315 lines
8.2 KiB
C#
315 lines
8.2 KiB
C#
using System;
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namespace Org.BouncyCastle.Crypto.Digests
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{
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/**
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* Draft FIPS 180-2 implementation of SHA-256. <b>Note:</b> As this is
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* based on a draft this implementation is subject to change.
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*
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* <pre>
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* block word digest
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* SHA-1 512 32 160
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* SHA-256 512 32 256
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* SHA-384 1024 64 384
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* SHA-512 1024 64 512
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* </pre>
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*/
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public class Sha256Digest
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: GeneralDigest
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{
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private const int DigestLength = 32;
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private uint H1, H2, H3, H4, H5, H6, H7, H8;
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private uint[] X = new uint[64];
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private int xOff;
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public Sha256Digest()
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{
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initHs();
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}
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/**
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* Copy constructor. This will copy the state of the provided
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* message digest.
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*/
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public Sha256Digest(Sha256Digest t) : base(t)
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{
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H1 = t.H1;
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H2 = t.H2;
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H3 = t.H3;
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H4 = t.H4;
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H5 = t.H5;
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H6 = t.H6;
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H7 = t.H7;
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H8 = t.H8;
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Array.Copy(t.X, 0, X, 0, t.X.Length);
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xOff = t.xOff;
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}
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public override string AlgorithmName
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{
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get { return "SHA-256"; }
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}
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public override int GetDigestSize()
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{
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return DigestLength;
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}
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internal override void ProcessWord(
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byte[] input,
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int inOff)
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{
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X[xOff++] = (((uint)input[inOff]) << 24)
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| (((uint)input[inOff + 1]) << 16)
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| (((uint)input[inOff + 2]) << 8)
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| ((uint)input[inOff + 3]);
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if (xOff == 16)
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{
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ProcessBlock();
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}
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}
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private void UnpackWord(
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uint word,
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byte[] outBytes,
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int outOff)
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{
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outBytes[outOff] = (byte)(word >> 24);
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outBytes[outOff + 1] = (byte)(word >> 16);
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outBytes[outOff + 2] = (byte)(word >> 8);
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outBytes[outOff + 3] = (byte)word;
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}
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internal override void ProcessLength(
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long bitLength)
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{
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if (xOff > 14)
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{
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ProcessBlock();
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}
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X[14] = (uint)((ulong)bitLength >> 32);
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X[15] = (uint)((ulong)bitLength);
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}
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public override int DoFinal(
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byte[] output,
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int outOff)
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{
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Finish();
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UnpackWord(H1, output, outOff);
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UnpackWord(H2, output, outOff + 4);
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UnpackWord(H3, output, outOff + 8);
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UnpackWord(H4, output, outOff + 12);
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UnpackWord(H5, output, outOff + 16);
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UnpackWord(H6, output, outOff + 20);
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UnpackWord(H7, output, outOff + 24);
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UnpackWord(H8, output, outOff + 28);
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Reset();
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return DigestLength;
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}
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/**
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* reset the chaining variables
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*/
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public override void Reset()
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{
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base.Reset();
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initHs();
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xOff = 0;
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Array.Clear(X, 0, X.Length);
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}
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private void initHs()
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{
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/* SHA-256 initial hash value
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* The first 32 bits of the fractional parts of the square roots
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* of the first eight prime numbers
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*/
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H1 = 0x6a09e667;
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H2 = 0xbb67ae85;
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H3 = 0x3c6ef372;
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H4 = 0xa54ff53a;
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H5 = 0x510e527f;
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H6 = 0x9b05688c;
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H7 = 0x1f83d9ab;
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H8 = 0x5be0cd19;
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}
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internal override void ProcessBlock()
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{
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//
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// expand 16 word block into 64 word blocks.
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//
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for (int ti = 16; ti <= 63; ti++)
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{
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X[ti] = Theta1(X[ti - 2]) + X[ti - 7] + Theta0(X[ti - 15]) + X[ti - 16];
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}
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//
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// set up working variables.
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//
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uint a = H1;
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uint b = H2;
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uint c = H3;
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uint d = H4;
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uint e = H5;
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uint f = H6;
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uint g = H7;
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uint h = H8;
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int t = 0;
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for(int i = 0; i < 8; ++i)
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{
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// t = 8 * i
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h += Sum1Ch(e, f, g) + K[t] + X[t++];
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d += h;
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h += Sum0Maj(a, b, c);
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// t = 8 * i + 1
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g += Sum1Ch(d, e, f) + K[t] + X[t++];
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c += g;
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g += Sum0Maj(h, a, b);
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// t = 8 * i + 2
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f += Sum1Ch(c, d, e) + K[t] + X[t++];
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b += f;
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f += Sum0Maj(g, h, a);
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// t = 8 * i + 3
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e += Sum1Ch(b, c, d) + K[t] + X[t++];
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a += e;
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e += Sum0Maj(f, g, h);
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// t = 8 * i + 4
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d += Sum1Ch(a, b, c) + K[t] + X[t++];
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h += d;
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d += Sum0Maj(e, f, g);
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// t = 8 * i + 5
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c += Sum1Ch(h, a, b) + K[t] + X[t++];
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g += c;
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c += Sum0Maj(d, e, f);
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// t = 8 * i + 6
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b += Sum1Ch(g, h, a) + K[t] + X[t++];
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f += b;
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b += Sum0Maj(c, d, e);
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// t = 8 * i + 7
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a += Sum1Ch(f, g, h) + K[t] + X[t++];
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e += a;
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a += Sum0Maj(b, c, d);
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}
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H1 += a;
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H2 += b;
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H3 += c;
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H4 += d;
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H5 += e;
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H6 += f;
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H7 += g;
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H8 += h;
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//
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// reset the offset and clean out the word buffer.
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//
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xOff = 0;
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Array.Clear(X, 0, 16);
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}
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private static uint Sum1Ch(
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uint x,
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uint y,
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uint z)
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{
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// return Sum1(x) + Ch(x, y, z);
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return (((x >> 6) | (x << 26)) ^ ((x >> 11) | (x << 21)) ^ ((x >> 25) | (x << 7)))
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+ ((x & y) ^ ((~x) & z));
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}
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private static uint Sum0Maj(
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uint x,
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uint y,
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uint z)
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{
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// return Sum0(x) + Maj(x, y, z);
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return (((x >> 2) | (x << 30)) ^ ((x >> 13) | (x << 19)) ^ ((x >> 22) | (x << 10)))
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+ ((x & y) ^ (x & z) ^ (y & z));
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}
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// /* SHA-256 functions */
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// private static uint Ch(
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// uint x,
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// uint y,
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// uint z)
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// {
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// return ((x & y) ^ ((~x) & z));
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// }
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//
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// private static uint Maj(
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// uint x,
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// uint y,
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// uint z)
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// {
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// return ((x & y) ^ (x & z) ^ (y & z));
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// }
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//
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// private static uint Sum0(
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// uint x)
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// {
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// return ((x >> 2) | (x << 30)) ^ ((x >> 13) | (x << 19)) ^ ((x >> 22) | (x << 10));
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// }
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//
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// private static uint Sum1(
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// uint x)
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// {
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// return ((x >> 6) | (x << 26)) ^ ((x >> 11) | (x << 21)) ^ ((x >> 25) | (x << 7));
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// }
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private static uint Theta0(
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uint x)
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{
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return ((x >> 7) | (x << 25)) ^ ((x >> 18) | (x << 14)) ^ (x >> 3);
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}
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private static uint Theta1(
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uint x)
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{
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return ((x >> 17) | (x << 15)) ^ ((x >> 19) | (x << 13)) ^ (x >> 10);
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}
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/* SHA-256 Constants
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* (represent the first 32 bits of the fractional parts of the
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* cube roots of the first sixty-four prime numbers)
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*/
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private static readonly uint[] K = {
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0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
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0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
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0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
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0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
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0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
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0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
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0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
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0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
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0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
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0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
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0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
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0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
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0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
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0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
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0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
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0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
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};
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}
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}
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