package org.bouncycastle.crypto.digests;import org.bouncycastle.crypto.Digest;/** * Draft FIPS 180-2 implementation of SHA-512. <b>Note:</b> As this is * based on a draft this implementation is subject to change. * * <pre> *         block  word  digest * SHA-1   512    32    160 * SHA-256 512    32    256 * SHA-384 1024   64    384 * SHA-512 1024   64    512 * </pre> */public class SHA512Digest    extends LongDigest{    private static final int    DIGEST_LENGTH = 64;	/**	 * Standard constructor	 */    public SHA512Digest()    {    }	/**	 * Copy constructor.  This will copy the state of the provided	 * message digest.	 */	public SHA512Digest(SHA512Digest t)	{		super(t);	}    public String getAlgorithmName()    {        return "SHA-512";    }    public int getDigestSize()    {        return DIGEST_LENGTH;    }    public int doFinal(        byte[]  out,        int     outOff)    {        finish();        unpackWord(H1, out, outOff);        unpackWord(H2, out, outOff + 8);        unpackWord(H3, out, outOff + 16);        unpackWord(H4, out, outOff + 24);        unpackWord(H5, out, outOff + 32);        unpackWord(H6, out, outOff + 40);        unpackWord(H7, out, outOff + 48);        unpackWord(H8, out, outOff + 56);        reset();        return DIGEST_LENGTH;    }    /**     * reset the chaining variables     */    public void reset()    {        super.reset();		/* SHA-512 initial hash value		 * The first 64 bits of the fractional parts of the square roots		 * of the first eight prime numbers		 */		H1 = 0x6a09e667f3bcc908l;		H2 = 0xbb67ae8584caa73bl;		H3 = 0x3c6ef372fe94f82bl;		H4 = 0xa54ff53a5f1d36f1l;		H5 = 0x510e527fade682d1l;		H6 = 0x9b05688c2b3e6c1fl;		H7 = 0x1f83d9abfb41bd6bl;		H8 = 0x5be0cd19137e2179L;    }}