diff --git a/crypto/src/math/ec/custom/sec/SecT163Field.cs b/crypto/src/math/ec/custom/sec/SecT163Field.cs
index f921a5bc7..b1e9aa725 100644
--- a/crypto/src/math/ec/custom/sec/SecT163Field.cs
+++ b/crypto/src/math/ec/custom/sec/SecT163Field.cs
@@ -10,6 +10,8 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
private const ulong M35 = ulong.MaxValue >> 29;
private const ulong M55 = ulong.MaxValue >> 9;
+ private static readonly ulong[] ROOT_Z = new ulong[]{ 0xB6DB6DB6DB6DB6B0UL, 0x492492492492DB6DUL, 0x492492492UL };
+
public static void Add(ulong[] x, ulong[] y, ulong[] z)
{
z[0] = x[0] ^ y[0];
@@ -122,6 +124,25 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
z[zOff + 2] = z2 & M35;
}
+ public static void Sqrt(ulong[] x, ulong[] z)
+ {
+ ulong[] odd = Nat192.Create64();
+
+ ulong u0, u1;
+ u0 = Interleave.Unshuffle(x[0]); u1 = Interleave.Unshuffle(x[1]);
+ ulong e0 = (u0 & 0x00000000FFFFFFFFUL) | (u1 << 32);
+ odd[0] = (u0 >> 32) | (u1 & 0xFFFFFFFF00000000UL);
+
+ u0 = Interleave.Unshuffle(x[2]);
+ ulong e1 = (u0 & 0x00000000FFFFFFFFUL);
+ odd[1] = (u0 >> 32);
+
+ Multiply(odd, ROOT_Z, z);
+
+ z[0] ^= e0;
+ z[1] ^= e1;
+ }
+
public static void Square(ulong[] x, ulong[] z)
{
ulong[] tt = Nat192.CreateExt64();
@@ -151,6 +172,12 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec
}
}
+ public static uint Trace(ulong[] x)
+ {
+ // Non-zero-trace bits: 0, 157
+ return (uint)(x[0] ^ (x[2] >> 29)) & 1U;
+ }
+
protected static void ImplCompactExt(ulong[] zz)
{
ulong z0 = zz[0], z1 = zz[1], z2 = zz[2], z3 = zz[3], z4 = zz[4], z5 = zz[5];
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