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#if NET20
using System;using System.Security;using System.Security.Cryptography;
namespace Apewer.Internals{
internal class SHA256CryptoServiceProvider : HashAlgorithm {
private byte[] _buffer;
private long _count;
private uint[] _stateSHA256;
private uint[] _W;
private static readonly uint[] _K = new uint[64] { 1116352408u, 1899447441u, 3049323471u, 3921009573u, 961987163u, 1508970993u, 2453635748u, 2870763221u, 3624381080u, 310598401u, 607225278u, 1426881987u, 1925078388u, 2162078206u, 2614888103u, 3248222580u, 3835390401u, 4022224774u, 264347078u, 604807628u, 770255983u, 1249150122u, 1555081692u, 1996064986u, 2554220882u, 2821834349u, 2952996808u, 3210313671u, 3336571891u, 3584528711u, 113926993u, 338241895u, 666307205u, 773529912u, 1294757372u, 1396182291u, 1695183700u, 1986661051u, 2177026350u, 2456956037u, 2730485921u, 2820302411u, 3259730800u, 3345764771u, 3516065817u, 3600352804u, 4094571909u, 275423344u, 430227734u, 506948616u, 659060556u, 883997877u, 958139571u, 1322822218u, 1537002063u, 1747873779u, 1955562222u, 2024104815u, 2227730452u, 2361852424u, 2428436474u, 2756734187u, 3204031479u, 3329325298u };
public SHA256CryptoServiceProvider() { HashSizeValue = 256; _stateSHA256 = new uint[8]; _buffer = new byte[64]; _W = new uint[64]; InitializeState(); }
public override void Initialize() { InitializeState(); Array.Clear(_buffer, 0, _buffer.Length); Array.Clear(_W, 0, _W.Length); }
protected override void HashCore(byte[] rgb, int ibStart, int cbSize) { _HashData(rgb, ibStart, cbSize); }
protected override byte[] HashFinal() { return _EndHash(); }
private void InitializeState() { _count = 0L; _stateSHA256[0] = 1779033703u; _stateSHA256[1] = 3144134277u; _stateSHA256[2] = 1013904242u; _stateSHA256[3] = 2773480762u; _stateSHA256[4] = 1359893119u; _stateSHA256[5] = 2600822924u; _stateSHA256[6] = 528734635u; _stateSHA256[7] = 1541459225u; }
[SecuritySafeCritical] private unsafe void _HashData(byte[] partIn, int ibStart, int cbSize) { int num = cbSize; int num2 = ibStart; int num3 = (int)(_count & 0x3F); _count += num; fixed (uint* state = _stateSHA256) { fixed (byte* block = _buffer) { fixed (uint* expandedBuffer = _W) { if (num3 > 0 && num3 + num >= 64) { Array.Copy(partIn, num2, _buffer, num3, 64 - num3); num2 += 64 - num3; num -= 64 - num3; SHATransform(expandedBuffer, state, block); num3 = 0; } while (num >= 64) { Array.Copy(partIn, num2, _buffer, 0, 64); num2 += 64; num -= 64; SHATransform(expandedBuffer, state, block); } if (num > 0) { Array.Copy(partIn, num2, _buffer, num3, num); } } } } }
private byte[] _EndHash() { byte[] array = new byte[32]; int num = 64 - (int)(_count & 0x3F); if (num <= 8) { num += 64; } byte[] array2 = new byte[num]; array2[0] = 128; long num2 = _count * 8; array2[num - 8] = (byte)((num2 >> 56) & 0xFF); array2[num - 7] = (byte)((num2 >> 48) & 0xFF); array2[num - 6] = (byte)((num2 >> 40) & 0xFF); array2[num - 5] = (byte)((num2 >> 32) & 0xFF); array2[num - 4] = (byte)((num2 >> 24) & 0xFF); array2[num - 3] = (byte)((num2 >> 16) & 0xFF); array2[num - 2] = (byte)((num2 >> 8) & 0xFF); array2[num - 1] = (byte)(num2 & 0xFF); _HashData(array2, 0, array2.Length); DWORDToBigEndian(array, _stateSHA256, 8); HashValue = array; return array; }
[SecurityCritical] private unsafe static void SHATransform(uint* expandedBuffer, uint* state, byte* block) { uint num = *state; uint num2 = state[1]; uint num3 = state[2]; uint num4 = state[3]; uint num5 = state[4]; uint num6 = state[5]; uint num7 = state[6]; uint num8 = state[7]; DWORDFromBigEndian(expandedBuffer, 16, block); SHA256Expand(expandedBuffer); int num9; for (num9 = 0; num9 < 64; num9++) { uint num10 = num8 + Sigma_1(num5) + Ch(num5, num6, num7) + _K[num9] + expandedBuffer[num9]; uint num11 = num4 + num10; uint num12 = num10 + Sigma_0(num) + Maj(num, num2, num3); num9++; num10 = num7 + Sigma_1(num11) + Ch(num11, num5, num6) + _K[num9] + expandedBuffer[num9]; uint num13 = num3 + num10; uint num14 = num10 + Sigma_0(num12) + Maj(num12, num, num2); num9++; num10 = num6 + Sigma_1(num13) + Ch(num13, num11, num5) + _K[num9] + expandedBuffer[num9]; uint num15 = num2 + num10; uint num16 = num10 + Sigma_0(num14) + Maj(num14, num12, num); num9++; num10 = num5 + Sigma_1(num15) + Ch(num15, num13, num11) + _K[num9] + expandedBuffer[num9]; uint num17 = num + num10; uint num18 = num10 + Sigma_0(num16) + Maj(num16, num14, num12); num9++; num10 = num11 + Sigma_1(num17) + Ch(num17, num15, num13) + _K[num9] + expandedBuffer[num9]; num8 = num12 + num10; num4 = num10 + Sigma_0(num18) + Maj(num18, num16, num14); num9++; num10 = num13 + Sigma_1(num8) + Ch(num8, num17, num15) + _K[num9] + expandedBuffer[num9]; num7 = num14 + num10; num3 = num10 + Sigma_0(num4) + Maj(num4, num18, num16); num9++; num10 = num15 + Sigma_1(num7) + Ch(num7, num8, num17) + _K[num9] + expandedBuffer[num9]; num6 = num16 + num10; num2 = num10 + Sigma_0(num3) + Maj(num3, num4, num18); num9++; num10 = num17 + Sigma_1(num6) + Ch(num6, num7, num8) + _K[num9] + expandedBuffer[num9]; num5 = num18 + num10; num = num10 + Sigma_0(num2) + Maj(num2, num3, num4); } *state += num; state[1] += num2; state[2] += num3; state[3] += num4; state[4] += num5; state[5] += num6; state[6] += num7; state[7] += num8; }
private static uint RotateRight(uint x, int n) { return (x >> n) | (x << 32 - n); }
private static uint Ch(uint x, uint y, uint z) { return (x & y) ^ (uint)(((int)x ^ -1) & (int)z); }
private static uint Maj(uint x, uint y, uint z) { return (x & y) ^ (x & z) ^ (y & z); }
private static uint sigma_0(uint x) { return RotateRight(x, 7) ^ RotateRight(x, 18) ^ (x >> 3); }
private static uint sigma_1(uint x) { return RotateRight(x, 17) ^ RotateRight(x, 19) ^ (x >> 10); }
private static uint Sigma_0(uint x) { return RotateRight(x, 2) ^ RotateRight(x, 13) ^ RotateRight(x, 22); }
private static uint Sigma_1(uint x) { return RotateRight(x, 6) ^ RotateRight(x, 11) ^ RotateRight(x, 25); }
[SecurityCritical] private unsafe static void SHA256Expand(uint* x) { for (int i = 16; i < 64; i++) { x[i] = sigma_1(x[i - 2]) + x[i - 7] + sigma_0(x[i - 15]) + x[i - 16]; } }
private static void DWORDToBigEndian(byte[] block, uint[] x, int digits) { int num = 0; int num2 = 0; while (num < digits) { block[num2] = (byte)((x[num] >> 24) & 0xFF); block[num2 + 1] = (byte)((x[num] >> 16) & 0xFF); block[num2 + 2] = (byte)((x[num] >> 8) & 0xFF); block[num2 + 3] = (byte)(x[num] & 0xFF); num++; num2 += 4; } }
[SecurityCritical] private unsafe static void DWORDFromBigEndian(uint* x, int digits, byte* block) { int num = 0; int num2 = 0; while (num < digits) { x[num] = (uint)((block[num2] << 24) | (block[num2 + 1] << 16) | (block[num2 + 2] << 8) | block[num2 + 3]); num++; num2 += 4; } }
}
}
#endif
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