Class SipHash

core/src/main/java/org/bouncycastle/crypto/macs/SipHash.java:18–216

Implementation of SipHash as specified in "SipHash: a fast short-input PRF", by Jean-Philippe Aumasson and Daniel J. Bernstein (https://131002.net/siphash/siphash.pdf). "SipHash is a family of PRFs SipHash-c-d where the integer parameters c and d are the number of compression rounds and the numb

 * (possibly empty) byte string m, SipHash-c-d returns a 64-bit value..."
 */
public class SipHash
    implements Mac
{
    protected final int c, d;

    protected long k0, k1;
    protected long v0, v1, v2, v3;

    protected long m = 0;
    protected int wordPos = 0;
    protected int wordCount = 0;

    /**
     * SipHash-2-4
     */
    public SipHash()
    {
        // use of 'this' confuses the flow analyser on earlier JDKs.
        this.c = 2;
        this.d = 4;
    }

    /**
     * SipHash-c-d
     *
     * @param c the number of compression rounds
     * @param d the number of finalization rounds
     */
    public SipHash(int c, int d)
    {
        this.c = c;
        this.d = d;
    }

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

    public int getMacSize()
    {
        return 8;
    }

    public void init(CipherParameters params)
        throws IllegalArgumentException
    {
        if (!(params instanceof KeyParameter))
        {
            throw new IllegalArgumentException("'params' must be an instance of KeyParameter");
        }
        KeyParameter keyParameter = (KeyParameter)params;
        byte[] key = keyParameter.getKey();
        if (key.length != 16)
        {
            throw new IllegalArgumentException("'params' must be a 128-bit key");
        }