4_7;                          // x19:58/53
+
+            x27 += (x26 >> 28); x26 &= M28UL;           // x27:28/--, x26:28/--
+            x11 += x27 * L4_0;                          // x11:54/--
+            x12 += x27 * L4_1;                          // x12:54/53
+            x13 += x27 * L4_2;                          // x13:56/--
+            x14 += x27 * L4_3;                          // x14:57/--
+            x15 += x27 * L4_4;                          // x15:57/55
+            x16 += x27 * L4_5;                          // x16:58/--
+            x17 += x27 * L4_6;                          // x17:58/56
+            x18 += x27 * L4_7;                          // x18:59/--
+
+    //        x26 += (x25 >> 28); x25 &= M28UL;
+            x10 += x26 * L4_0;                          // x10:54/--
+            x11 += x26 * L4_1;                          // x11:54/53
+            x12 += x26 * L4_2;                          // x12:56/--
+            x13 += x26 * L4_3;                          // x13:57/--
+            x14 += x26 * L4_4;                          // x14:57/55
+            x15 += x26 * L4_5;                          // x15:58/--
+            x16 += x26 * L4_6;                          // x16:58/56
+            x17 += x26 * L4_7;                          // x17:59/--
+
+            x25 += (x24 >> 28); x24 &= M28UL;           // x25:28/--, x24:28/--
+            x09 += x25 * L4_0;                          // x09:54/--
+            x10 += x25 * L4_1;                          // x10:54/53
+            x11 += x25 * L4_2;                          // x11:56/--
+            x12 += x25 * L4_3;                          // x12:57/--
+            x13 += x25 * L4_4;                          // x13:57/55
+            x14 += x25 * L4_5;                          // x14:58/--
+            x15 += x25 * L4_6;                          // x15:58/56
+            x16 += x25 * L4_7;                          // x16:59/--
+
+            x21 += (x20 >> 28); x20 &= M28UL;           // x21:58/--, x20:28/--
+            x22 += (x21 >> 28); x21 &= M28UL;           // x22:57/54, x21:28/--
+            x23 += (x22 >> 28); x22 &= M28UL;           // x23:45/42, x22:28/--
+            x24 += (x23 >> 28); x23 &= M28UL;           // x24:28/18, x23:28/--
+
+            x08 += x24 * L4_0;                          // x08:54/--
+            x09 += x24 * L4_1;                          // x09:55/--
+            x10 += x24 * L4_2;                          // x10:56/46
+            x11 += x24 * L4_3;                          // x11:57/46
+            x12 += x24 * L4_4;                          // x12:57/55
+            x13 += x24 * L4_5;                          // x13:58/--
+            x14 += x24 * L4_6;                          // x14:58/56
+            x15 += x24 * L4_7;                          // x15:59/--
+
+            x07 += x23 * L4_0;                          // x07:54/--
+            x08 += x23 * L4_1;                          // x08:54/53
+            x09 += x23 * L4_2;                          // x09:56/53
+            x10 += x23 * L4_3;                          // x10:57/46
+            x11 += x23 * L4_4;                          // x11:57/55
+            x12 += x23 * L4_5;                          // x12:58/--
+            x13 += x23 * L4_6;                          // x13:58/56
+            x14 += x23 * L4_7;                          // x14:59/--
+
+            x06 += x22 * L4_0;                          // x06:54/--
+            x07 += x22 * L4_1;                          // x07:54/53
+            x08 += x22 * L4_2;                          // x08:56/--
+            x09 += x22 * L4_3;                          // x09:57/53
+            x10 += x22 * L4_4;                          // x10:57/55
+            x11 += x22 * L4_5;                          // x11:58/--
+            x12 += x22 * L4_6;                          // x12:58/56
+            x13 += x22 * L4_7;                          // x13:59/--
+
+            x18 += (x17 >> 28); x17 &= M28UL;           // x18:59/31, x17:28/--
+            x19 += (x18 >> 28); x18 &= M28UL;           // x19:58/54, x18:28/--
+            x20 += (x19 >> 28); x19 &= M28UL;           // x20:30/29, x19:28/--
+            x21 += (x20 >> 28); x20 &= M28UL;           // x21:28/03, x20:28/--
+
+            x05 += x21 * L4_0;                          // x05:54/--
+            x06 += x21 * L4_1;                          // x06:55/--
+            x07 += x21 * L4_2;                          // x07:56/31
+            x08 += x21 * L4_3;                          // x08:57/31
+            x09 += x21 * L4_4;                          // x09:57/56
+            x10 += x21 * L4_5;                          // x10:58/--
+            x11 += x21 * L4_6;                          // x11:58/56
+            x12 += x21 * L4_7;                          // x12:59/--
+
+            x04 += x20 * L4_0;                          // x04:54/--
+            x05 += x20 * L4_1;                          // x05:54/53
+            x06 += x20 * L4_2;                          // x06:56/53
+            x07 += x20 * L4_3;                          // x07:57/31
+            x08 += x20 * L4_4;                          // x08:57/55
+            x09 += x20 * L4_5;                          // x09:58/--
+            x10 += x20 * L4_6;                          // x10:58/56
+            x11 += x20 * L4_7;                          // x11:59/--
+
+            x03 += x19 * L4_0;                          // x03:54/--
+            x04 += x19 * L4_1;                          // x04:54/53
+            x05 += x19 * L4_2;                          // x05:56/--
+            x06 += x19 * L4_3;                          // x06:57/53
+            x07 += x19 * L4_4;                          // x07:57/55
+            x08 += x19 * L4_5;                          // x08:58/--
+            x09 += x19 * L4_6;                          // x09:58/56
+            x10 += x19 * L4_7;                          // x10:59/--
+
+            x15 += (x14 >> 28); x14 &= M28UL;           // x15:59/31, x14:28/--
+            x16 += (x15 >> 28); x15 &= M28UL;           // x16:59/32, x15:28/--
+            x17 += (x16 >> 28); x16 &= M28UL;           // x17:31/29, x16:28/--
+            x18 += (x17 >> 28); x17 &= M28UL;           // x18:28/04, x17:28/--
+
+            x02 += x18 * L4_0;                          // x02:54/--
+            x03 += x18 * L4_1;                          // x03:55/--
+            x04 += x18 * L4_2;                          // x04:56/32
+            x05 += x18 * L4_3;                          // x05:57/32
+            x06 += x18 * L4_4;                          // x06:57/56
+            x07 += x18 * L4_5;                          // x07:58/--
+            x08 += x18 * L4_6;                          // x08:58/56
+            x09 += x18 * L4_7;                          // x09:59/--
+
+            x01 += x17 * L4_0;                          // x01:54/--
+            x02 += x17 * L4_1;                          // x02:54/53
+            x03 += x17 * L4_2;                          // x03:56/53
+            x04 += x17 * L4_3;                          // x04:57/32
+            x05 += x17 * L4_4;                          // x05:57/55
+            x06 += x17 * L4_5;                          // x06:58/--
+            x07 += x17 * L4_6;                          // x07:58/56
+            x08 += x17 * L4_7;                          // x08:59/--
+
+            x16 *= 4;
+            x16 += (x15 >> 26); x15 &= M26UL;
+            x16 += 1;                                   // x16:30/01
+
+            x00 += x16 * L_0;
+            x01 += x16 * L_1;
+            x02 += x16 * L_2;
+            x03 += x16 * L_3;
+            x04 += x16 * L_4;
+            x05 += x16 * L_5;
+            x06 += x16 * L_6;
+            x07 += x16 * L_7;
+
+            x01 += (x00 >> 28); x00 &= M28UL;
+            x02 += (x01 >> 28); x01 &= M28UL;
+            x03 += (x02 >> 28); x02 &= M28UL;
+            x04 += (x03 >> 28); x03 &= M28UL;
+            x05 += (x04 >> 28); x04 &= M28UL;
+            x06 += (x05 >> 28); x05 &= M28UL;
+            x07 += (x06 >> 28); x06 &= M28UL;
+            x08 += (x07 >> 28); x07 &= M28UL;
+            x09 += (x08 >> 28); x08 &= M28UL;
+            x10 += (x09 >> 28); x09 &= M28UL;
+            x11 += (x10 >> 28); x10 &= M28UL;
+            x12 += (x11 >> 28); x11 &= M28UL;
+            x13 += (x12 >> 28); x12 &= M28UL;
+            x14 += (x13 >> 28); x13 &= M28UL;
+            x15 += (x14 >> 28); x14 &= M28UL;
+            x16  = (x15 >> 26); x15 &= M26UL;
+
+            x16 -= 1;
+
+            Debug.Assert(x16 == 0UL || x16 == ulong.MaxValue);
+
+            x00 -= x16 & L_0;
+            x01 -= x16 & L_1;
+            x02 -= x16 & L_2;
+            x03 -= x16 & L_3;
+            x04 -= x16 & L_4;
+            x05 -= x16 & L_5;
+            x06 -= x16 & L_6;
+            x07 -= x16 & L_7;
+
+            x01 += (ulong)((long)x00 >> 28); x00 &= M28UL;
+            x02 += (ulong)((long)x01 >> 28); x01 &= M28UL;
+            x03 += (ulong)((long)x02 >> 28); x02 &= M28UL;
+            x04 += (ulong)((long)x03 >> 28); x03 &= M28UL;
+            x05 += (ulong)((long)x04 >> 28); x04 &= M28UL;
+            x06 += (ulong)((long)x05 >> 28); x05 &= M28UL;
+            x07 += (ulong)((long)x06 >> 28); x06 &= M28UL;
+            x08 += (ulong)((long)x07 >> 28); x07 &= M28UL;
+            x09 += (ulong)((long)x08 >> 28); x08 &= M28UL;
+            x10 += (ulong)((long)x09 >> 28); x09 &= M28UL;
+            x11 += (ulong)((long)x10 >> 28); x10 &= M28UL;
+            x12 += (ulong)((long)x11 >> 28); x11 &= M28UL;
+            x13 += (ulong)((long)x12 >> 28); x12 &= M28UL;
+            x14 += (ulong)((long)x13 >> 28); x13 &= M28UL;
+            x15 += (ulong)((long)x14 >> 28); x14 &= M28UL;
+
+            Debug.Assert(x15 >> 26 == 0UL);
+
+            byte[] r = new byte[ScalarBytes];
+            Encode56(x00 | (x01 << 28), r,  0);
+            Encode56(x02 | (x03 << 28), r,  7);
+            Encode56(x04 | (x05 << 28), r, 14);
+            Encode56(x06 | (x07 << 28), r, 21);
+            Encode56(x08 | (x09 << 28), r, 28);
+            Encode56(x10 | (x11 << 28), r, 35);
+            Encode56(x12 | (x13 << 28), r, 42);
+            Encode56(x14 | (x15 << 28), r, 49);
+    //        r[ScalarBytes - 1] = 0;
+            return r;
+        }
+
+        private static void ScalarMultBase(byte[] k, PointExt r)
+        {
+            Precompute();
+
+            PointSetNeutral(r);
+
+            uint[] n = new uint[ScalarUints + 1];
+            DecodeScalar(k, 0, n);
+
+            // Recode the scalar into signed-digit form
+            {
+                n[ScalarUints] = 4U + Nat.CAdd(ScalarUints, ~(int)n[0] & 1, n, L, n);
+                uint c = Nat.ShiftDownBit(n.Length, n, 0);
+                Debug.Assert(c == (1U << 31));
+            }
+
+            PointPrecomp p = new PointPrecomp();
+
+            int cOff = PrecompSpacing - 1;
+            for (;;)
+            {
+                int tPos = cOff;
+
+                for (int b = 0; b < PrecompBlocks; ++b)
+                {
+                    uint w = 0;
+                    for (int t = 0; t < PrecompTeeth; ++t)
+                    {
+                        uint tBit = (n[tPos >> 5] >> (tPos & 0x1F)) & 1U;
+                        w |= tBit << t;
+                        tPos += PrecompSpacing;
+                    }
+
+                    int sign = (int)(w >> (PrecompTeeth - 1)) & 1;
+                    int abs = ((int)w ^ -sign) & PrecompMask;
+
+                    Debug.Assert(sign == 0 || sign == 1);
+                    Debug.Assert(0 <= abs && abs < PrecompPoints);
+
+                    PointLookup(b, abs, p);
+
+                    X448Field.CNegate(sign, p.x);
+
+                    PointAddPrecomp(p, r);
+                }
+
+                if (--cOff < 0)
+                {
+                    break;
+                }
+
+                PointDouble(r);
+            }
+        }
+
+        private static void ScalarMultBaseEncoded(byte[] k, byte[] r, int rOff)
+        {
+            PointExt p = new PointExt();
+            ScalarMultBase(k, p);
+            EncodePoint(p, r, rOff);
+        }
+
+        private static void ScalarMultStraussVar(uint[] nb, uint[] np, PointExt p, PointExt r)
+        {
+            Precompute();
+
+            int width = 5;
+
+            sbyte[] ws_b = GetWnaf(nb, WnafWidthBase);
+            sbyte[] ws_p = GetWnaf(np, width);
+
+            PointExt[] tp = PointPrecompVar(p, 1 << (width - 2));
+
+            PointSetNeutral(r);
+
+            int bit = 447;
+            while (bit > 0 && (ws_b[bit] | ws_p[bit]) == 0)
+            {
+                --bit;
+            }
+
+            for (;;)
+            {
+                int wb = ws_b[bit];
+                if (wb != 0)
+                {
+                    int sign = wb >> 31;
+                    int index = (wb ^ sign) >> 1;
+
+                    PointAddVar((sign != 0), precompBaseTable[index], r);
+                }
+
+                int wp = ws_p[bit];
+                if (wp != 0)
+                {
+                    int sign = wp >> 31;
+                    int index = (wp ^ sign) >> 1;
+
+                    PointAddVar((sign != 0), tp[index], r);
+                }
+
+                if (--bit < 0)
+                {
+                    break;
+                }
+
+                PointDouble(r);
+            }
+        }
+
+        public static void Sign(byte[] sk, int skOff, byte[] ctx, byte[] m, int mOff, int mLen, byte[] sig, int sigOff)
+        {
+            if (!CheckContextVar(ctx))
+            {
+                throw new ArgumentException("ctx");
+            }
+
+            ShakeDigest d = new ShakeDigest(256);
+            byte[] h = new byte[ScalarBytes * 2];
+
+            d.BlockUpdate(sk, skOff, SecretKeySize);
+            d.DoFinal(h, 0, h.Length);
+
+            byte[] s = new byte[ScalarBytes];
+            PruneScalar(h, 0, s);
+
+            byte[] pk = new byte[PointBytes];
+            ScalarMultBaseEncoded(s, pk, 0);
+
+            ImplSign(d, h, s, pk, 0, ctx, m, mOff, mLen, sig, sigOff);
+        }
+
+        public static void Sign(byte[] sk, int skOff, byte[] pk, int pkOff, byte[] ctx, byte[] m, int mOff, int mLen, byte[] sig, int sigOff)
+        {
+            if (!CheckContextVar(ctx))
+            {
+                throw new ArgumentException("ctx");
+            }
+
+            ShakeDigest d = new ShakeDigest(256);
+            byte[] h = new byte[ScalarBytes * 2];
+
+            d.BlockUpdate(sk, skOff, SecretKeySize);
+            d.DoFinal(h, 0, h.Length);
+
+            byte[] s = new byte[ScalarBytes];
+            PruneScalar(h, 0, s);
+
+            ImplSign(d, h, s, pk, pkOff, ctx, m, mOff, mLen, sig, sigOff);
+        }
+
+        public static bool Verify(byte[] sig, int sigOff, byte[] pk, int pkOff, byte[] ctx, byte[] m, int mOff, int mLen)
+        {
+            if (!CheckContextVar(ctx))
+            {
+                throw new ArgumentException("ctx");
+            }
+
+            byte[] R = Arrays.CopyOfRange(sig, sigOff, sigOff + PointBytes);
+            byte[] S = Arrays.CopyOfRange(sig, sigOff + PointBytes, sigOff + SignatureSize);
+
+            if (!CheckPointVar(R))
+            {
+                return false;
+            }
+            if (!CheckScalarVar(S))
+            {
+                return false;
+            }
+
+            PointExt pA = new PointExt();
+            if (!DecodePointVar(pk, pkOff, true, pA))
+            {
+                return false;
+            }
+
+            byte phflag = 0x00;
+
+            ShakeDigest d = new ShakeDigest(256);
+            byte[] h = new byte[ScalarBytes * 2];
+
+            Dom4(d, phflag, ctx);
+            d.BlockUpdate(R, 0, PointBytes);
+            d.BlockUpdate(pk, pkOff, PointBytes);
+            d.BlockUpdate(m, mOff, mLen);
+            d.DoFinal(h, 0, h.Length);
+
+            byte[] k = ReduceScalar(h);
+
+            uint[] nS = new uint[ScalarUints];
+            DecodeScalar(S, 0, nS);
+
+            uint[] nA = new uint[ScalarUints];
+            DecodeScalar(k, 0, nA);
+
+            PointExt pR = new PointExt();
+            ScalarMultStraussVar(nS, nA, pA, pR);
+
+            byte[] check = new byte[PointBytes];
+            EncodePoint(pR, check, 0);
+
+            return Arrays.AreEqual(check, R);
+        }
+    }
+}
diff --git a/crypto/src/math/raw/Interleave.cs b/crypto/src/math/raw/Interleave.cs
index d21840644..591ba3f15 100644
--- a/crypto/src/math/raw/Interleave.cs
+++ b/crypto/src/math/raw/Interleave.cs
@@ -6,6 +6,7 @@ namespace Org.BouncyCastle.Math.Raw
     {
         private const ulong M32 = 0x55555555UL;
         private const ulong M64 = 0x5555555555555555UL;
+        private const ulong M64R = 0xAAAAAAAAAAAAAAAAUL;
 
         /*
          * This expands 8 bit indices into 16 bit contents (high bit 14), by inserting 0s between bits.
@@ -92,6 +93,65 @@ namespace Org.BouncyCastle.Math.Raw
             z[zOff + 1] = (x >> 1) & M64;
         }
 
+        internal static void Expand64To128Rev(ulong x, ulong[] z, int zOff)
+        {
+            // "shuffle" low half to even bits and high half to odd bits
+            ulong t;
+            t = (x ^ (x >> 16)) & 0x00000000FFFF0000UL; x ^= (t ^ (t << 16));
+            t = (x ^ (x >>  8)) & 0x0000FF000000FF00UL; x ^= (t ^ (t <<  8));
+            t = (x ^ (x >>  4)) & 0x00F000F000F000F0UL; x ^= (t ^ (t <<  4));
+            t = (x ^ (x >>  2)) & 0x0C0C0C0C0C0C0C0CUL; x ^= (t ^ (t <<  2));
+            t = (x ^ (x >>  1)) & 0x2222222222222222UL; x ^= (t ^ (t <<  1));
+
+            z[zOff]     = (x     ) & M64R;
+            z[zOff + 1] = (x << 1) & M64R;
+        }
+
+        internal static uint Shuffle(uint x)
+        {
+            // "shuffle" low half to even bits and high half to odd bits
+            uint t;
+            t = (x ^ (x >> 8)) & 0x0000FF00U; x ^= (t ^ (t << 8));
+            t = (x ^ (x >> 4)) & 0x00F000F0U; x ^= (t ^ (t << 4));
+            t = (x ^ (x >> 2)) & 0x0C0C0C0CU; x ^= (t ^ (t << 2));
+            t = (x ^ (x >> 1)) & 0x22222222U; x ^= (t ^ (t << 1));
+            return x;
+        }
+
+        internal static ulong Shuffle(ulong x)
+        {
+            // "shuffle" low half to even bits and high half to odd bits
+            ulong t;
+            t = (x ^ (x >> 16)) & 0x00000000FFFF0000UL; x ^= (t ^ (t << 16));
+            t = (x ^ (x >>  8)) & 0x0000FF000000FF00UL; x ^= (t ^ (t <<  8));
+            t = (x ^ (x >>  4)) & 0x00F000F000F000F0UL; x ^= (t ^ (t <<  4));
+            t = (x ^ (x >>  2)) & 0x0C0C0C0C0C0C0C0CUL; x ^= (t ^ (t <<  2));
+            t = (x ^ (x >>  1)) & 0x2222222222222222UL; x ^= (t ^ (t <<  1));
+            return x;
+        }
+
+        internal static uint Shuffle2(uint x)
+        {
+            // "shuffle" (twice) low half to even bits and high half to odd bits
+            uint t;
+            t = (x ^ (x >>  7)) & 0x00AA00AAU; x ^= (t ^ (t <<  7));
+            t = (x ^ (x >> 14)) & 0x0000CCCCU; x ^= (t ^ (t << 14));
+            t = (x ^ (x >>  4)) & 0x00F000F0U; x ^= (t ^ (t <<  4));
+            t = (x ^ (x >>  8)) & 0x0000FF00U; x ^= (t ^ (t <<  8));
+            return x;
+        }
+
+        internal static uint Unshuffle(uint x)
+        {
+            // "unshuffle" even bits to low half and odd bits to high half
+            uint t;
+            t = (x ^ (x >> 1)) & 0x22222222U; x ^= (t ^ (t << 1));
+            t = (x ^ (x >> 2)) & 0x0C0C0C0CU; x ^= (t ^ (t << 2));
+            t = (x ^ (x >> 4)) & 0x00F000F0U; x ^= (t ^ (t << 4));
+            t = (x ^ (x >> 8)) & 0x0000FF00U; x ^= (t ^ (t << 8));
+            return x;
+        }
+
         internal static ulong Unshuffle(ulong x)
         {
             // "unshuffle" even bits to low half and odd bits to high half
@@ -103,5 +163,16 @@ namespace Org.BouncyCastle.Math.Raw
             t = (x ^ (x >> 16)) & 0x00000000FFFF0000UL; x ^= (t ^ (t << 16));
             return x;
         }
+
+        internal static uint Unshuffle2(uint x)
+        {
+            // "unshuffle" (twice) even bits to low half and odd bits to high half
+            uint t;
+            t = (x ^ (x >>  8)) & 0x0000FF00U; x ^= (t ^ (t <<  8));
+            t = (x ^ (x >>  4)) & 0x00F000F0U; x ^= (t ^ (t <<  4));
+            t = (x ^ (x >> 14)) & 0x0000CCCCU; x ^= (t ^ (t << 14));
+            t = (x ^ (x >>  7)) & 0x00AA00AAU; x ^= (t ^ (t <<  7));
+            return x;
+        }
     }
 }
diff --git a/crypto/src/math/raw/Nat.cs b/crypto/src/math/raw/Nat.cs
index cf6516c61..7ca60278a 100644
--- a/crypto/src/math/raw/Nat.cs
+++ b/crypto/src/math/raw/Nat.cs
@@ -195,6 +195,64 @@ namespace Org.BouncyCastle.Math.Raw
             return c == 0 ? 0 : IncAt(len, z, zOff, 1);
         }
 
+        public static uint CAdd(int len, int mask, uint[] x, uint[] y, uint[] z)
+        {
+            uint MASK = (uint)-(mask & 1);
+
+            ulong c = 0;
+            for (int i = 0; i < len; ++i)
+            {
+                c += (ulong)x[i] + (y[i] & MASK);
+                z[i] = (uint)c;
+                c >>= 32;
+            }
+            return (uint)c;
+        }
+
+        public static void CMov(int len, int mask, uint[] x, int xOff, uint[] z, int zOff)
+        {
+            uint MASK = (uint)-(mask & 1);
+
+            for (int i = 0; i < len; ++i)
+            {
+                uint z_i = z[zOff + i], diff = z_i ^ x[xOff + i];
+                z_i ^= (diff & MASK);
+                z[zOff + i] = z_i;
+            }
+
+            //uint half = 0x55555555U, rest = half << (-(int)MASK);
+
+            //for (int i = 0; i < len; ++i)
+            //{
+            //    uint z_i = z[zOff + i], diff = z_i ^ x[xOff + i];
+            //    z_i ^= (diff & half);
+            //    z_i ^= (diff & rest);
+            //    z[zOff + i] = z_i;
+            //}
+        }
+
+        public static void CMov(int len, int mask, int[] x, int xOff, int[] z, int zOff)
+        {
+            mask = -(mask & 1);
+
+            for (int i = 0; i < len; ++i)
+            {
+                int z_i = z[zOff + i], diff = z_i ^ x[xOff + i];
+                z_i ^= (diff & mask);
+                z[zOff + i] = z_i;
+            }
+
+            //int half = 0x55555555, rest = half << (-mask);
+
+            //for (int i = 0; i < len; ++i)
+            //{
+            //    int z_i = z[zOff + i], diff = z_i ^ x[xOff + i];
+            //    z_i ^= (diff & half);
+            //    z_i ^= (diff & rest);
+            //    z[zOff + i] = z_i;
+            //}
+        }
+
         public static void Copy(int len, uint[] x, uint[] z)
         {
             Array.Copy(x, 0, z, 0, len);
@@ -448,6 +506,33 @@ namespace Org.BouncyCastle.Math.Raw
             }
         }
 
+        public static uint MulAddTo(int len, uint[] x, uint[] y, uint[] zz)
+        {
+            ulong zc = 0;
+            for (int i = 0; i < len; ++i)
+            {
+                ulong c = MulWordAddTo(len, x[i], y, 0, zz, i) & M;
+                c += zc + (zz[i + len] & M);
+                zz[i + len] = (uint)c;
+                zc = c >> 32;
+            }
+            return (uint)zc;
+        }
+
+        public static uint MulAddTo(int len, uint[] x, int xOff, uint[] y, int yOff, uint[] zz, int zzOff)
+        {
+            ulong zc = 0;
+            for (int i = 0; i < len; ++i)
+            {
+                ulong c = MulWordAddTo(len, x[xOff + i], y, yOff, zz, zzOff) & M;
+                c += zc + (zz[zzOff + len] & M);
+                zz[zzOff + len] = (uint)c;
+                zc = c >> 32;
+                ++zzOff;
+            }
+            return (uint)zc;
+        }
+
         public static uint Mul31BothAdd(int len, uint a, uint[] x, uint b, uint[] y, uint[] z, int zOff)
         {
             ulong c = 0, aVal = (ulong)a, bVal = (ulong)b;
diff --git a/crypto/test/UnitTests.csproj b/crypto/test/UnitTests.csproj
index 8a72f148b..5f0e7af57 100644
--- a/crypto/test/UnitTests.csproj
+++ b/crypto/test/UnitTests.csproj
@@ -325,6 +325,8 @@
     <Compile Include="src\math\ec\custom\sec\test\SecP384R1FieldTest.cs" />
     <Compile Include="src\math\ec\rfc7748\test\X25519Test.cs" />
     <Compile Include="src\math\ec\rfc7748\test\X448Test.cs" />
+    <Compile Include="src\math\ec\rfc8032\test\Ed25519Test.cs" />
+    <Compile Include="src\math\ec\rfc8032\test\Ed448Test.cs" />
     <Compile Include="src\math\ec\test\AllTests.cs" />
     <Compile Include="src\math\ec\test\ECAlgorithmsTest.cs" />
     <Compile Include="src\math\ec\test\ECPointPerformanceTest.cs" />
diff --git a/crypto/test/src/math/ec/rfc8032/test/Ed25519Test.cs b/crypto/test/src/math/ec/rfc8032/test/Ed25519Test.cs
new file mode 100644
index 000000000..43ea23988
--- /dev/null
+++ b/crypto/test/src/math/ec/rfc8032/test/Ed25519Test.cs
@@ -0,0 +1,231 @@
+using System;
+
+using NUnit.Framework;
+
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.Utilities;
+using Org.BouncyCastle.Utilities.Encoders;
+
+namespace Org.BouncyCastle.Math.EC.Rfc8032.Tests
+{
+    [TestFixture]
+    public class Ed25519Test
+    {
+		private static readonly SecureRandom Random = new SecureRandom();
+      
+		[SetUp]
+        public void SetUp()
+        {
+            Ed25519.Precompute();
+        }
+
+		[Test]
+        public void TestEd25519Consistency()
+        {
+            byte[] sk = new byte[Ed25519.SecretKeySize];
+            byte[] pk = new byte[Ed25519.PublicKeySize];
+            byte[] m = new byte[255];
+            byte[] sig1 = new byte[Ed25519.SignatureSize];
+			byte[] sig2 = new byte[Ed25519.SignatureSize];
+
+			Random.NextBytes(m);
+
+            for (int i = 0; i < 10; ++i)
+            {
+				Random.NextBytes(sk);
+                Ed25519.GeneratePublicKey(sk, 0, pk, 0);
+
+                int mLen = Random.Next() & 255;
+
+                Ed25519.Sign(sk, 0, m, 0, mLen, sig1, 0);
+                Ed25519.Sign(sk, 0, pk, 0, m, 0, mLen, sig2, 0);
+
+                Assert.IsTrue(Arrays.AreEqual(sig1, sig2), "Consistent signatures #" + i);
+
+                bool shouldVerify = Ed25519.Verify(sig1, 0, pk, 0, m, 0, mLen);
+
+                Assert.IsTrue(shouldVerify, "Consistent sign/verify #" + i);
+
+                sig1[Ed25519.PublicKeySize - 1] ^= 0x80;
+                bool shouldNotVerify = Ed25519.Verify(sig1, 0, pk, 0, m, 0, mLen);
+
+                Assert.IsFalse(shouldNotVerify, "Consistent verification failure #" + i);
+            }
+        }
+
+        [Test]
+		public void TestEd25519Vector1()
+        {
+            CheckEd25519Vector(
+                ("9d61b19deffd5a60ba844af492ec2cc4"
+                + "4449c5697b326919703bac031cae7f60"),
+                ("d75a980182b10ab7d54bfed3c964073a"
+                + "0ee172f3daa62325af021a68f707511a"),
+                "",
+                ("e5564300c360ac729086e2cc806e828a"
+                + "84877f1eb8e5d974d873e06522490155"
+                + "5fb8821590a33bacc61e39701cf9b46b"
+                + "d25bf5f0595bbe24655141438e7a100b"),
+                "Ed25519 Vector #1");
+        }
+      
+		[Test]
+        public void TestEd25519Vector2()
+        {
+            CheckEd25519Vector(
+                ("4ccd089b28ff96da9db6c346ec114e0f"
+                + "5b8a319f35aba624da8cf6ed4fb8a6fb"),
+                ("3d4017c3e843895a92b70aa74d1b7ebc"
+                + "9c982ccf2ec4968cc0cd55f12af4660c"),
+                "72",
+                ("92a009a9f0d4cab8720e820b5f642540"
+                + "a2b27b5416503f8fb3762223ebdb69da"
+                + "085ac1e43e15996e458f3613d0f11d8c"
+                + "387b2eaeb4302aeeb00d291612bb0c00"),
+                "Ed25519 Vector #2");
+        }
+      
+		[Test]
+        public void TestEd25519Vector3()
+        {
+            CheckEd25519Vector(
+                ("c5aa8df43f9f837bedb7442f31dcb7b1"
+                + "66d38535076f094b85ce3a2e0b4458f7"),
+                ("fc51cd8e6218a1a38da47ed00230f058"
+                + "0816ed13ba3303ac5deb911548908025"),
+                "af82",
+                ("6291d657deec24024827e69c3abe01a3"
+                + "0ce548a284743a445e3680d7db5ac3ac"
+                + "18ff9b538d16f290ae67f760984dc659"
+                + "4a7c15e9716ed28dc027beceea1ec40a"),
+                "Ed25519 Vector #3");
+        }
+
+        [Test]
+        public void TestEd25519Vector1023()
+        {
+            string m =
+                "08b8b2b733424243760fe426a4b54908" +
+                "632110a66c2f6591eabd3345e3e4eb98" +
+                "fa6e264bf09efe12ee50f8f54e9f77b1" +
+                "e355f6c50544e23fb1433ddf73be84d8" +
+                "79de7c0046dc4996d9e773f4bc9efe57" +
+                "38829adb26c81b37c93a1b270b20329d" +
+                "658675fc6ea534e0810a4432826bf58c" +
+                "941efb65d57a338bbd2e26640f89ffbc" +
+                "1a858efcb8550ee3a5e1998bd177e93a" +
+                "7363c344fe6b199ee5d02e82d522c4fe" +
+                "ba15452f80288a821a579116ec6dad2b" +
+                "3b310da903401aa62100ab5d1a36553e" +
+                "06203b33890cc9b832f79ef80560ccb9" +
+                "a39ce767967ed628c6ad573cb116dbef" +
+                "efd75499da96bd68a8a97b928a8bbc10" +
+                "3b6621fcde2beca1231d206be6cd9ec7" +
+                "aff6f6c94fcd7204ed3455c68c83f4a4" +
+                "1da4af2b74ef5c53f1d8ac70bdcb7ed1" +
+                "85ce81bd84359d44254d95629e9855a9" +
+                "4a7c1958d1f8ada5d0532ed8a5aa3fb2" +
+                "d17ba70eb6248e594e1a2297acbbb39d" +
+                "502f1a8c6eb6f1ce22b3de1a1f40cc24" +
+                "554119a831a9aad6079cad88425de6bd" +
+                "e1a9187ebb6092cf67bf2b13fd65f270" +
+                "88d78b7e883c8759d2c4f5c65adb7553" +
+                "878ad575f9fad878e80a0c9ba63bcbcc" +
+                "2732e69485bbc9c90bfbd62481d9089b" +
+                "eccf80cfe2df16a2cf65bd92dd597b07" +
+                "07e0917af48bbb75fed413d238f5555a" +
+                "7a569d80c3414a8d0859dc65a46128ba" +
+                "b27af87a71314f318c782b23ebfe808b" +
+                "82b0ce26401d2e22f04d83d1255dc51a" +
+                "ddd3b75a2b1ae0784504df543af8969b" +
+                "e3ea7082ff7fc9888c144da2af58429e" +
+                "c96031dbcad3dad9af0dcbaaaf268cb8" +
+                "fcffead94f3c7ca495e056a9b47acdb7" +
+                "51fb73e666c6c655ade8297297d07ad1" +
+                "ba5e43f1bca32301651339e22904cc8c" +
+                "42f58c30c04aafdb038dda0847dd988d" +
+                "cda6f3bfd15c4b4c4525004aa06eeff8" +
+                "ca61783aacec57fb3d1f92b0fe2fd1a8" +
+                "5f6724517b65e614ad6808d6f6ee34df" +
+                "f7310fdc82aebfd904b01e1dc54b2927" +
+                "094b2db68d6f903b68401adebf5a7e08" +
+                "d78ff4ef5d63653a65040cf9bfd4aca7" +
+                "984a74d37145986780fc0b16ac451649" +
+                "de6188a7dbdf191f64b5fc5e2ab47b57" +
+                "f7f7276cd419c17a3ca8e1b939ae49e4" +
+                "88acba6b965610b5480109c8b17b80e1" +
+                "b7b750dfc7598d5d5011fd2dcc5600a3" +
+                "2ef5b52a1ecc820e308aa342721aac09" +
+                "43bf6686b64b2579376504ccc493d97e" +
+                "6aed3fb0f9cd71a43dd497f01f17c0e2" +
+                "cb3797aa2a2f256656168e6c496afc5f" +
+                "b93246f6b1116398a346f1a641f3b041" +
+                "e989f7914f90cc2c7fff357876e506b5" +
+                "0d334ba77c225bc307ba537152f3f161" +
+                "0e4eafe595f6d9d90d11faa933a15ef1" +
+                "369546868a7f3a45a96768d40fd9d034" +
+                "12c091c6315cf4fde7cb68606937380d" +
+                "b2eaaa707b4c4185c32eddcdd306705e" +
+                "4dc1ffc872eeee475a64dfac86aba41c" +
+                "0618983f8741c5ef68d3a101e8a3b8ca" +
+                "c60c905c15fc910840b94c00a0b9d0";
+
+            CheckEd25519Vector(
+                ("f5e5767cf153319517630f226876b86c"
+                + "8160cc583bc013744c6bf255f5cc0ee5"),
+                ("278117fc144c72340f67d0f2316e8386"
+                + "ceffbf2b2428c9c51fef7c597f1d426e"),
+                m,
+                ("0aab4c900501b3e24d7cdf4663326a3a"
+                + "87df5e4843b2cbdb67cbf6e460fec350"
+                + "aa5371b1508f9f4528ecea23c436d94b"
+                + "5e8fcd4f681e30a6ac00a9704a188a03"),
+                "Ed25519 Vector #1023");
+        }
+
+        [Test]
+        public void TestEd25519VectorSHAabc()
+        {
+            CheckEd25519Vector(
+                ("833fe62409237b9d62ec77587520911e"
+                + "9a759cec1d19755b7da901b96dca3d42"),
+                ("ec172b93ad5e563bf4932c70e1245034"
+                + "c35467ef2efd4d64ebf819683467e2bf"),
+                ("ddaf35a193617abacc417349ae204131"
+                + "12e6fa4e89a97ea20a9eeee64b55d39a"
+                + "2192992a274fc1a836ba3c23a3feebbd"
+                + "454d4423643ce80e2a9ac94fa54ca49f"),
+                ("dc2a4459e7369633a52b1bf277839a00"
+                + "201009a3efbf3ecb69bea2186c26b589"
+                + "09351fc9ac90b3ecfdfbc7c66431e030"
+                + "3dca179c138ac17ad9bef1177331a704"),
+                "Ed25519 Vector SHA(abc)");
+        }
+      
+        private static void CheckEd25519Vector(string sSK, string sPK, string sM, string sSig, string text)
+        {
+            byte[] sk = Hex.Decode(sSK);
+
+            byte[] pk = Hex.Decode(sPK);
+            byte[] pkGen = new byte[Ed25519.PublicKeySize];
+            Ed25519.GeneratePublicKey(sk, 0, pkGen, 0);
+            Assert.IsTrue(Arrays.AreEqual(pk, pkGen), text);
+         
+			byte[] m = Hex.Decode(sM);
+            byte[] sig = Hex.Decode(sSig);
+            byte[] sigGen = new byte[Ed25519.SignatureSize];
+            Ed25519.Sign(sk, 0, m, 0, m.Length, sigGen, 0);
+            Assert.IsTrue(Arrays.AreEqual(sig, sigGen), text);
+
+            Ed25519.Sign(sk, 0, pk, 0, m, 0, m.Length, sigGen, 0);
+            Assert.IsTrue(Arrays.AreEqual(sig, sigGen), text);
+
+            bool shouldVerify = Ed25519.Verify(sig, 0, pk, 0, m, 0, m.Length);
+            Assert.IsTrue(shouldVerify, text);
+
+			sig[Ed25519.SignatureSize - 1] ^= 0x80;
+            bool shouldNotVerify = Ed25519.Verify(sig, 0, pk, 0, m, 0, m.Length);
+            Assert.IsFalse(shouldNotVerify, text);
+        }
+    }
+}
diff --git a/crypto/test/src/math/ec/rfc8032/test/Ed448Test.cs b/crypto/test/src/math/ec/rfc8032/test/Ed448Test.cs
new file mode 100644
index 000000000..98c487c09
--- /dev/null
+++ b/crypto/test/src/math/ec/rfc8032/test/Ed448Test.cs
@@ -0,0 +1,400 @@
+using System;
+
+using NUnit.Framework;
+
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.Utilities;
+using Org.BouncyCastle.Utilities.Encoders;
+
+namespace Org.BouncyCastle.Math.EC.Rfc8032.Tests
+{
+    [TestFixture]
+    public class Ed448Test
+    {
+        private static readonly SecureRandom Random = new SecureRandom();
+
+        [SetUp]
+        public void SetUp()
+        {
+            Ed448.Precompute();
+        }
+
+        [Test]
+        public void TestEd448Consistency()
+        {
+            byte[] sk = new byte[Ed448.SecretKeySize];
+            byte[] pk = new byte[Ed448.PublicKeySize];
+            byte[] ctx = new byte[Random.Next() & 7];
+            byte[] m = new byte[255];
+            byte[] sig1 = new byte[Ed448.SignatureSize];
+            byte[] sig2 = new byte[Ed448.SignatureSize];
+
+            Random.NextBytes(ctx);
+            Random.NextBytes(m);
+
+            for (int i = 0; i < 10; ++i)
+            {
+                Random.NextBytes(sk);
+                Ed448.GeneratePublicKey(sk, 0, pk, 0);
+
+                int mLen = Random.Next() & 255;
+
+                Ed448.Sign(sk, 0, ctx, m, 0, mLen, sig1, 0);
+                Ed448.Sign(sk, 0, pk, 0, ctx, m, 0, mLen, sig2, 0);
+
+                Assert.IsTrue(Arrays.AreEqual(sig1, sig2), "Consistent signatures #" + i);
+
+                bool shouldVerify = Ed448.Verify(sig1, 0, pk, 0, ctx, m, 0, mLen);
+
+                Assert.IsTrue(shouldVerify, "Consistent sign/verify #" + i);
+
+                sig1[Ed448.PublicKeySize - 1] ^= 0x80;
+                bool shouldNotVerify = Ed448.Verify(sig1, 0, pk, 0, ctx, m, 0, mLen);
+
+                Assert.IsFalse(shouldNotVerify, "Consistent verification failure #" + i);
+            }
+        }
+
+        [Test]
+        public void TestEd448Vector1()
+        {
+            CheckEd448Vector(
+                ( "6c82a562cb808d10d632be89c8513ebf"
+                + "6c929f34ddfa8c9f63c9960ef6e348a3"
+                + "528c8a3fcc2f044e39a3fc5b94492f8f"
+                + "032e7549a20098f95b"),
+                ( "5fd7449b59b461fd2ce787ec616ad46a"
+                + "1da1342485a70e1f8a0ea75d80e96778"
+                + "edf124769b46c7061bd6783df1e50f6c"
+                + "d1fa1abeafe8256180"),
+                "",
+                "",
+                ( "533a37f6bbe457251f023c0d88f976ae"
+                + "2dfb504a843e34d2074fd823d41a591f"
+                + "2b233f034f628281f2fd7a22ddd47d78"
+                + "28c59bd0a21bfd3980ff0d2028d4b18a"
+                + "9df63e006c5d1c2d345b925d8dc00b41"
+                + "04852db99ac5c7cdda8530a113a0f4db"
+                + "b61149f05a7363268c71d95808ff2e65"
+                + "2600"),
+                "Ed448 Vector #1");
+        }
+
+        [Test]
+        public void TestEd448Vector2()
+        {
+            CheckEd448Vector(
+                ( "c4eab05d357007c632f3dbb48489924d"
+                + "552b08fe0c353a0d4a1f00acda2c463a"
+                + "fbea67c5e8d2877c5e3bc397a659949e"
+                + "f8021e954e0a12274e"),
+                ( "43ba28f430cdff456ae531545f7ecd0a"
+                + "c834a55d9358c0372bfa0c6c6798c086"
+                + "6aea01eb00742802b8438ea4cb82169c"
+                + "235160627b4c3a9480"),
+                "03",
+                "",
+                ( "26b8f91727bd62897af15e41eb43c377"
+                + "efb9c610d48f2335cb0bd0087810f435"
+                + "2541b143c4b981b7e18f62de8ccdf633"
+                + "fc1bf037ab7cd779805e0dbcc0aae1cb"
+                + "cee1afb2e027df36bc04dcecbf154336"
+                + "c19f0af7e0a6472905e799f1953d2a0f"
+                + "f3348ab21aa4adafd1d234441cf807c0"
+                + "3a00"),
+                "Ed448 Vector #2");
+        }
+
+        [Test]
+        public void TestEd448Vector3()
+        {
+            CheckEd448Vector(
+                ( "c4eab05d357007c632f3dbb48489924d"
+                + "552b08fe0c353a0d4a1f00acda2c463a"
+                + "fbea67c5e8d2877c5e3bc397a659949e"
+                + "f8021e954e0a12274e"),
+                ( "43ba28f430cdff456ae531545f7ecd0a"
+                + "c834a55d9358c0372bfa0c6c6798c086"
+                + "6aea01eb00742802b8438ea4cb82169c"
+                + "235160627b4c3a9480"),
+                "03",
+                "666f6f",
+                ( "d4f8f6131770dd46f40867d6fd5d5055"
+                + "de43541f8c5e35abbcd001b32a89f7d2"
+                + "151f7647f11d8ca2ae279fb842d60721"
+                + "7fce6e042f6815ea000c85741de5c8da"
+                + "1144a6a1aba7f96de42505d7a7298524"
+                + "fda538fccbbb754f578c1cad10d54d0d"
+                + "5428407e85dcbc98a49155c13764e66c"
+                + "3c00"),
+                "Ed448 Vector #3");
+        }
+
+        [Test]
+        public void TestEd448Vector4()
+        {
+            CheckEd448Vector(
+                ( "cd23d24f714274e744343237b93290f5"
+                + "11f6425f98e64459ff203e8985083ffd"
+                + "f60500553abc0e05cd02184bdb89c4cc"
+                + "d67e187951267eb328"),
+                ( "dcea9e78f35a1bf3499a831b10b86c90"
+                + "aac01cd84b67a0109b55a36e9328b1e3"
+                + "65fce161d71ce7131a543ea4cb5f7e9f"
+                + "1d8b00696447001400"),
+                "0c3e544074ec63b0265e0c",
+                "",
+                ( "1f0a8888ce25e8d458a21130879b840a"
+                + "9089d999aaba039eaf3e3afa090a09d3"
+                + "89dba82c4ff2ae8ac5cdfb7c55e94d5d"
+                + "961a29fe0109941e00b8dbdeea6d3b05"
+                + "1068df7254c0cdc129cbe62db2dc957d"
+                + "bb47b51fd3f213fb8698f064774250a5"
+                + "028961c9bf8ffd973fe5d5c206492b14"
+                + "0e00"),
+                "Ed448 Vector #4");
+        }
+
+        [Test]
+        public void TestEd448Vector5()
+        {
+            CheckEd448Vector(
+                ( "258cdd4ada32ed9c9ff54e63756ae582"
+                + "fb8fab2ac721f2c8e676a72768513d93"
+                + "9f63dddb55609133f29adf86ec9929dc"
+                + "cb52c1c5fd2ff7e21b"),
+                ( "3ba16da0c6f2cc1f30187740756f5e79"
+                + "8d6bc5fc015d7c63cc9510ee3fd44adc"
+                + "24d8e968b6e46e6f94d19b945361726b"
+                + "d75e149ef09817f580"),
+                "64a65f3cdedcdd66811e2915",
+                "",
+                ( "7eeeab7c4e50fb799b418ee5e3197ff6"
+                + "bf15d43a14c34389b59dd1a7b1b85b4a"
+                + "e90438aca634bea45e3a2695f1270f07"
+                + "fdcdf7c62b8efeaf00b45c2c96ba457e"
+                + "b1a8bf075a3db28e5c24f6b923ed4ad7"
+                + "47c3c9e03c7079efb87cb110d3a99861"
+                + "e72003cbae6d6b8b827e4e6c143064ff"
+                + "3c00"),
+                "Ed448 Vector #5");
+        }
+
+        [Test]
+        public void TestEd448Vector6()
+        {
+            CheckEd448Vector(
+                ( "7ef4e84544236752fbb56b8f31a23a10"
+                + "e42814f5f55ca037cdcc11c64c9a3b29"
+                + "49c1bb60700314611732a6c2fea98eeb"
+                + "c0266a11a93970100e"),
+                ( "b3da079b0aa493a5772029f0467baebe"
+                + "e5a8112d9d3a22532361da294f7bb381"
+                + "5c5dc59e176b4d9f381ca0938e13c6c0"
+                + "7b174be65dfa578e80"),
+                "64a65f3cdedcdd66811e2915e7",
+                "",
+                ( "6a12066f55331b6c22acd5d5bfc5d712"
+                + "28fbda80ae8dec26bdd306743c5027cb"
+                + "4890810c162c027468675ecf645a8317"
+                + "6c0d7323a2ccde2d80efe5a1268e8aca"
+                + "1d6fbc194d3f77c44986eb4ab4177919"
+                + "ad8bec33eb47bbb5fc6e28196fd1caf5"
+                + "6b4e7e0ba5519234d047155ac727a105"
+                + "3100"),
+                "Ed448 Vector #6");
+        }
+
+        [Test]
+        public void TestEd448Vector64()
+        {
+            string m =
+                "bd0f6a3747cd561bdddf4640a332461a" +
+                "4a30a12a434cd0bf40d766d9c6d458e5" +
+                "512204a30c17d1f50b5079631f64eb31" +
+                "12182da3005835461113718d1a5ef944";
+
+            CheckEd448Vector(
+                ( "d65df341ad13e008567688baedda8e9d"
+                + "cdc17dc024974ea5b4227b6530e339bf"
+                + "f21f99e68ca6968f3cca6dfe0fb9f4fa"
+                + "b4fa135d5542ea3f01"),
+                ( "df9705f58edbab802c7f8363cfe5560a"
+                + "b1c6132c20a9f1dd163483a26f8ac53a"
+                + "39d6808bf4a1dfbd261b099bb03b3fb5"
+                + "0906cb28bd8a081f00"),
+                m,
+                "",
+                ( "554bc2480860b49eab8532d2a533b7d5"
+                + "78ef473eeb58c98bb2d0e1ce488a98b1"
+                + "8dfde9b9b90775e67f47d4a1c3482058"
+                + "efc9f40d2ca033a0801b63d45b3b722e"
+                + "f552bad3b4ccb667da350192b61c508c"
+                + "f7b6b5adadc2c8d9a446ef003fb05cba"
+                + "5f30e88e36ec2703b349ca229c267083"
+                + "3900"),
+                "Ed448 Vector #64");
+        }
+
+        [Test]
+        public void TestEd448Vector256()
+        {
+            string m =
+                "15777532b0bdd0d1389f636c5f6b9ba7" +
+                "34c90af572877e2d272dd078aa1e567c" +
+                "fa80e12928bb542330e8409f31745041" +
+                "07ecd5efac61ae7504dabe2a602ede89" +
+                "e5cca6257a7c77e27a702b3ae39fc769" +
+                "fc54f2395ae6a1178cab4738e543072f" +
+                "c1c177fe71e92e25bf03e4ecb72f47b6" +
+                "4d0465aaea4c7fad372536c8ba516a60" +
+                "39c3c2a39f0e4d832be432dfa9a706a6" +
+                "e5c7e19f397964ca4258002f7c0541b5" +
+                "90316dbc5622b6b2a6fe7a4abffd9610" +
+                "5eca76ea7b98816af0748c10df048ce0" +
+                "12d901015a51f189f3888145c03650aa" +
+                "23ce894c3bd889e030d565071c59f409" +
+                "a9981b51878fd6fc110624dcbcde0bf7" +
+                "a69ccce38fabdf86f3bef6044819de11";
+
+            CheckEd448Vector(
+                ( "2ec5fe3c17045abdb136a5e6a913e32a"
+                + "b75ae68b53d2fc149b77e504132d3756"
+                + "9b7e766ba74a19bd6162343a21c8590a"
+                + "a9cebca9014c636df5"),
+                ( "79756f014dcfe2079f5dd9e718be4171"
+                + "e2ef2486a08f25186f6bff43a9936b9b"
+                + "fe12402b08ae65798a3d81e22e9ec80e"
+                + "7690862ef3d4ed3a00"),
+                m,
+                "",
+                ( "c650ddbb0601c19ca11439e1640dd931"
+                + "f43c518ea5bea70d3dcde5f4191fe53f"
+                + "00cf966546b72bcc7d58be2b9badef28"
+                + "743954e3a44a23f880e8d4f1cfce2d7a"
+                + "61452d26da05896f0a50da66a239a8a1"
+                + "88b6d825b3305ad77b73fbac0836ecc6"
+                + "0987fd08527c1a8e80d5823e65cafe2a"
+                + "3d00"),
+                "Ed448 Vector #256");
+        }
+
+        [Test]
+        public void TestEd448Vector1023()
+        {
+            string m =
+                "6ddf802e1aae4986935f7f981ba3f035" +
+                "1d6273c0a0c22c9c0e8339168e675412" +
+                "a3debfaf435ed651558007db4384b650" +
+                "fcc07e3b586a27a4f7a00ac8a6fec2cd" +
+                "86ae4bf1570c41e6a40c931db27b2faa" +
+                "15a8cedd52cff7362c4e6e23daec0fbc" +
+                "3a79b6806e316efcc7b68119bf46bc76" +
+                "a26067a53f296dafdbdc11c77f7777e9" +
+                "72660cf4b6a9b369a6665f02e0cc9b6e" +
+                "dfad136b4fabe723d2813db3136cfde9" +
+                "b6d044322fee2947952e031b73ab5c60" +
+                "3349b307bdc27bc6cb8b8bbd7bd32321" +
+                "9b8033a581b59eadebb09b3c4f3d2277" +
+                "d4f0343624acc817804728b25ab79717" +
+                "2b4c5c21a22f9c7839d64300232eb66e" +
+                "53f31c723fa37fe387c7d3e50bdf9813" +
+                "a30e5bb12cf4cd930c40cfb4e1fc6225" +
+                "92a49588794494d56d24ea4b40c89fc0" +
+                "596cc9ebb961c8cb10adde976a5d602b" +
+                "1c3f85b9b9a001ed3c6a4d3b1437f520" +
+                "96cd1956d042a597d561a596ecd3d173" +
+                "5a8d570ea0ec27225a2c4aaff26306d1" +
+                "526c1af3ca6d9cf5a2c98f47e1c46db9" +
+                "a33234cfd4d81f2c98538a09ebe76998" +
+                "d0d8fd25997c7d255c6d66ece6fa56f1" +
+                "1144950f027795e653008f4bd7ca2dee" +
+                "85d8e90f3dc315130ce2a00375a318c7" +
+                "c3d97be2c8ce5b6db41a6254ff264fa6" +
+                "155baee3b0773c0f497c573f19bb4f42" +
+                "40281f0b1f4f7be857a4e59d416c06b4" +
+                "c50fa09e1810ddc6b1467baeac5a3668" +
+                "d11b6ecaa901440016f389f80acc4db9" +
+                "77025e7f5924388c7e340a732e554440" +
+                "e76570f8dd71b7d640b3450d1fd5f041" +
+                "0a18f9a3494f707c717b79b4bf75c984" +
+                "00b096b21653b5d217cf3565c9597456" +
+                "f70703497a078763829bc01bb1cbc8fa" +
+                "04eadc9a6e3f6699587a9e75c94e5bab" +
+                "0036e0b2e711392cff0047d0d6b05bd2" +
+                "a588bc109718954259f1d86678a579a3" +
+                "120f19cfb2963f177aeb70f2d4844826" +
+                "262e51b80271272068ef5b3856fa8535" +
+                "aa2a88b2d41f2a0e2fda7624c2850272" +
+                "ac4a2f561f8f2f7a318bfd5caf969614" +
+                "9e4ac824ad3460538fdc25421beec2cc" +
+                "6818162d06bbed0c40a387192349db67" +
+                "a118bada6cd5ab0140ee273204f628aa" +
+                "d1c135f770279a651e24d8c14d75a605" +
+                "9d76b96a6fd857def5e0b354b27ab937" +
+                "a5815d16b5fae407ff18222c6d1ed263" +
+                "be68c95f32d908bd895cd76207ae7264" +
+                "87567f9a67dad79abec316f683b17f2d" +
+                "02bf07e0ac8b5bc6162cf94697b3c27c" +
+                "d1fea49b27f23ba2901871962506520c" +
+                "392da8b6ad0d99f7013fbc06c2c17a56" +
+                "9500c8a7696481c1cd33e9b14e40b82e" +
+                "79a5f5db82571ba97bae3ad3e0479515" +
+                "bb0e2b0f3bfcd1fd33034efc6245eddd" +
+                "7ee2086ddae2600d8ca73e214e8c2b0b" +
+                "db2b047c6a464a562ed77b73d2d841c4" +
+                "b34973551257713b753632efba348169" +
+                "abc90a68f42611a40126d7cb21b58695" +
+                "568186f7e569d2ff0f9e745d0487dd2e" +
+                "b997cafc5abf9dd102e62ff66cba87";
+
+            CheckEd448Vector(
+                ( "872d093780f5d3730df7c212664b37b8"
+                + "a0f24f56810daa8382cd4fa3f77634ec"
+                + "44dc54f1c2ed9bea86fafb7632d8be19"
+                + "9ea165f5ad55dd9ce8"),
+                ( "a81b2e8a70a5ac94ffdbcc9badfc3feb"
+                + "0801f258578bb114ad44ece1ec0e799d"
+                + "a08effb81c5d685c0c56f64eecaef8cd"
+                + "f11cc38737838cf400"),
+                m,
+                "",
+                ( "e301345a41a39a4d72fff8df69c98075"
+                + "a0cc082b802fc9b2b6bc503f926b65bd"
+                + "df7f4c8f1cb49f6396afc8a70abe6d8a"
+                + "ef0db478d4c6b2970076c6a0484fe76d"
+                + "76b3a97625d79f1ce240e7c576750d29"
+                + "5528286f719b413de9ada3e8eb78ed57"
+                + "3603ce30d8bb761785dc30dbc320869e"
+                + "1a00"),
+                "Ed448 Vector #1023");
+        }
+
+        private static void CheckEd448Vector(string sSK, string sPK, string sM, string sCTX, string sSig, string text)
+        {
+            byte[] sk = Hex.Decode(sSK);
+
+            byte[] pk = Hex.Decode(sPK);
+            byte[] pkGen = new byte[Ed448.PublicKeySize];
+            Ed448.GeneratePublicKey(sk, 0, pkGen, 0);
+            Assert.IsTrue(Arrays.AreEqual(pk, pkGen), text);
+
+            byte[] m = Hex.Decode(sM);
+            byte[] ctx = Hex.Decode(sCTX);
+            byte[] sig = Hex.Decode(sSig);
+            byte[] sigGen = new byte[Ed448.SignatureSize];
+            Ed448.Sign(sk, 0, ctx, m, 0, m.Length, sigGen, 0);
+            Assert.IsTrue(Arrays.AreEqual(sig, sigGen), text);
+
+            Ed448.Sign(sk, 0, pk, 0, ctx, m, 0, m.Length, sigGen, 0);
+            Assert.IsTrue(Arrays.AreEqual(sig, sigGen), text);
+
+            bool shouldVerify = Ed448.Verify(sig, 0, pk, 0, ctx, m, 0, m.Length);
+            Assert.IsTrue(shouldVerify, text);
+
+            sig[Ed448.SignatureSize - 1] ^= 0x80;
+            bool shouldNotVerify = Ed448.Verify(sig, 0, pk, 0, ctx, m, 0, m.Length);
+            Assert.IsFalse(shouldNotVerify, text);
+        }
+    }
+}