diff --git a/crypto/src/math/ec/custom/sec/SecT571Field.cs b/crypto/src/math/ec/custom/sec/SecT571Field.cs
index fc84e336b..98f4f7fc2 100644
--- a/crypto/src/math/ec/custom/sec/SecT571Field.cs
+++ b/crypto/src/math/ec/custom/sec/SecT571Field.cs
@@ -11,6 +11,9 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
private const ulong RM = 0xEF7BDEF7BDEF7BDEUL;
+ private static readonly ulong[] ROOT_Z = new ulong[]{ 0x2BE1195F08CAFB99UL, 0x95F08CAF84657C23UL, 0xCAF84657C232BE11UL, 0x657C232BE1195F08UL,
+ 0xF84657C2308CAF84UL, 0x7C232BE1195F08CAUL, 0xBE1195F08CAF8465UL, 0x5F08CAF84657C232UL, 0x784657C232BE119UL };
+
public static void Add(ulong[] x, ulong[] y, ulong[] z)
{
for (int i = 0; i < 9; ++i)
@@ -156,6 +159,28 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
z[zOff + 8] = z8 & M59;
}
+ public static void Sqrt(ulong[] x, ulong[] z)
+ {
+ ulong[] evn = Nat576.Create64(), odd = Nat576.Create64();
+
+ int pos = 0;
+ for (int i = 0; i < 4; ++i)
+ {
+ ulong u0 = Interleave.Unshuffle(x[pos++]);
+ ulong u1 = Interleave.Unshuffle(x[pos++]);
+ evn[i] = (u0 & 0x00000000FFFFFFFFUL) | (u1 << 32);
+ odd[i] = (u0 >> 32) | (u1 & 0xFFFFFFFF00000000UL);
+ }
+ {
+ ulong u0 = Interleave.Unshuffle(x[pos]);
+ evn[4] = (u0 & 0x00000000FFFFFFFFUL);
+ odd[4] = (u0 >> 32);
+ }
+
+ Multiply(odd, ROOT_Z, z);
+ Add(z, evn, z);
+ }
+
public static void Square(ulong[] x, ulong[] z)
{
ulong[] tt = Nat576.CreateExt64();
@@ -185,6 +210,12 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
}
}
+ public static uint Trace(ulong[] x)
+ {
+ // Non-zero-trace bits: 0, 561, 569
+ return (uint)(x[0] ^ (x[8] >> 49) ^ (x[8] >> 57)) & 1U;
+ }
+
protected static void ImplMultiply(ulong[] x, ulong[] y, ulong[] zz)
{
//for (int i = 0; i < 9; ++i)
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