//
// System.Security.Cryptography.SHA256Managed.cs
//
// Author:
// Matthew S. Ford (Matthew.S.Ford@Rose-Hulman.Edu)
//
// (C) 2001
// Copyright (C) 2004, 2005 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System.Runtime.InteropServices;
namespace System.Security.Cryptography{
[ComVisible (true)]
public class SHA256Managed : SHA256 {
private const int BLOCK_SIZE_BYTES = 64;
private uint[] _H;
private ulong count;
private byte[] _ProcessingBuffer; // Used to start data when passed less than a block worth.
private int _ProcessingBufferCount; // Counts how much data we have stored that still needs processed.
private uint[] buff;
public SHA256Managed ()
{
_H = new uint [8];
_ProcessingBuffer = new byte [BLOCK_SIZE_BYTES];
buff = new uint[64];
Initialize ();
}
protected override void HashCore (byte[] rgb, int ibStart, int cbSize)
{
int i;
State = 1;
if (_ProcessingBufferCount != 0) {
if (cbSize < (BLOCK_SIZE_BYTES - _ProcessingBufferCount)) {
System.Buffer.BlockCopy (rgb, ibStart, _ProcessingBuffer, _ProcessingBufferCount, cbSize);
_ProcessingBufferCount += cbSize;
return;
}
else {
i = (BLOCK_SIZE_BYTES - _ProcessingBufferCount);
System.Buffer.BlockCopy (rgb, ibStart, _ProcessingBuffer, _ProcessingBufferCount, i);
ProcessBlock (_ProcessingBuffer, 0);
_ProcessingBufferCount = 0;
ibStart += i;
cbSize -= i;
}
}
for (i = 0; i < cbSize - cbSize % BLOCK_SIZE_BYTES; i += BLOCK_SIZE_BYTES) {
ProcessBlock (rgb, ibStart + i);
}
if (cbSize % BLOCK_SIZE_BYTES != 0) {
System.Buffer.BlockCopy (rgb, cbSize - cbSize % BLOCK_SIZE_BYTES + ibStart, _ProcessingBuffer, 0, cbSize % BLOCK_SIZE_BYTES);
_ProcessingBufferCount = cbSize % BLOCK_SIZE_BYTES;
}
}
protected override byte[] HashFinal ()
{
byte[] hash = new byte[32];
int i, j;
ProcessFinalBlock (_ProcessingBuffer, 0, _ProcessingBufferCount);
for (i=0; i<8; i++) {
for (j=0; j<4; j++) {
hash[i*4+j] = (byte)(_H[i] >> (24-j*8));
}
}
State = 0;
return hash;
}
public override void Initialize ()
{
count = 0;
_ProcessingBufferCount = 0;
_H[0] = 0x6A09E667;
_H[1] = 0xBB67AE85;
_H[2] = 0x3C6EF372;
_H[3] = 0xA54FF53A;
_H[4] = 0x510E527F;
_H[5] = 0x9B05688C;
_H[6] = 0x1F83D9AB;
_H[7] = 0x5BE0CD19;
}
private void ProcessBlock (byte[] inputBuffer, int inputOffset)
{
uint a, b, c, d, e, f, g, h;
uint t1, t2;
int i;
uint[] K1 = SHAConstants.K1;
uint[] buff = this.buff;
count += BLOCK_SIZE_BYTES;
for (i=0; i<16; i++) {
buff[i] = (uint)(((inputBuffer[inputOffset + 4 * i]) << 24)
| ((inputBuffer[inputOffset + 4 * i + 1]) << 16)
| ((inputBuffer[inputOffset + 4 * i + 2]) << 8)
| ((inputBuffer[inputOffset + 4 * i + 3])));
}
for (i=16; i<64; i++) {
t1 = buff[i - 15];
t1 = (((t1 >> 7) | (t1 << 25)) ^ ((t1 >> 18) | (t1 << 14)) ^ (t1 >> 3));
t2 = buff[i - 2];
t2 = (((t2 >> 17) | (t2 << 15)) ^ ((t2 >> 19) | (t2 << 13)) ^ (t2 >> 10));
buff[i] = t2 + buff[i - 7] + t1 + buff[i - 16];
}
a = _H[0];
b = _H[1];
c = _H[2];
d = _H[3];
e = _H[4];
f = _H[5];
g = _H[6];
h = _H[7];
for (i=0; i<64; i++) {
t1 = h + (((e >> 6) | (e << 26)) ^ ((e >> 11) | (e << 21)) ^ ((e >> 25) | (e << 7))) + ((e & f) ^ (~e & g)) + K1[i] + buff[i];
t2 = (((a >> 2) | (a << 30)) ^ ((a >> 13) | (a << 19)) ^ ((a >> 22) | (a << 10)));
t2 = t2 + ((a & b) ^ (a & c) ^ (b & c));
h = g;
g = f;
f = e;
e = d + t1;
d = c;
c = b;
b = a;
a = t1 + t2;
}
_H[0] += a;
_H[1] += b;
_H[2] += c;
_H[3] += d;
_H[4] += e;
_H[5] += f;
_H[6] += g;
_H[7] += h;
}
private void ProcessFinalBlock (byte[] inputBuffer, int inputOffset, int inputCount)
{
ulong total = count + (ulong)inputCount;
int paddingSize = (56 - (int)(total % BLOCK_SIZE_BYTES));
if (paddingSize < 1)
paddingSize += BLOCK_SIZE_BYTES;
byte[] fooBuffer = new byte[inputCount+paddingSize+8];
for (int i=0; i<inputCount; i++) {
fooBuffer[i] = inputBuffer[i+inputOffset];
}
fooBuffer[inputCount] = 0x80;
for (int i=inputCount+1; i<inputCount+paddingSize; i++) {
fooBuffer[i] = 0x00;
}
// I deal in bytes. The algorithm deals in bits.
ulong size = total << 3;
AddLength (size, fooBuffer, inputCount+paddingSize);
ProcessBlock (fooBuffer, 0);
if (inputCount+paddingSize+8 == 128) {
ProcessBlock(fooBuffer, 64);
}
}
internal void AddLength (ulong length, byte[] buffer, int position)
{
buffer [position++] = (byte)(length >> 56);
buffer [position++] = (byte)(length >> 48);
buffer [position++] = (byte)(length >> 40);
buffer [position++] = (byte)(length >> 32);
buffer [position++] = (byte)(length >> 24);
buffer [position++] = (byte)(length >> 16);
buffer [position++] = (byte)(length >> 8);
buffer [position] = (byte)(length);
}
}
}
|