/**
 * sha3sum – SHA-3 (Keccak) checksum calculator
 * 
 * Copyright © 2013  Mattias Andrée (maandree@member.fsf.org)
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


/**
 * SHA-3/Keccak hash algorithm implementation
 * 
 * @author  Mattias Andrée  <a href="mailto:maandree@member.fsf.org">maandree@member.fsf.org</a>
 */
public class SHA3
{
    /**
     * Round contants
     */
    private static final long[] RC = {
	    0x0000000000000001L, 0x0000000000008082L, 0x800000000000808AL, 0x8000000080008000L,
	    0x000000000000808BL, 0x0000000080000001L, 0x8000000080008081L, 0x8000000000008009L,
	    0x000000000000008AL, 0x0000000000000088L, 0x0000000080008009L, 0x000000008000000AL,
	    0x000000008000808BL, 0x800000000000008BL, 0x8000000000008089L, 0x8000000000008003L,
	    0x8000000000008002L, 0x8000000000000080L, 0x000000000000800AL, 0x800000008000000AL,
	    0x8000000080008081L, 0x8000000000008080L, 0x0000000080000001L, 0x8000000080008008L};
    
    /**
     * Keccak-f round temporary
     */
    private static long[] B = new long[25];
    
    /**
     * Keccak-f round temporary
     */
    private static long[] C = new long[5];
    
    
    /**
     * The bitrate
     */
    private static int r = 0;
    
    /**
     * The capacity
     */
    private static int c = 0;
    
    /**
     * The output size
     */
    private static int n = 0;
    
    /**
     * The state size
     */
    private static int b = 0;
    
    /**
     * The word size
     */
    private static int w = 0;
    
    /**
     * The word mask
     */
    private static long wmod = 0;
    
    /**
     * ℓ, the binary logarithm of the word size
     */
    private static int l = 0;
    
    /**
     * 12 + 2ℓ, the number of rounds
     */
    private static int nr = 0;
    
    
    /**
     * The current state
     */
    private static long[] S = null;
    
    /**
     * Left over water to fill the sponge with at next update
     */
    private static byte[] M = null;
    
    /**
     * Pointer for {@link #M}
     */
    private static int mptr = 0;
    
    
    
    /**
     * Hidden constructor
     */
    private SHA3()
    {
	// Inhibit instansiation
    }
    
    
    
    /**
     * Rotate a word
     * 
     * @param   x  The value to rotate
     * @param   n  Rotation steps
     * @return     The value rotated
     */
    private static long rotate(long x, int n)
    {
        long m = n % SHA3.w;
        return ((x >>> (SHA3.w - m)) + (x << m)) & SHA3.wmod;
    }
    
    
    /**
     * Rotate a 64-bit word
     * 
     * @param   x  The value to rotate
     * @param   n  Rotation steps
     * @return     The value rotated
     */
    private static long rotate64(long x, int n)
    {
        return (x >>> (SHA3.w - n)) + (x << n);
    }
    
    
    /**
     * Binary logarithm
     * 
     * @param   x  The value of which to calculate the binary logarithm
     * @return     The binary logarithm
     */
    private static int lb(int x)
    {
        return (((x & 0xFF00) == 0 ? 0 : 8) +
		((x & 0xF0F0) == 0 ? 0 : 4)) +
	       (((x & 0xCCCC) == 0 ? 0 : 2) +
		((x & 0xAAAA) == 0 ? 0 : 1));
    }
    
    /**
     * Perform one round of computation
     * 
     * @param  A   The current state
     * @param  rc  Round constant
     */
    private static void keccakFRound(long[] A, long rc)
    {
        if (SHA3.w == 64)
	{
            /* θ step (step 1 and 2 of 3) */
            SHA3.C[0] = (A[0]  ^ A[1])  ^ (A[2]  ^ A[3])  ^ A[4];
            SHA3.C[2] = (A[10] ^ A[11]) ^ (A[12] ^ A[13]) ^ A[14];
            long db = SHA3.C[0] ^ SHA3.rotate64(SHA3.C[2], 1);
            SHA3.C[4] = (A[20] ^ A[21]) ^ (A[22] ^ A[23]) ^ A[24];
            long dd = SHA3.C[2] ^ SHA3.rotate64(SHA3.C[4], 1);
            SHA3.C[1] = (A[5]  ^ A[6])  ^ (A[7]  ^ A[8])  ^ A[9];
            long da = SHA3.C[4] ^ SHA3.rotate64(SHA3.C[1], 1);
            SHA3.C[3] = (A[15] ^ A[16]) ^ (A[17] ^ A[18]) ^ A[19];
            long dc = SHA3.C[1] ^ SHA3.rotate64(SHA3.C[3], 1);
            long de = SHA3.C[3] ^ SHA3.rotate64(SHA3.C[0], 1);
            
            /* ρ and π steps, with last part of θ */
            SHA3.B[0] = SHA3.rotate64(A[0] ^ da, 0);
            SHA3.B[1] = SHA3.rotate64(A[15] ^ dd, 28);
            SHA3.B[2] = SHA3.rotate64(A[5] ^ db, 1);
            SHA3.B[3] = SHA3.rotate64(A[20] ^ de, 27);
            SHA3.B[4] = SHA3.rotate64(A[10] ^ dc, 62);
            
            SHA3.B[5] = SHA3.rotate64(A[6] ^ db, 44);
            SHA3.B[6] = SHA3.rotate64(A[21] ^ de, 20);
            SHA3.B[7] = SHA3.rotate64(A[11] ^ dc, 6);
            SHA3.B[8] = SHA3.rotate64(A[1] ^ da, 36);
            SHA3.B[9] = SHA3.rotate64(A[16] ^ dd, 55);
            
            SHA3.B[10] = SHA3.rotate64(A[12] ^ dc, 43);
            SHA3.B[11] = SHA3.rotate64(A[2] ^ da, 3);
            SHA3.B[12] = SHA3.rotate64(A[17] ^ dd, 25);
            SHA3.B[13] = SHA3.rotate64(A[7] ^ db, 10);
            SHA3.B[14] = SHA3.rotate64(A[22] ^ de, 39);
            
            SHA3.B[15] = SHA3.rotate64(A[18] ^ dd, 21);
            SHA3.B[16] = SHA3.rotate64(A[8] ^ db, 45);
            SHA3.B[17] = SHA3.rotate64(A[23] ^ de, 8);
            SHA3.B[18] = SHA3.rotate64(A[13] ^ dc, 15);
            SHA3.B[19] = SHA3.rotate64(A[3] ^ da, 41);
            
            SHA3.B[20] = SHA3.rotate64(A[24] ^ de, 14);
            SHA3.B[21] = SHA3.rotate64(A[14] ^ dc, 61);
            SHA3.B[22] = SHA3.rotate64(A[4] ^ da, 18);
            SHA3.B[23] = SHA3.rotate64(A[19] ^ dd, 56);
            SHA3.B[24] = SHA3.rotate64(A[9] ^ db, 2);
	}
        else
	{
            /* θ step (step 1 and 2 of 3) */
            SHA3.C[0] = (A[0]  ^ A[1])  ^ (A[2]  ^ A[3])  ^ A[4];
            SHA3.C[2] = (A[10] ^ A[11]) ^ (A[12] ^ A[13]) ^ A[14];
            long db = SHA3.C[0] ^ SHA3.rotate(SHA3.C[2], 1);
            SHA3.C[4] = (A[20] ^ A[21]) ^ (A[22] ^ A[23]) ^ A[24];
            long dd = SHA3.C[2] ^ SHA3.rotate(SHA3.C[4], 1);
            SHA3.C[1] = (A[5]  ^ A[6])  ^ (A[7]  ^ A[8])  ^ A[9];
            long da = SHA3.C[4] ^ SHA3.rotate(SHA3.C[1], 1);
            SHA3.C[3] = (A[15] ^ A[16]) ^ (A[17] ^ A[18]) ^ A[19];
            long dc = SHA3.C[1] ^ SHA3.rotate(SHA3.C[3], 1);
            long de = SHA3.C[3] ^ SHA3.rotate(SHA3.C[0], 1);
            
            /*ρ and π steps, with last part of θ */
            SHA3.B[0] = SHA3.rotate(A[0] ^ da, 0);
            SHA3.B[1] = SHA3.rotate(A[15] ^ dd, 28);
            SHA3.B[2] = SHA3.rotate(A[5] ^ db, 1);
            SHA3.B[3] = SHA3.rotate(A[20] ^ de, 27);
            SHA3.B[4] = SHA3.rotate(A[10] ^ dc, 62);
            
            SHA3.B[5] = SHA3.rotate(A[6] ^ db, 44);
            SHA3.B[6] = SHA3.rotate(A[21] ^ de, 20);
            SHA3.B[7] = SHA3.rotate(A[11] ^ dc, 6);
            SHA3.B[8] = SHA3.rotate(A[1] ^ da, 36);
            SHA3.B[9] = SHA3.rotate(A[16] ^ dd, 55);
            
            SHA3.B[10] = SHA3.rotate(A[12] ^ dc, 43);
            SHA3.B[11] = SHA3.rotate(A[2] ^ da, 3);
            SHA3.B[12] = SHA3.rotate(A[17] ^ dd, 25);
	    SHA3.B[13] = SHA3.rotate(A[7] ^ db, 10);
            SHA3.B[14] = SHA3.rotate(A[22] ^ de, 39);
            
            SHA3.B[15] = SHA3.rotate(A[18] ^ dd, 21);
            SHA3.B[16] = SHA3.rotate(A[8] ^ db, 45);
            SHA3.B[17] = SHA3.rotate(A[23] ^ de, 8);
            SHA3.B[18] = SHA3.rotate(A[13] ^ dc, 15);
            SHA3.B[19] = SHA3.rotate(A[3] ^ da, 41);
            
            SHA3.B[20] = SHA3.rotate(A[24] ^ de, 14);
            SHA3.B[21] = SHA3.rotate(A[14] ^ dc, 61);
            SHA3.B[22] = SHA3.rotate(A[4] ^ da, 18);
            SHA3.B[23] = SHA3.rotate(A[19] ^ dd, 56);
            SHA3.B[24] = SHA3.rotate(A[9] ^ db, 2);
	}
	
        /* ξ step */
        A[0] = SHA3.B[0] ^ ((~(SHA3.B[5])) & SHA3.B[10]);
        A[1] = SHA3.B[1] ^ ((~(SHA3.B[6])) & SHA3.B[11]);
        A[2] = SHA3.B[2] ^ ((~(SHA3.B[7])) & SHA3.B[12]);
        A[3] = SHA3.B[3] ^ ((~(SHA3.B[8])) & SHA3.B[13]);
        A[4] = SHA3.B[4] ^ ((~(SHA3.B[9])) & SHA3.B[14]);
        
        A[5] = SHA3.B[5] ^ ((~(SHA3.B[10])) & SHA3.B[15]);
        A[6] = SHA3.B[6] ^ ((~(SHA3.B[11])) & SHA3.B[16]);
        A[7] = SHA3.B[7] ^ ((~(SHA3.B[12])) & SHA3.B[17]);
        A[8] = SHA3.B[8] ^ ((~(SHA3.B[13])) & SHA3.B[18]);
        A[9] = SHA3.B[9] ^ ((~(SHA3.B[14])) & SHA3.B[19]);
        
        A[10] = SHA3.B[10] ^ ((~(SHA3.B[15])) & SHA3.B[20]);
        A[11] = SHA3.B[11] ^ ((~(SHA3.B[16])) & SHA3.B[21]);
        A[12] = SHA3.B[12] ^ ((~(SHA3.B[17])) & SHA3.B[22]);
        A[13] = SHA3.B[13] ^ ((~(SHA3.B[18])) & SHA3.B[23]);
        A[14] = SHA3.B[14] ^ ((~(SHA3.B[19])) & SHA3.B[24]);
        
        A[15] = SHA3.B[15] ^ ((~(SHA3.B[20])) & SHA3.B[0]);
        A[16] = SHA3.B[16] ^ ((~(SHA3.B[21])) & SHA3.B[1]);
        A[17] = SHA3.B[17] ^ ((~(SHA3.B[22])) & SHA3.B[2]);
        A[18] = SHA3.B[18] ^ ((~(SHA3.B[23])) & SHA3.B[3]);
        A[19] = SHA3.B[19] ^ ((~(SHA3.B[24])) & SHA3.B[4]);
        
        A[20] = SHA3.B[20] ^ ((~(SHA3.B[0])) & SHA3.B[5]);
        A[21] = SHA3.B[21] ^ ((~(SHA3.B[1])) & SHA3.B[6]);
        A[22] = SHA3.B[22] ^ ((~(SHA3.B[2])) & SHA3.B[7]);
        A[23] = SHA3.B[23] ^ ((~(SHA3.B[3])) & SHA3.B[8]);
        A[24] = SHA3.B[24] ^ ((~(SHA3.B[4])) & SHA3.B[9]);
        
        /* ι step */
        A[0] ^= rc;
    }
    
    
    /**
     * Perform Keccak-f function
     * 
     * @param  A  The current state
     */
    private static void keccakF(long[] A)
    {
        if (SHA3.nr == 24)
	{
            SHA3.keccakFRound(A, 0x0000000000000001L);
            SHA3.keccakFRound(A, 0x0000000000008082L);
            SHA3.keccakFRound(A, 0x800000000000808AL);
            SHA3.keccakFRound(A, 0x8000000080008000L);
            SHA3.keccakFRound(A, 0x000000000000808BL);
            SHA3.keccakFRound(A, 0x0000000080000001L);
            SHA3.keccakFRound(A, 0x8000000080008081L);
            SHA3.keccakFRound(A, 0x8000000000008009L);
            SHA3.keccakFRound(A, 0x000000000000008AL);
            SHA3.keccakFRound(A, 0x0000000000000088L);
            SHA3.keccakFRound(A, 0x0000000080008009L);
            SHA3.keccakFRound(A, 0x000000008000000AL);
            SHA3.keccakFRound(A, 0x000000008000808BL);
            SHA3.keccakFRound(A, 0x800000000000008BL);
            SHA3.keccakFRound(A, 0x8000000000008089L);
            SHA3.keccakFRound(A, 0x8000000000008003L);
            SHA3.keccakFRound(A, 0x8000000000008002L);
            SHA3.keccakFRound(A, 0x8000000000000080L);
            SHA3.keccakFRound(A, 0x000000000000800AL);
            SHA3.keccakFRound(A, 0x800000008000000AL);
	    SHA3.keccakFRound(A, 0x8000000080008081L);
	    SHA3.keccakFRound(A, 0x8000000000008080L);
	    SHA3.keccakFRound(A, 0x0000000080000001L);
	    SHA3.keccakFRound(A, 0x8000000080008008L);
	}
        else
            for (int i = 0; i < SHA3.nr; i++)
		SHA3.keccakFRound(A, SHA3.RC[i] & SHA3.wmod);
    }
    
    
    /**
     * Convert a chunk of byte:s to a word
     * 
     * @param   message  The message
     * @param   rr       Bitrate in bytes
     * @param   ww       Word size in bytes
     * @param   off      The offset in the message
     * @return           Lane
     */
    private static long toLane(byte[] message, int rr, int ww, int off)
    {
        int n = Math.min(message.length, rr), rc = 0;
        for (int i = off + ww - 1; i >= off; i--)
            rc = (rc << 8) | ((i < n) ? message[i] : 0);
        return rc;
    }
    
    
    /**
     * Convert a chunk of byte:s to a 64-bit word
     * 
     * @param   message  The message
     * @param   rr       Bitrate in bytes
     * @param   off      The offset in the message
     * @return           Lane
     */
    private static long toLane64(byte[] message, int rr, int off)
    {
        int n = Math.min(message.length, rr), rc = 0;
        return ((off + 7 < n) ? (message[off + 7] << 56) : 0) |
	       ((off + 6 < n) ? (message[off + 6] << 48) : 0) |
	       ((off + 5 < n) ? (message[off + 5] << 40) : 0) |
	       ((off + 4 < n) ? (message[off + 4] << 32) : 0) |
	       ((off + 3 < n) ? (message[off + 3] << 24) : 0) |
	       ((off + 2 < n) ? (message[off + 2] << 16) : 0) |
	       ((off + 1 < n) ? (message[off + 1] <<  8) : 0) |
	       ((off < n) ? (message[off]) : 0);
    }
    
    
    /**
     * pad 10*1
     * 
     * @param   msg  The message to pad
     * @parm    len  The length of the message
     * @param   r    The bitrate
     * @return       The message padded
     */
    private static byte[] pad10star1(byte[] msg, int len, int r)
    {
        int nrf = len >> 3;
        int nbrf = len & 7;
        int ll = len % r;
        
        byte b = (byte)(nbrf == 0 ? 1 : ((msg[nrf] >> (8 - nbrf)) | (1 << nbrf)));
        
        byte[] message;
        if ((r - 8 <= ll) && (ll <= r - 2))
	{
	    message = new byte[len = nrf + 1];
            message[nrf] = (byte)(b ^ 128);
	}
        else
	{
	    len = (nrf + 1) << 3;
	    len = ((len - (len % r) + (r - 8)) >> 3) + 1;
	    message = new byte[len];
	    message[nrf] = b;
	    //for (long i = nrf + 1; i < len; i++)
	    //    message[i + nrf] = 0;
	    message[len - 1] = -128;
	}
	for (int i = 0; i < nrf; i++)
	    message[i] = msg[i];
        
        return message;
    }
    
    
    /**
     * Initialise Keccak sponge
     * 
     * @param  r  The bitrate
     * @param  c  The capacity
     * @param  n  The output size
     */
    public static void initialise(int r, int c, int n)
    {
        SHA3.r = r;
        SHA3.c = c;
        SHA3.n = n;
        SHA3.b = r + c;
        SHA3.w = SHA3.b / 25;
        SHA3.l = SHA3.lb(SHA3.w);
        SHA3.nr = 12 + (SHA3.l << 1);
        SHA3.wmod = (1L << SHA3.w) - 1L;
        SHA3.S = new long[25];
        SHA3.M = new byte[(SHA3.r * SHA3.b) >> 2];
	SHA3.mptr = 0;
    }
    
    
    /**
     * Absorb the more of the message message to the Keccak sponge
     * 
     * @param  msg  The partial message
     */
    public static void update(byte[] msg)
    {
	update(msg, msg.length);
    }
    
    
    /**
     * Absorb the more of the message message to the Keccak sponge
     * 
     * @param  msg     The partial message
     * @param  msglen  The length of the partial message
     */
    public static void update(byte[] msg, int msglen)
    {
        int rr = SHA3.r >> 3;
        int ww = SHA3.w >> 3;
        
	if (SHA3.mptr + msglen > SHA3.M.length)
	    System.arraycopy(SHA3.M, 0, SHA3.M = new byte[(SHA3.M.length + msglen) << 1], 0, SHA3.mptr);
	System.arraycopy(msg, 0, SHA3.M, SHA3.mptr, msglen);
	SHA3.mptr += msglen;
        int len = SHA3.mptr;
        len -= len % ((SHA3.r * SHA3.b) >> 3);
        byte[] message;
	System.arraycopy(SHA3.M, 0, message = new byte[len], 0, len);
	System.arraycopy(SHA3.M, len, SHA3.M, 0, SHA3.mptr -= len);
	
        /* Absorbing phase */
        if (ww == 8)
            for (int i = 0; i < len; i += rr)
	    {
		SHA3.S[ 0] ^= SHA3.toLane64(message, rr, i + 0);
		SHA3.S[ 5] ^= SHA3.toLane64(message, rr, i + 8);
		SHA3.S[10] ^= SHA3.toLane64(message, rr, i + 16);
                SHA3.S[15] ^= SHA3.toLane64(message, rr, i + 24);
                SHA3.S[20] ^= SHA3.toLane64(message, rr, i + 32);
                SHA3.S[ 1] ^= SHA3.toLane64(message, rr, i + 40);
                SHA3.S[ 6] ^= SHA3.toLane64(message, rr, i + 48);
                SHA3.S[11] ^= SHA3.toLane64(message, rr, i + 56);
                SHA3.S[16] ^= SHA3.toLane64(message, rr, i + 64);
                SHA3.S[21] ^= SHA3.toLane64(message, rr, i + 72);
                SHA3.S[ 2] ^= SHA3.toLane64(message, rr, i + 80);
                SHA3.S[ 7] ^= SHA3.toLane64(message, rr, i + 88);
		SHA3.S[12] ^= SHA3.toLane64(message, rr, i + 96);
		SHA3.S[17] ^= SHA3.toLane64(message, rr, i + 104);
		SHA3.S[22] ^= SHA3.toLane64(message, rr, i + 112);
		SHA3.S[ 3] ^= SHA3.toLane64(message, rr, i + 120);
		SHA3.S[ 8] ^= SHA3.toLane64(message, rr, i + 128);
		SHA3.S[13] ^= SHA3.toLane64(message, rr, i + 136);
		SHA3.S[18] ^= SHA3.toLane64(message, rr, i + 144);
		SHA3.S[23] ^= SHA3.toLane64(message, rr, i + 152);
                SHA3.S[ 4] ^= SHA3.toLane64(message, rr, i + 160);
                SHA3.S[ 9] ^= SHA3.toLane64(message, rr, i + 168);
                SHA3.S[14] ^= SHA3.toLane64(message, rr, i + 176);
                SHA3.S[19] ^= SHA3.toLane64(message, rr, i + 184);
                SHA3.S[24] ^= SHA3.toLane64(message, rr, i + 192);
		SHA3.keccakF(SHA3.S);
	    }
        else
	    for (int i = 0; i < len; i += rr)
	    {
		SHA3.S[ 0] ^= SHA3.toLane(message, rr, ww, i +  0    );
		SHA3.S[ 5] ^= SHA3.toLane(message, rr, ww, i +      w);
		SHA3.S[10] ^= SHA3.toLane(message, rr, ww, i +  2 * w);
                SHA3.S[15] ^= SHA3.toLane(message, rr, ww, i +  3 * w);
                SHA3.S[20] ^= SHA3.toLane(message, rr, ww, i +  4 * w);
                SHA3.S[ 1] ^= SHA3.toLane(message, rr, ww, i +  5 * w);
                SHA3.S[ 6] ^= SHA3.toLane(message, rr, ww, i +  6 * w);
                SHA3.S[11] ^= SHA3.toLane(message, rr, ww, i +  7 * w);
                SHA3.S[16] ^= SHA3.toLane(message, rr, ww, i +  8 * w);
                SHA3.S[21] ^= SHA3.toLane(message, rr, ww, i +  9 * w);
                SHA3.S[ 2] ^= SHA3.toLane(message, rr, ww, i + 10 * w);
                SHA3.S[ 7] ^= SHA3.toLane(message, rr, ww, i + 11 * w);
		SHA3.S[12] ^= SHA3.toLane(message, rr, ww, i + 12 * w);
		SHA3.S[17] ^= SHA3.toLane(message, rr, ww, i + 13 * w);
		SHA3.S[22] ^= SHA3.toLane(message, rr, ww, i + 14 * w);
		SHA3.S[ 3] ^= SHA3.toLane(message, rr, ww, i + 15 * w);
		SHA3.S[ 8] ^= SHA3.toLane(message, rr, ww, i + 16 * w);
		SHA3.S[13] ^= SHA3.toLane(message, rr, ww, i + 17 * w);
		SHA3.S[18] ^= SHA3.toLane(message, rr, ww, i + 18 * w);
		SHA3.S[23] ^= SHA3.toLane(message, rr, ww, i + 19 * w);
                SHA3.S[ 4] ^= SHA3.toLane(message, rr, ww, i + 20 * w);
                SHA3.S[ 9] ^= SHA3.toLane(message, rr, ww, i + 21 * w);
                SHA3.S[14] ^= SHA3.toLane(message, rr, ww, i + 22 * w);
                SHA3.S[19] ^= SHA3.toLane(message, rr, ww, i + 23 * w);
                SHA3.S[24] ^= SHA3.toLane(message, rr, ww, i + 24 * w);
		SHA3.keccakF(SHA3.S);
	    }
    }
    
    
    /**
     * Squeeze the Keccak sponge
     */
    public static byte[] digest()
    {
	return digest(null);
    }
    
    
    /**
     * Absorb the last part of the message and squeeze the Keccak sponge
     * 
     * @param  msg  The rest of the message
     */
    public static byte[] digest(byte[] msg)
    {
	return digest(msg, msg == null ? 0 : msg.length);
    }
    
    
    /**
     * Absorb the last part of the message and squeeze the Keccak sponge
     * 
     * @param  msg     The rest of the message
     * @param  msglen  The length of the partial message
     */
    public static byte[] digest(byte[] msg, int msglen)
    {
	byte[] message;
        if ((msg == null) || (msglen == 0))
            message = SHA3.pad10star1(SHA3.M, SHA3.mptr, SHA3.r);
	else
	{
	    if (SHA3.mptr + msglen > SHA3.M.length)
		System.arraycopy(SHA3.M, 0, SHA3.M = new byte[SHA3.M.length << 1], 0, SHA3.mptr);
	    System.arraycopy(msg, 0, SHA3.M, SHA3.mptr, msglen);
	    message = SHA3.pad10star1(SHA3.M, SHA3.mptr + msglen, SHA3.r);
	}
        SHA3.M = null;
        int len = message.length;
        byte[] rc = new byte[(SHA3.n + 7) >> 3];
        int ptr = 0;
        
        int rr = SHA3.r >> 3;
        int nn = SHA3.n >> 3;
        int ww = SHA3.w >> 3;
        
        /* Absorbing phase */
        if (ww == 8)
            for (int i = 0; i < len; i += rr)
	    {
		SHA3.S[ 0] ^= SHA3.toLane64(message, rr, i + 0);
		SHA3.S[ 5] ^= SHA3.toLane64(message, rr, i + 8);
		SHA3.S[10] ^= SHA3.toLane64(message, rr, i + 16);
                SHA3.S[15] ^= SHA3.toLane64(message, rr, i + 24);
                SHA3.S[20] ^= SHA3.toLane64(message, rr, i + 32);
                SHA3.S[ 1] ^= SHA3.toLane64(message, rr, i + 40);
                SHA3.S[ 6] ^= SHA3.toLane64(message, rr, i + 48);
                SHA3.S[11] ^= SHA3.toLane64(message, rr, i + 56);
                SHA3.S[16] ^= SHA3.toLane64(message, rr, i + 64);
                SHA3.S[21] ^= SHA3.toLane64(message, rr, i + 72);
                SHA3.S[ 2] ^= SHA3.toLane64(message, rr, i + 80);
                SHA3.S[ 7] ^= SHA3.toLane64(message, rr, i + 88);
		SHA3.S[12] ^= SHA3.toLane64(message, rr, i + 96);
		SHA3.S[17] ^= SHA3.toLane64(message, rr, i + 104);
		SHA3.S[22] ^= SHA3.toLane64(message, rr, i + 112);
		SHA3.S[ 3] ^= SHA3.toLane64(message, rr, i + 120);
		SHA3.S[ 8] ^= SHA3.toLane64(message, rr, i + 128);
		SHA3.S[13] ^= SHA3.toLane64(message, rr, i + 136);
		SHA3.S[18] ^= SHA3.toLane64(message, rr, i + 144);
		SHA3.S[23] ^= SHA3.toLane64(message, rr, i + 152);
                SHA3.S[ 4] ^= SHA3.toLane64(message, rr, i + 160);
                SHA3.S[ 9] ^= SHA3.toLane64(message, rr, i + 168);
                SHA3.S[14] ^= SHA3.toLane64(message, rr, i + 176);
                SHA3.S[19] ^= SHA3.toLane64(message, rr, i + 184);
                SHA3.S[24] ^= SHA3.toLane64(message, rr, i + 192);
                SHA3.keccakF(SHA3.S);
	    }
        else
	    for (int i = 0; i < len; i += rr)
	    {
		SHA3.S[ 0] ^= SHA3.toLane(message, rr, ww, i +  0    );
		SHA3.S[ 5] ^= SHA3.toLane(message, rr, ww, i +      w);
		SHA3.S[10] ^= SHA3.toLane(message, rr, ww, i +  2 * w);
                SHA3.S[15] ^= SHA3.toLane(message, rr, ww, i +  3 * w);
                SHA3.S[20] ^= SHA3.toLane(message, rr, ww, i +  4 * w);
                SHA3.S[ 1] ^= SHA3.toLane(message, rr, ww, i +  5 * w);
                SHA3.S[ 6] ^= SHA3.toLane(message, rr, ww, i +  6 * w);
                SHA3.S[11] ^= SHA3.toLane(message, rr, ww, i +  7 * w);
                SHA3.S[16] ^= SHA3.toLane(message, rr, ww, i +  8 * w);
                SHA3.S[21] ^= SHA3.toLane(message, rr, ww, i +  9 * w);
                SHA3.S[ 2] ^= SHA3.toLane(message, rr, ww, i + 10 * w);
                SHA3.S[ 7] ^= SHA3.toLane(message, rr, ww, i + 11 * w);
		SHA3.S[12] ^= SHA3.toLane(message, rr, ww, i + 12 * w);
		SHA3.S[17] ^= SHA3.toLane(message, rr, ww, i + 13 * w);
		SHA3.S[22] ^= SHA3.toLane(message, rr, ww, i + 14 * w);
		SHA3.S[ 3] ^= SHA3.toLane(message, rr, ww, i + 15 * w);
		SHA3.S[ 8] ^= SHA3.toLane(message, rr, ww, i + 16 * w);
		SHA3.S[13] ^= SHA3.toLane(message, rr, ww, i + 17 * w);
		SHA3.S[18] ^= SHA3.toLane(message, rr, ww, i + 18 * w);
		SHA3.S[23] ^= SHA3.toLane(message, rr, ww, i + 19 * w);
                SHA3.S[ 4] ^= SHA3.toLane(message, rr, ww, i + 20 * w);
                SHA3.S[ 9] ^= SHA3.toLane(message, rr, ww, i + 21 * w);
                SHA3.S[14] ^= SHA3.toLane(message, rr, ww, i + 22 * w);
                SHA3.S[19] ^= SHA3.toLane(message, rr, ww, i + 23 * w);
                SHA3.S[24] ^= SHA3.toLane(message, rr, ww, i + 24 * w);
		SHA3.keccakF(SHA3.S);
	    }
        
        /* Squeezing phase */
        int olen = SHA3.n;
        int j = 0;
        int ni = Math.min(25, rr);
        while (olen > 0)
	{
            int i = 0;
	    while ((i < ni) && (j < nn))
	    {
		long v = SHA3.S[i];
		for (int _ = 0; _ < ww; _++)
		{
                    if (j < nn)
		    {
			rc[ptr] = (byte)v;
                        ptr += 1;
		    }
                    v >>= 8;
                    j += 1;
		}
                i += 1;
	    }
            olen -= SHA3.r;
	    if (olen > 0)
		SHA3.keccakF(S);
	}
        return rc;
    }
    
}