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authorPeter Dettman <peter.dettman@bouncycastle.org>2014-03-06 10:54:16 +0700
committerPeter Dettman <peter.dettman@bouncycastle.org>2014-03-06 10:54:16 +0700
commit974c5178fc0b4ffbdd0aed7c3c24d646b0e1af74 (patch)
tree3af64e57a23bd5845102be9b43edbc7ab6f17f8d
parentAvoid redundant subtraction (diff)
downloadBouncyCastle.NET-ed25519-974c5178fc0b4ffbdd0aed7c3c24d646b0e1af74.tar.xz
Minor improvement to reduction release-1.8.0-beta.2
-rw-r--r--crypto/src/math/ec/custom/sec/SecP224R1Field.cs6
-rw-r--r--crypto/src/math/ec/custom/sec/SecP256R1Field.cs8
-rw-r--r--crypto/src/math/ec/custom/sec/SecP384R1Field.cs10
3 files changed, 15 insertions, 9 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecP224R1Field.cs b/crypto/src/math/ec/custom/sec/SecP224R1Field.cs
index 712d6a46d..3f9f79fc3 100644
--- a/crypto/src/math/ec/custom/sec/SecP224R1Field.cs
+++ b/crypto/src/math/ec/custom/sec/SecP224R1Field.cs
@@ -97,8 +97,10 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
 
             const long n = 1;
 
+            t0 -= n;
+
             long cc = 0;
-            cc += (long)xx[0] - t0 + n;
+            cc += (long)xx[0] - t0;
             z[0] = (uint)cc;
             cc >>= 32;
             cc += (long)xx[1] - t1;
@@ -107,7 +109,7 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
             cc += (long)xx[2] - t2;
             z[2] = (uint)cc;
             cc >>= 32;
-            cc += (long)xx[3] + t0 - xx10 - n;
+            cc += (long)xx[3] + t0 - xx10;
             z[3] = (uint)cc;
             cc >>= 32;
             cc += (long)xx[4] + t1 - xx11;
diff --git a/crypto/src/math/ec/custom/sec/SecP256R1Field.cs b/crypto/src/math/ec/custom/sec/SecP256R1Field.cs
index cc2fe4866..aeb6f52fc 100644
--- a/crypto/src/math/ec/custom/sec/SecP256R1Field.cs
+++ b/crypto/src/math/ec/custom/sec/SecP256R1Field.cs
@@ -98,8 +98,10 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
 
             const long n = 6;
 
+            t0 -= n;
+
             long cc = 0;
-            cc += (long)xx[0] + t0 - t3 - t5 - n;
+            cc += (long)xx[0] + t0 - t3 - t5;
             z[0] = (uint)cc;
             cc >>= 32;
             cc += (long)xx[1] + t1 - t4 - t6;
@@ -108,7 +110,7 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
             cc += (long)xx[2] + t2 - t5 - xx15;
             z[2] = (uint)cc;
             cc >>= 32;
-            cc += (long)xx[3] + (t3 << 1) + xx13 - xx15 - t0 + n;
+            cc += (long)xx[3] + (t3 << 1) + xx13 - xx15 - t0;
             z[3] = (uint)cc;
             cc >>= 32;
             cc += (long)xx[4] + (t4 << 1) + xx14 - t1;
@@ -117,7 +119,7 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
             cc += (long)xx[5] + (t5 << 1) + xx15 - t2;
             z[5] = (uint)cc;
             cc >>= 32;
-            cc += (long)xx[6] + (t6 << 1) + t5 - t0 + n;
+            cc += (long)xx[6] + (t6 << 1) + t5 - t0;
             z[6] = (uint)cc;
             cc >>= 32;
             cc += (long)xx[7] + (xx15 << 1) + xx15 + xx08 - t2 - t4 - n;
diff --git a/crypto/src/math/ec/custom/sec/SecP384R1Field.cs b/crypto/src/math/ec/custom/sec/SecP384R1Field.cs
index dc531f4de..a12529d2c 100644
--- a/crypto/src/math/ec/custom/sec/SecP384R1Field.cs
+++ b/crypto/src/math/ec/custom/sec/SecP384R1Field.cs
@@ -97,20 +97,22 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
 
             const long n = 1;
 
+            xx12 -= n;
+
             long cc = 0;
-            cc += (long)xx[0] + xx12 + xx20 + xx21 - xx23 - n;
+            cc += (long)xx[0] + xx12 + xx20 + xx21 - xx23;
             z[0] = (uint)cc;
             cc >>= 32;
-            cc += (long)xx[1] + xx13 + xx22 + xx23 - xx12 - xx20 + n;
+            cc += (long)xx[1] + xx13 + xx22 + xx23 - xx12 - xx20;
             z[1] = (uint)cc;
             cc >>= 32;
             cc += (long)xx[2] + xx14 + xx23 - xx13 - xx21;
             z[2] = (uint)cc;
             cc >>= 32;
-            cc += (long)xx[3] + xx12 + xx15 + xx20 + xx21 - xx14 - xx22 - xx23 - n;
+            cc += (long)xx[3] + xx12 + xx15 + xx20 + xx21 - xx14 - xx22 - xx23;
             z[3] = (uint)cc;
             cc >>= 32;
-            cc += (long)xx[4] + xx12 + xx13 + xx16 + xx20 + ((xx21 - xx23) << 1) + xx22 - xx15 - n;
+            cc += (long)xx[4] + xx12 + xx13 + xx16 + xx20 + ((xx21 - xx23) << 1) + xx22 - xx15;
             z[4] = (uint)cc;
             cc >>= 32;
             cc += (long)xx[5] + xx13 + xx14 + xx17 + xx21 + (xx22 << 1) + xx23 - xx16;