File	Doc	Category	Size	Date	Package
SHA256Digest.java	API Doc	Azureus 3.0.3.4	5908	Tue Jun 08 05:12:58 BST 2004	org.bouncycastle.crypto.digests

SHA256Digest

• java.lang.Object
  • GeneralDigest

block word digest
SHA-1 512 32 160
SHA-256 512 32 256
SHA-384 1024 64 384
SHA-512 1024 64 512

Fields Summary
private static final int	DIGEST_LENGTH
private int	H1
private int	H2
private int	H3
private int	H4
private int	H5
private int	H6
private int	H7
private int	H8
private int[]	X
private int	xOff
static final int[]	K

Constructors Summary
public SHA256Digest() Standard constructor reset();
public SHA256Digest(SHA256Digest t) Copy constructor. This will copy the state of the provided message digest. super(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;

Methods Summary
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 rotateRight(x, 2) ^ rotateRight(x, 13) ^ rotateRight(x, 22);
private int	Sum1(int x) return rotateRight(x, 6) ^ rotateRight(x, 11) ^ rotateRight(x, 25);
private int	Theta0(int x) return rotateRight(x, 7) ^ rotateRight(x, 18) ^ (x >>> 3);
private int	Theta1(int x) return rotateRight(x, 17) ^ rotateRight(x, 19) ^ (x >>> 10);
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); unpackWord(H6, out, outOff + 20); unpackWord(H7, out, outOff + 24); unpackWord(H8, out, outOff + 28); reset(); return DIGEST_LENGTH;
public java.lang.String	getAlgorithmName() return "SHA-256";
public int	getDigestSize() return DIGEST_LENGTH;
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; for (int t = 0; t <= 63; t++) { int T1, T2; T1 = h + Sum1(e) + Ch(e, f, g) + K[t] + X[t]; T2 = Sum0(a) + Maj(a, b, c); h = g; g = f; f = e; e = d + T1; d = c; c = b; b = a; a = T1 + T2; } 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 != X.length; i++) { X[i] = 0; }
protected void	processLength(long bitLength) if (xOff > 14) { processBlock(); } X[14] = (int)(bitLength >>> 32); X[15] = (int)(bitLength & 0xffffffff);
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(); }
public void	reset() reset the chaining variables 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; }
private int	rotateRight(int x, int n) return (x >>> n) | (x << (32 - n));
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;