using System;
using Org.BouncyCastle.Crypto.Utilities;
namespace Org.BouncyCastle.Crypto.Digests{
/**
* SHA-224 as described in RFC 3874
* <pre>
* block word digest
* SHA-1 512 32 160
* SHA-224 512 32 224
* SHA-256 512 32 256
* SHA-384 1024 64 384
* SHA-512 1024 64 512
* </pre>
*/
public class Sha224Digest
: GeneralDigest
{
private const int DigestLength = 28;
private uint H1, H2, H3, H4, H5, H6, H7, H8;
private uint[] X = new uint[64];
private int xOff;
/**
* Standard constructor
*/
public Sha224Digest()
{
Reset();
}
/**
* Copy constructor. This will copy the state of the provided
* message digest.
*/
public Sha224Digest(
Sha224Digest t)
: base(t)
{
H1 = t.H1;
H2 = t.H2;
H3 = t.H3;
H4 = t.H4;
H5 = t.H5;
H6 = t.H6;
H7 = t.H7;
H8 = t.H8;
Array.Copy(t.X, 0, X, 0, t.X.Length);
xOff = t.xOff;
}
public override string AlgorithmName
{
get { return "SHA-224"; }
}
public override int GetDigestSize()
{
return DigestLength;
}
internal override void ProcessWord(
byte[] input,
int inOff)
{
X[xOff] = Pack.BE_To_UInt32(input, inOff);
if (++xOff == 16)
{
ProcessBlock();
}
}
internal override void ProcessLength(
long bitLength)
{
if (xOff > 14)
{
ProcessBlock();
}
X[14] = (uint)((ulong)bitLength >> 32);
X[15] = (uint)((ulong)bitLength);
}
public override int DoFinal(
byte[] output,
int outOff)
{
Finish();
Pack.UInt32_To_BE(H1, output, outOff);
Pack.UInt32_To_BE(H2, output, outOff + 4);
Pack.UInt32_To_BE(H3, output, outOff + 8);
Pack.UInt32_To_BE(H4, output, outOff + 12);
Pack.UInt32_To_BE(H5, output, outOff + 16);
Pack.UInt32_To_BE(H6, output, outOff + 20);
Pack.UInt32_To_BE(H7, output, outOff + 24);
Reset();
return DigestLength;
}
/**
* reset the chaining variables
*/
public override void Reset()
{
base.Reset();
/* SHA-224 initial hash value
*/
H1 = 0xc1059ed8;
H2 = 0x367cd507;
H3 = 0x3070dd17;
H4 = 0xf70e5939;
H5 = 0xffc00b31;
H6 = 0x68581511;
H7 = 0x64f98fa7;
H8 = 0xbefa4fa4;
xOff = 0;
Array.Clear(X, 0, X.Length);
}
internal override void ProcessBlock()
{
//
// expand 16 word block into 64 word blocks.
//
for (int ti = 16; ti <= 63; ti++)
{
X[ti] = Theta1(X[ti - 2]) + X[ti - 7] + Theta0(X[ti - 15]) + X[ti - 16];
}
//
// set up working variables.
//
uint a = H1;
uint b = H2;
uint c = H3;
uint d = H4;
uint e = H5;
uint f = H6;
uint g = H7;
uint h = H8;
int t = 0;
for(int i = 0; i < 8; i ++)
{
// t = 8 * i
h += Sum1(e) + Ch(e, f, g) + K[t] + X[t];
d += h;
h += Sum0(a) + Maj(a, b, c);
++t;
// t = 8 * i + 1
g += Sum1(d) + Ch(d, e, f) + K[t] + X[t];
c += g;
g += Sum0(h) + Maj(h, a, b);
++t;
// t = 8 * i + 2
f += Sum1(c) + Ch(c, d, e) + K[t] + X[t];
b += f;
f += Sum0(g) + Maj(g, h, a);
++t;
// t = 8 * i + 3
e += Sum1(b) + Ch(b, c, d) + K[t] + X[t];
a += e;
e += Sum0(f) + Maj(f, g, h);
++t;
// t = 8 * i + 4
d += Sum1(a) + Ch(a, b, c) + K[t] + X[t];
h += d;
d += Sum0(e) + Maj(e, f, g);
++t;
// t = 8 * i + 5
c += Sum1(h) + Ch(h, a, b) + K[t] + X[t];
g += c;
c += Sum0(d) + Maj(d, e, f);
++t;
// t = 8 * i + 6
b += Sum1(g) + Ch(g, h, a) + K[t] + X[t];
f += b;
b += Sum0(c) + Maj(c, d, e);
++t;
// t = 8 * i + 7
a += Sum1(f) + Ch(f, g, h) + K[t] + X[t];
e += a;
a += Sum0(b) + Maj(b, c, d);
++t;
}
H1 += a;
H2 += b;
H3 += c;
H4 += d;
H5 += e;
H6 += f;
H7 += g;
H8 += h;
//
// reset the offset and clean out the word buffer.
//
xOff = 0;
Array.Clear(X, 0, 16);
}
/* SHA-224 functions */
private static uint Ch(uint x, uint y, uint z)
{
return (x & y) ^ (~x & z);
}
private static uint Maj(uint x, uint y, uint z)
{
return (x & y) ^ (x & z) ^ (y & z);
}
private static uint Sum0(uint x)
{
return ((x >> 2) | (x << 30)) ^ ((x >> 13) | (x << 19)) ^ ((x >> 22) | (x << 10));
}
private static uint Sum1(uint x)
{
return ((x >> 6) | (x << 26)) ^ ((x >> 11) | (x << 21)) ^ ((x >> 25) | (x << 7));
}
private static uint Theta0(uint x)
{
return ((x >> 7) | (x << 25)) ^ ((x >> 18) | (x << 14)) ^ (x >> 3);
}
private static uint Theta1(uint x)
{
return ((x >> 17) | (x << 15)) ^ ((x >> 19) | (x << 13)) ^ (x >> 10);
}
/* SHA-224 Constants
* (represent the first 32 bits of the fractional parts of the
* cube roots of the first sixty-four prime numbers)
*/
internal static readonly uint[] K = {
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};
}
}
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