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The Bouncy Castle Java APIs for CMS, PKCS, EAC, TSP, CMP, CRMF, OCSP, and certificate generation. This jar contains APIs for JDK 1.5 and up. The APIs can be used in conjunction with a JCE/JCA provider such as the one provided with the Bouncy Castle Cryptography APIs.

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package org.bouncycastle.crypto.macs;

import org.bouncycastle.crypto.DataLengthException;
import org.bouncycastle.util.Pack;

/**
 * Implementation of SipHash with 128 bit output.
 * 
 * Based on the {@link SipHash} and the C reference implementation
 * https://github.com/veorq/SipHash.
 * 
 */
public class SipHash128
    extends SipHash
{

    /**
     * SipHash128-2-4
     */
    public SipHash128()
    {
      super();
    }

    /**
     * SipHash128-c-d
     *
     * @param c the number of compression rounds
     * @param d the number of finalization rounds
     */
    public SipHash128(int c, int d)
    {
       super(c, d);
    }

    public String getAlgorithmName()
    {
        return "SipHash128-" + c + "-" + d;
    }

    public int getMacSize()
    {
        return 16;
    }

    public long doFinal()
        throws DataLengthException, IllegalStateException {
        throw new UnsupportedOperationException("doFinal() is not supported");
    }

    public int doFinal(byte[] out, int outOff)
        throws DataLengthException, IllegalStateException
    {
        // NOTE: 2 distinct shifts to avoid "64-bit shift" when wordPos == 0
        m >>>= ((7 - wordPos) << 3);
        m >>>= 8;
        m |= (((wordCount << 3) + wordPos) & 0xffL) << 56;

        processMessageWord();

        v2 ^= 0xeeL;

        applySipRounds(d);

        long r0 = v0 ^ v1 ^ v2 ^ v3;

        v1 ^= 0xddL;
        applySipRounds(d);

        long r1 = v0 ^ v1 ^ v2 ^ v3;

        reset();

        Pack.longToLittleEndian(r0, out, outOff);
        Pack.longToLittleEndian(r1, out, outOff + 8);
        return 16;
    }

    public void reset()
    {
        super.reset();
        v1 ^= 0xeeL;
    }

}