Add custom curve for secp384r1 (P-384)

1 files changed, 46 insertions, 0 deletions

diff --git a/crypto/src/math/ec/custom/sec/Nat384.cs b/crypto/src/math/ec/custom/sec/Nat384.cs
new file mode 100644
index 000000000..273ee2d65
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/Nat384.cs
@@ -0,0 +1,46 @@
+using System;
+using System.Diagnostics;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal abstract class Nat384
+    {
+        public static void Mul(uint[] x, uint[] y, uint[] zz)
+        {
+            Nat192.Mul(x, y, zz);
+            Nat192.Mul(x, 6, y, 6, zz, 12);
+
+            uint c18 = Nat192.AddToEachOther(zz, 6, zz, 12);
+            uint c12 = c18 + Nat192.AddTo(zz, 0, zz, 6, 0);
+            c18 += Nat192.AddTo(zz, 18, zz, 12, c12);
+
+            uint[] dx = Nat192.Create(), dy = Nat192.Create();
+            bool neg = Nat192.Diff(x, 6, x, 0, dx, 0) != Nat192.Diff(y, 6, y, 0, dy, 0);
+
+            uint[] tt = Nat192.CreateExt();
+            Nat192.Mul(dx, dy, tt);
+
+            c18 += neg ? Nat.AddTo(12, tt, 0, zz, 6) : (uint)Nat.SubFrom(12, tt, 0, zz, 6);
+            Nat.AddWordExt(12, c18, zz, 18);
+        }
+
+        public static void Square(uint[] x, uint[] zz)
+        {
+            Nat192.Square(x, zz);
+            Nat192.Square(x, 6, zz, 12);
+
+            uint c18 = Nat192.AddToEachOther(zz, 6, zz, 12);
+            uint c12 = c18 + Nat192.AddTo(zz, 0, zz, 6, 0);
+            c18 += Nat192.AddTo(zz, 18, zz, 12, c12);
+
+            uint[] dx = Nat192.Create();
+            Nat192.Diff(x, 6, x, 0, dx, 0);
+
+            uint[] m = Nat192.CreateExt();
+            Nat192.Square(dx, m);
+
+            c18 += (uint)Nat.SubFrom(12, m, 0, zz, 6);
+            Nat.AddWordExt(12, c18, zz, 18);
+        }
+    }
+}