/* This file is part of "MidpSSH".
*
* This file was adapted from Bouncy Castle JCE (www.bouncycastle.org)
* for MidpSSH by Karl von Randow
*/
package ssh.v2;
/**
* 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 "endienness" of the word processing!
*/
public class SHA1Digest {
private static final int DIGEST_LENGTH = 20;
private int H1, H2, H3, H4, H5;
private int[] X = new int[80];
private int xOff;
private byte[] xBuf;
private int xBufOff;
private long byteCount;
/**
* Standard constructor
*/
public SHA1Digest() {
xBuf = new byte[4];
xBufOff = 0;
reset();
}
public String getAlgorithmName() {
return "SHA-1";
}
public int getDigestSize() {
return DIGEST_LENGTH;
}
protected void processWord(byte[] in, int inOff) {
X[xOff++] = ((in[inOff] & 0xff) << 24) | ((in[inOff + 1] & 0xff) << 16)
| ((in[inOff + 2] & 0xff) << 8) | ((in[inOff + 3] & 0xff));
if (xOff == 16) {
processBlock();
}
}
private void unpackWord(int word, byte[] out, int outOff) {
out[outOff] = (byte) (word >>> 24);
out[outOff + 1] = (byte) (word >>> 16);
out[outOff + 2] = (byte) (word >>> 8);
out[outOff + 3] = (byte) word;
}
protected void processLength(long bitLength) {
if (xOff > 14) {
processBlock();
}
X[14] = (int) (bitLength >>> 32);
X[15] = (int) (bitLength & 0xffffffff);
}
public int doFinal(byte[] out, int outOff) {
finish();
unpackWord(H1, out, outOff);
unpackWord(H2, out, outOff + 4);
unpackWord(H3, out, outOff + 8);
unpackWord(H4, out, outOff + 12);
unpackWord(H5, out, outOff + 16);
reset();
return DIGEST_LENGTH;
}
/**
* reset the chaining variables
*/
public void reset() {
byteCount = 0;
xBufOff = 0;
for (int i = 0; i < xBuf.length; i++) {
xBuf[i] = 0;
}
H1 = 0x67452301;
H2 = 0xefcdab89;
H3 = 0x98badcfe;
H4 = 0x10325476;
H5 = 0xc3d2e1f0;
xOff = 0;
for (int i = 0; i != X.length; i++) {
X[i] = 0;
}
}
public void update(byte in) {
xBuf[xBufOff++] = in;
if (xBufOff == xBuf.length) {
processWord(xBuf, 0);
xBufOff = 0;
}
byteCount++;
}
public void update(byte[] in, int inOff, int len) {
//
// fill the current word
//
while ((xBufOff != 0) && (len > 0)) {
update(in[inOff]);
inOff++;
len--;
}
//
// process whole words.
//
while (len > xBuf.length) {
processWord(in, inOff);
inOff += xBuf.length;
len -= xBuf.length;
byteCount += xBuf.length;
}
//
// load in the remainder.
//
while (len > 0) {
update(in[inOff]);
inOff++;
len--;
}
}
public void finish() {
long bitLength = (byteCount << 3);
//
// add the pad bytes.
//
update((byte) 128);
while (xBufOff != 0) {
update((byte) 0);
}
processLength(bitLength);
processBlock();
}
//
// Additive constants
//
private static final int Y1 = 0x5a827999;
private static final int Y2 = 0x6ed9eba1;
private static final int Y3 = 0x8f1bbcdc;
private static final int Y4 = 0xca62c1d6;
private int f(int u, int v, int w) {
return ((u & v) | ((~u) & w));
}
private int h(int u, int v, int w) {
return (u ^ v ^ w);
}
private int g(int u, int v, int w) {
return ((u & v) | (u & w) | (v & w));
}
private int rotateLeft(int x, int n) {
return (x << n) | (x >>> (32 - n));
}
protected void processBlock() {
//
// expand 16 word block into 80 word block.
//
for (int i = 16; i <= 79; i++) {
X[i] = rotateLeft((X[i - 3] ^ X[i - 8] ^ X[i - 14] ^ X[i - 16]), 1);
}
//
// set up working variables.
//
int A = H1;
int B = H2;
int C = H3;
int D = H4;
int E = H5;
//
// round 1
//
for (int j = 0; j <= 19; j++) {
int t = rotateLeft(A, 5) + f(B, C, D) + E + X[j] + Y1;
E = D;
D = C;
C = rotateLeft(B, 30);
B = A;
A = t;
}
//
// round 2
//
for (int j = 20; j <= 39; j++) {
int t = rotateLeft(A, 5) + h(B, C, D) + E + X[j] + Y2;
E = D;
D = C;
C = rotateLeft(B, 30);
B = A;
A = t;
}
//
// round 3
//
for (int j = 40; j <= 59; j++) {
int t = rotateLeft(A, 5) + g(B, C, D) + E + X[j] + Y3;
E = D;
D = C;
C = rotateLeft(B, 30);
B = A;
A = t;
}
//
// round 4
//
for (int j = 60; j <= 79; j++) {
int t = rotateLeft(A, 5) + h(B, C, D) + E + X[j] + Y4;
E = D;
D = C;
C = rotateLeft(B, 30);
B = A;
A = t;
}
H1 += A;
H2 += B;
H3 += C;
H4 += D;
H5 += E;
//
// reset the offset and clean out the word buffer.
//
xOff = 0;
for (int i = 0; i != X.length; i++) {
X[i] = 0;
}
}
}