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9.5 KiB

#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