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using System;
using Org.BouncyCastle.Crypto.Utilities;
using Org.BouncyCastle.Utilities;
namespace Org.BouncyCastle.Crypto.Digests
{
/**
* implementation of SHA-1 as outlined in "Handbook of Applied Cryptography", pages 346 - 349.
*
* It is interesting to ponder why the, apart from the extra IV, the other difference here from MD5
* is the "endianness" of the word processing!
*/
public class Sha1Digest
: GeneralDigest
{
private const int DigestLength = 20;
private uint H1, H2, H3, H4, H5;
private uint[] X = new uint[80];
private int xOff;
public Sha1Digest()
{
Reset();
}
/**
* Copy constructor. This will copy the state of the provided
* message digest.
*/
public Sha1Digest(Sha1Digest t)
: base(t)
{
CopyIn(t);
}
private void CopyIn(Sha1Digest t)
{
base.CopyIn(t);
H1 = t.H1;
H2 = t.H2;
H3 = t.H3;
H4 = t.H4;
H5 = t.H5;
Array.Copy(t.X, 0, X, 0, t.X.Length);
xOff = t.xOff;
}
public override string AlgorithmName
{
get { return "SHA-1"; }
}
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);
Reset();
return DigestLength;
}
/**
* reset the chaining variables
*/
public override void Reset()
{
base.Reset();
H1 = 0x67452301;
H2 = 0xefcdab89;
H3 = 0x98badcfe;
H4 = 0x10325476;
H5 = 0xc3d2e1f0;
xOff = 0;
Array.Clear(X, 0, X.Length);
}
//
// Additive constants
//
private const uint Y1 = 0x5a827999;
private const uint Y2 = 0x6ed9eba1;
private const uint Y3 = 0x8f1bbcdc;
private const uint Y4 = 0xca62c1d6;
private static uint F(uint u, uint v, uint w)
{
return (u & v) | (~u & w);
}
private static uint H(uint u, uint v, uint w)
{
return u ^ v ^ w;
}
private static uint G(uint u, uint v, uint w)
{
return (u & v) | (u & w) | (v & w);
}
internal override void ProcessBlock()
{
//
// expand 16 word block into 80 word block.
//
for (int i = 16; i < 80; i++)
{
uint t = X[i - 3] ^ X[i - 8] ^ X[i - 14] ^ X[i - 16];
X[i] = t << 1 | t >> 31;
}
//
// set up working variables.
//
uint A = H1;
uint B = H2;
uint C = H3;
uint D = H4;
uint E = H5;
//
// round 1
//
int idx = 0;
for (int j = 0; j < 4; j++)
{
// E = rotateLeft(A, 5) + F(B, C, D) + E + X[idx++] + Y1
// B = rotateLeft(B, 30)
E += (A << 5 | (A >> 27)) + F(B, C, D) + X[idx++] + Y1;
B = B << 30 | (B >> 2);
D += (E << 5 | (E >> 27)) + F(A, B, C) + X[idx++] + Y1;
A = A << 30 | (A >> 2);
C += (D << 5 | (D >> 27)) + F(E, A, B) + X[idx++] + Y1;
E = E << 30 | (E >> 2);
B += (C << 5 | (C >> 27)) + F(D, E, A) + X[idx++] + Y1;
D = D << 30 | (D >> 2);
A += (B << 5 | (B >> 27)) + F(C, D, E) + X[idx++] + Y1;
C = C << 30 | (C >> 2);
}
//
// round 2
//
for (int j = 0; j < 4; j++)
{
// E = rotateLeft(A, 5) + H(B, C, D) + E + X[idx++] + Y2
// B = rotateLeft(B, 30)
E += (A << 5 | (A >> 27)) + H(B, C, D) + X[idx++] + Y2;
B = B << 30 | (B >> 2);
D += (E << 5 | (E >> 27)) + H(A, B, C) + X[idx++] + Y2;
A = A << 30 | (A >> 2);
C += (D << 5 | (D >> 27)) + H(E, A, B) + X[idx++] + Y2;
E = E << 30 | (E >> 2);
B += (C << 5 | (C >> 27)) + H(D, E, A) + X[idx++] + Y2;
D = D << 30 | (D >> 2);
A += (B << 5 | (B >> 27)) + H(C, D, E) + X[idx++] + Y2;
C = C << 30 | (C >> 2);
}
//
// round 3
//
for (int j = 0; j < 4; j++)
{
// E = rotateLeft(A, 5) + G(B, C, D) + E + X[idx++] + Y3
// B = rotateLeft(B, 30)
E += (A << 5 | (A >> 27)) + G(B, C, D) + X[idx++] + Y3;
B = B << 30 | (B >> 2);
D += (E << 5 | (E >> 27)) + G(A, B, C) + X[idx++] + Y3;
A = A << 30 | (A >> 2);
C += (D << 5 | (D >> 27)) + G(E, A, B) + X[idx++] + Y3;
E = E << 30 | (E >> 2);
B += (C << 5 | (C >> 27)) + G(D, E, A) + X[idx++] + Y3;
D = D << 30 | (D >> 2);
A += (B << 5 | (B >> 27)) + G(C, D, E) + X[idx++] + Y3;
C = C << 30 | (C >> 2);
}
//
// round 4
//
for (int j = 0; j < 4; j++)
{
// E = rotateLeft(A, 5) + H(B, C, D) + E + X[idx++] + Y4
// B = rotateLeft(B, 30)
E += (A << 5 | (A >> 27)) + H(B, C, D) + X[idx++] + Y4;
B = B << 30 | (B >> 2);
D += (E << 5 | (E >> 27)) + H(A, B, C) + X[idx++] + Y4;
A = A << 30 | (A >> 2);
C += (D << 5 | (D >> 27)) + H(E, A, B) + X[idx++] + Y4;
E = E << 30 | (E >> 2);
B += (C << 5 | (C >> 27)) + H(D, E, A) + X[idx++] + Y4;
D = D << 30 | (D >> 2);
A += (B << 5 | (B >> 27)) + H(C, D, E) + X[idx++] + Y4;
C = C << 30 | (C >> 2);
}
H1 += A;
H2 += B;
H3 += C;
H4 += D;
H5 += E;
//
// reset start of the buffer.
//
xOff = 0;
Array.Clear(X, 0, 16);
}
public override IMemoable Copy()
{
return new Sha1Digest(this);
}
public override void Reset(IMemoable other)
{
Sha1Digest d = (Sha1Digest)other;
CopyIn(d);
}
}
}