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Spongy Castle is a package-rename (org.bouncycastle.* to org.spongycastle.*) of Bouncy Castle
intended for the Android platform. Android unfortunately ships with a stripped-down version of
Bouncy Castle, which prevents easy upgrades - Spongy Castle overcomes this and provides a full,
up-to-date version of the Bouncy Castle cryptographic libs.
package org.spongycastle.crypto.digests;
import org.spongycastle.util.Memoable;
import org.spongycastle.util.Pack;
/**
* FIPS 180-2 implementation of SHA-256.
*
*
* block word digest
* SHA-1 512 32 160
* SHA-256 512 32 256
* SHA-384 1024 64 384
* SHA-512 1024 64 512
*
*/
public class SHA256Digest
extends GeneralDigest
implements EncodableDigest
{
private static final int DIGEST_LENGTH = 32;
private int H1, H2, H3, H4, H5, H6, H7, H8;
private int[] X = new int[64];
private int xOff;
/**
* Standard constructor
*/
public SHA256Digest()
{
reset();
}
/**
* Copy constructor. This will copy the state of the provided
* message digest.
*/
public SHA256Digest(SHA256Digest t)
{
super(t);
copyIn(t);
}
private void copyIn(SHA256Digest t)
{
super.copyIn(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;
System.arraycopy(t.X, 0, X, 0, t.X.length);
xOff = t.xOff;
}
public SHA256Digest(byte[] encodedState)
{
super(encodedState);
H1 = Pack.bigEndianToInt(encodedState, 16);
H2 = Pack.bigEndianToInt(encodedState, 20);
H3 = Pack.bigEndianToInt(encodedState, 24);
H4 = Pack.bigEndianToInt(encodedState, 28);
H5 = Pack.bigEndianToInt(encodedState, 32);
H6 = Pack.bigEndianToInt(encodedState, 36);
H7 = Pack.bigEndianToInt(encodedState, 40);
H8 = Pack.bigEndianToInt(encodedState, 44);
xOff = Pack.bigEndianToInt(encodedState, 48);
for (int i = 0; i != xOff; i++)
{
X[i] = Pack.bigEndianToInt(encodedState, 52 + (i * 4));
}
}
public String getAlgorithmName()
{
return "SHA-256";
}
public int getDigestSize()
{
return DIGEST_LENGTH;
}
protected void processWord(
byte[] in,
int inOff)
{
// Note: Inlined for performance
// X[xOff] = Pack.bigEndianToInt(in, inOff);
int n = in[inOff] << 24;
n |= (in[++inOff] & 0xff) << 16;
n |= (in[++inOff] & 0xff) << 8;
n |= (in[++inOff] & 0xff);
X[xOff] = n;
if (++xOff == 16)
{
processBlock();
}
}
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();
Pack.intToBigEndian(H1, out, outOff);
Pack.intToBigEndian(H2, out, outOff + 4);
Pack.intToBigEndian(H3, out, outOff + 8);
Pack.intToBigEndian(H4, out, outOff + 12);
Pack.intToBigEndian(H5, out, outOff + 16);
Pack.intToBigEndian(H6, out, outOff + 20);
Pack.intToBigEndian(H7, out, outOff + 24);
Pack.intToBigEndian(H8, out, outOff + 28);
reset();
return DIGEST_LENGTH;
}
/**
* reset the chaining variables
*/
public void reset()
{
super.reset();
/* SHA-256 initial hash value
* The first 32 bits of the fractional parts of the square roots
* of the first eight prime numbers
*/
H1 = 0x6a09e667;
H2 = 0xbb67ae85;
H3 = 0x3c6ef372;
H4 = 0xa54ff53a;
H5 = 0x510e527f;
H6 = 0x9b05688c;
H7 = 0x1f83d9ab;
H8 = 0x5be0cd19;
xOff = 0;
for (int i = 0; i != X.length; i++)
{
X[i] = 0;
}
}
protected void processBlock()
{
//
// expand 16 word block into 64 word blocks.
//
for (int t = 16; t <= 63; t++)
{
X[t] = Theta1(X[t - 2]) + X[t - 7] + Theta0(X[t - 15]) + X[t - 16];
}
//
// set up working variables.
//
int a = H1;
int b = H2;
int c = H3;
int d = H4;
int e = H5;
int f = H6;
int g = H7;
int 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;
for (int i = 0; i < 16; i++)
{
X[i] = 0;
}
}
/* SHA-256 functions */
private int Ch(
int x,
int y,
int z)
{
return (x & y) ^ ((~x) & z);
}
private int Maj(
int x,
int y,
int z)
{
return (x & y) ^ (x & z) ^ (y & z);
}
private int Sum0(
int x)
{
return ((x >>> 2) | (x << 30)) ^ ((x >>> 13) | (x << 19)) ^ ((x >>> 22) | (x << 10));
}
private int Sum1(
int x)
{
return ((x >>> 6) | (x << 26)) ^ ((x >>> 11) | (x << 21)) ^ ((x >>> 25) | (x << 7));
}
private int Theta0(
int x)
{
return ((x >>> 7) | (x << 25)) ^ ((x >>> 18) | (x << 14)) ^ (x >>> 3);
}
private int Theta1(
int x)
{
return ((x >>> 17) | (x << 15)) ^ ((x >>> 19) | (x << 13)) ^ (x >>> 10);
}
/* SHA-256 Constants
* (represent the first 32 bits of the fractional parts of the
* cube roots of the first sixty-four prime numbers)
*/
static final int 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
};
public Memoable copy()
{
return new SHA256Digest(this);
}
public void reset(Memoable other)
{
SHA256Digest d = (SHA256Digest)other;
copyIn(d);
}
public byte[] getEncodedState()
{
byte[] state = new byte[52 + xOff * 4];
super.populateState(state);
Pack.intToBigEndian(H1, state, 16);
Pack.intToBigEndian(H2, state, 20);
Pack.intToBigEndian(H3, state, 24);
Pack.intToBigEndian(H4, state, 28);
Pack.intToBigEndian(H5, state, 32);
Pack.intToBigEndian(H6, state, 36);
Pack.intToBigEndian(H7, state, 40);
Pack.intToBigEndian(H8, state, 44);
Pack.intToBigEndian(xOff, state, 48);
for (int i = 0; i != xOff; i++)
{
Pack.intToBigEndian(X[i], state, 52 + (i * 4));
}
return state;
}
}
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