summary refs log tree commit diff
path: root/crypto/src/math/ec/custom/sec/Nat512.cs
blob: 46e10f99551efde9b25bc5c0be16b22a26ba9c09 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
using System;
using System.Diagnostics;

namespace Org.BouncyCastle.Math.EC.Custom.Sec
{
    internal abstract class Nat512
    {
        public static void Mul(uint[] x, uint[] y, uint[] zz)
        {
            Nat256.Mul(x, y, zz);
            Nat256.Mul(x, 8, y, 8, zz, 16);

            uint c24 = Nat256.AddToEachOther(zz, 8, zz, 16);
            uint c16 = c24 + Nat256.AddTo(zz, 0, zz, 8, 0);
            c24 += Nat256.AddTo(zz, 24, zz, 16, c16);

            uint[] dx = Nat256.Create(), dy = Nat256.Create();
            bool neg = Nat256.Diff(x, 8, x, 0, dx, 0) != Nat256.Diff(y, 8, y, 0, dy, 0);

            uint[] tt = Nat256.CreateExt();
            Nat256.Mul(dx, dy, tt);

            c24 += neg ? Nat.AddTo(16, tt, 0, zz, 8) : (uint)Nat.SubFrom(16, tt, 0, zz, 8);
            Nat.AddWordAt(32, c24, zz, 24); 
        }

        public static void Square(uint[] x, uint[] zz)
        {
            Nat256.Square(x, zz);
            Nat256.Square(x, 8, zz, 16);

            uint c24 = Nat256.AddToEachOther(zz, 8, zz, 16);
            uint c16 = c24 + Nat256.AddTo(zz, 0, zz, 8, 0);
            c24 += Nat256.AddTo(zz, 24, zz, 16, c16);

            uint[] dx = Nat256.Create();
            Nat256.Diff(x, 8, x, 0, dx, 0);

            uint[] m = Nat256.CreateExt();
            Nat256.Square(dx, m);

            c24 += (uint)Nat.SubFrom(16, m, 0, zz, 8);
            Nat.AddWordAt(32, c24, zz, 24); 
        }
    }
}