// $Id: SHA1.java 3956 2010-01-05 20:56:56Z zacheiss $

/*
 * Copyright (c) 1995-1997 Systemics Ltd
 * on behalf of the Cryptix Development Team.  All rights reserved.
 */

package mit.random;

import java.io.PrintStream;
import mit.cipher.MITCipherException;
import mit.cipher.Hex;

/**
 * This class implements the SHA-1 message digest algorithm.
 * <p>
 * <b>BUG</b>: The update method is missing.
 * <p>
 * <b>References:</b>
 * <ol>
 *   <li> Bruce Schneier,
 *        "Section 18.7 Secure Hash Algorithm (SHA),"
 *        <cite>Applied Cryptography, 2nd edition</cite>,
 *        John Wiley &amp; Sons, 1996
 *        <p>
 *   <li> NIST FIPS PUB 180-1,
 *        "Secure Hash Standard",
 *        U.S. Department of Commerce, May 1993.<br>
 *        <a href="http://www.itl.nist.gov/div897/pubs/fip180-1.htm">
 *        http://www.itl.nist.gov/div897/pubs/fip180-1.htm</a>
 * </ol>
 * <p>
 * <b>Copyright</b> &copy; 1995-1997
 * <a href="http://www.systemics.com/">Systemics Ltd</a> on behalf of the
 * <a href="http://www.systemics.com/docs/cryptix/">Cryptix Development Team</a>.
 * <br>All rights reserved.
 * <p>
 * <b>$Revision: 1.1 $</b>
 * @author Systemics Ltd
 * @author David Hopwood
 * @since  Cryptix 2.2.2
 */
public final class SHA1
{

// Debugging methods and vars.
//...........................................................................

    private static final boolean DEBUG = false;
    private static final boolean DEBUG_SLOW = false;
    private static final PrintStream err = DEBUG ? System.err : null;
    private static void debug(String s) {if (DEBUG) { err.println("SHA-1: " + s); }}


// SHA-1 constants and variables
//...........................................................................

    /**
     * Length of the final hash (in bytes).
     */
    private static final int HASH_LENGTH = 20;

    /**
     * Length of a block (i.e. the number of bytes hashed in every transform).
     */
    private static final int DATA_LENGTH = 64;

    private int[] data;
    private int[] digest;
    private byte[] tmp;
    private int[] w;

    /**
     * Returns the length of the hash (in bytes).
     */
  //    protected int engineGetDigestLength() {
  //        return HASH_LENGTH;
  //    }

    /**
     * Returns the length of the data (in bytes) hashed in every transform.
     */
  //    protected int engineGetDataLength()
  //    {
  //        return DATA_LENGTH;
  //    }

    /**
     * Constructs a SHA-1 message digest.
     */
    public SHA1()
    {
        java_init();
        java_reset();
    }

    private void java_init()
    {
        digest = new int[HASH_LENGTH/4];
        data = new int[DATA_LENGTH/4];
        tmp = new byte[DATA_LENGTH];
        w = new int[80];
    }

    /**
     * Initializes (resets) the message digest.
     */
    protected void engineReset()
    {
      //          super.engineReset();
          java_reset();
    }

    private void java_reset()
    {
        digest[0] = 0x67452301;
        digest[1] = 0xefcdab89;
        digest[2] = 0x98badcfe;
        digest[3] = 0x10325476;
        digest[4] = 0xc3d2e1f0;
    }

    /**
     * Adds data to the message digest.
     *
     * @param in      Array of bytes to be added
     */
    public void Update(byte[] in)
    {
        byte b[] = java_digest(in, in.length);
    }

    private void java_transform(byte[] in)
    {
        byte2int(in, 0, data, 0, DATA_LENGTH/4);
        transform(data);
    }

    /**
     * Returns the digest of the data added and resets the digest.
     * @return    the digest of all the data added to the message digest as a byte array.
     */
    public byte[] Digest(byte[] in)
    {
        byte b[] = java_digest(in, in.length);
        engineReset();
        return b;
    }

    private byte[] java_digest(byte[] in, int pos)
    {
        if (pos != 0) System.arraycopy(in, 0, tmp, 0, pos);

        tmp[pos++] = (byte)0x80;

        if (pos > DATA_LENGTH - 8)
        {
            while (pos < DATA_LENGTH)
                tmp[pos++] = 0;

            byte2int(tmp, 0, data, 0, DATA_LENGTH/4);
            transform(data);
            pos = 0;
        }

        while (pos < DATA_LENGTH - 8)
            tmp[pos++] = 0;

        byte2int(tmp, 0, data, 0, (DATA_LENGTH/4)-2);

        // Big endian
        // WARNING: int>>>32 != 0 !!!
        // bitcount() used to return a long, now it's an int.
        //long bc = bitcount();
	long bc = in.length * 8;
        data[14] = (int) (bc>>>32); 
        data[15] = (int) bc;

        transform(data);

        byte buf[] = new byte[HASH_LENGTH];

        // Big endian
        int off = 0;
        for (int i = 0; i < HASH_LENGTH/4; ++i) {
            int d = digest[i];
            buf[off++] = (byte) (d>>>24);
            buf[off++] = (byte) (d>>>16);
            buf[off++] = (byte) (d>>>8);
            buf[off++] = (byte)  d;
        }
        return buf;
    }


// SHA-1 transform routines
//...........................................................................

    private static int f1(int a, int b, int c) { return (c^(a&(b^c))) + 0x5A827999; }
    private static int f2(int a, int b, int c) { return (a^b^c) + 0x6ED9EBA1; }
    private static int f3(int a, int b, int c) { return ((a&b)|(c&(a|b))) + 0x8F1BBCDC; }
    private static int f4(int a, int b, int c) { return (a^b^c) + 0xCA62C1D6; }

    private void transform (int[] X)
    {
        int A = digest[0];
        int B = digest[1];
        int C = digest[2];
        int D = digest[3];
        int E = digest[4];

if (DEBUG) debug("A="+A+" B="+B+" C="+C+" D="+D+" E="+E);

        int W[] = w;
        for (int i=0; i<16; i++)
        {
            W[i] = X[i];
if (DEBUG) debug("       " + i + "=" + X[i]);
        }
        for (int i=16; i<80; i++)
        {
            int j = W[i-16] ^ W[i-14] ^ W[i-8] ^ W[i-3];
            W[i] = j;
            W[i] = (j << 1) | (j >>> -1);
        }

        E += ((A << 5)|(A >>> -5)) + f1(B, C, D) + W[0];  B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f1(A, B, C) + W[1];  A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f1(E, A, B) + W[2];  E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f1(D, E, A) + W[3];  D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f1(C, D, E) + W[4];  C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f1(B, C, D) + W[5];  B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f1(A, B, C) + W[6];  A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f1(E, A, B) + W[7];  E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f1(D, E, A) + W[8];  D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f1(C, D, E) + W[9];  C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f1(B, C, D) + W[10]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f1(A, B, C) + W[11]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f1(E, A, B) + W[12]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f1(D, E, A) + W[13]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f1(C, D, E) + W[14]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f1(B, C, D) + W[15]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f1(A, B, C) + W[16]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f1(E, A, B) + W[17]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f1(D, E, A) + W[18]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f1(C, D, E) + W[19]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f2(B, C, D) + W[20]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f2(A, B, C) + W[21]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f2(E, A, B) + W[22]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f2(D, E, A) + W[23]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f2(C, D, E) + W[24]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f2(B, C, D) + W[25]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f2(A, B, C) + W[26]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f2(E, A, B) + W[27]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f2(D, E, A) + W[28]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f2(C, D, E) + W[29]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f2(B, C, D) + W[30]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f2(A, B, C) + W[31]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f2(E, A, B) + W[32]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f2(D, E, A) + W[33]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f2(C, D, E) + W[34]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f2(B, C, D) + W[35]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f2(A, B, C) + W[36]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f2(E, A, B) + W[37]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f2(D, E, A) + W[38]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f2(C, D, E) + W[39]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f3(B, C, D) + W[40]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f3(A, B, C) + W[41]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f3(E, A, B) + W[42]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f3(D, E, A) + W[43]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f3(C, D, E) + W[44]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f3(B, C, D) + W[45]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f3(A, B, C) + W[46]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f3(E, A, B) + W[47]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f3(D, E, A) + W[48]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f3(C, D, E) + W[49]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f3(B, C, D) + W[50]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f3(A, B, C) + W[51]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f3(E, A, B) + W[52]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f3(D, E, A) + W[53]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f3(C, D, E) + W[54]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f3(B, C, D) + W[55]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f3(A, B, C) + W[56]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f3(E, A, B) + W[57]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f3(D, E, A) + W[58]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f3(C, D, E) + W[59]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f4(B, C, D) + W[60]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f4(A, B, C) + W[61]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f4(E, A, B) + W[62]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f4(D, E, A) + W[63]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f4(C, D, E) + W[64]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f4(B, C, D) + W[65]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f4(A, B, C) + W[66]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f4(E, A, B) + W[67]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f4(D, E, A) + W[68]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f4(C, D, E) + W[69]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f4(B, C, D) + W[70]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f4(A, B, C) + W[71]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f4(E, A, B) + W[72]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f4(D, E, A) + W[73]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f4(C, D, E) + W[74]; C =((C << 30)|(C >>> -30));
        E += ((A << 5)|(A >>> -5)) + f4(B, C, D) + W[75]; B =((B << 30)|(B >>> -30));
        D += ((E << 5)|(E >>> -5)) + f4(A, B, C) + W[76]; A =((A << 30)|(A >>> -30));
        C += ((D << 5)|(D >>> -5)) + f4(E, A, B) + W[77]; E =((E << 30)|(E >>> -30));
        B += ((C << 5)|(C >>> -5)) + f4(D, E, A) + W[78]; D =((D << 30)|(D >>> -30));
        A += ((B << 5)|(B >>> -5)) + f4(C, D, E) + W[79]; C =((C << 30)|(C >>> -30));

        digest[0] += A;
        digest[1] += B;
        digest[2] += C;
        digest[3] += D;
        digest[4] += E;
if (DEBUG) debug("d1="+digest[0]+" d1="+digest[1]+" d2="+digest[2]+" d3="+digest[3]+" d4="+digest[4]);
    }

    // why was this public?
    // Note: parameter order changed to be consistent with System.arraycopy.
    private static void byte2int(byte[] src, int srcOffset,
                                 int[] dst, int dstOffset, int length)
    {
        while (length-- > 0)
        {
            // Big endian
            dst[dstOffset++] = (src[srcOffset++]         << 24) |
                               ((src[srcOffset++] & 0xFF) << 16) |
                               ((src[srcOffset++] & 0xFF) <<  8) |
                                (src[srcOffset++] & 0xFF);
        }
    }


// // // // // // // // // // // //   T E S T   // // // // // // // //

/**
 * Entry point for <code>self_test</code>.
 */
public static final void
main(String argv[])
{
        try { self_test(); }
        catch(Throwable t) { t.printStackTrace(); System.exit(1);}
}

//
// Only two known sets of data!
// Using Hex format 0xAB results in needing casts.
//
private static String[] texts =
{
  "abc",                                                       // t 1
  "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",  // t 2
  "",                                                          // empty, added
}; 
private static byte[][] hashs =
{
  {-87,-103,62,54,71,6,-127,106,-70,62,37,113,120,80,-62,108,-100,-48,-40,-99,},
  {-124,-104,62,68,28,59,-46,110,-70,-82,74,-95,-7,81,41,-27,-27,70,112,-15,},
  {-38,57,-93,-18,94,107,75,13,50,85,-65,-17,-107,96,24,-112,-81,-40,7,9,},
}; 


/**
 * Do some basic tests.
 * Three of the known/validation data are included only, no output,
 * success or exception.
 * If you want more, write a test program!
 * @see cryptix.test.TestSHA1
 */     
public static final void
self_test()
throws Exception
{
    int length = hashs[0].length; 
    for (int i = 0; i < texts.length; i++)
    {
        SHA1 hash = new SHA1();
        byte[] text = texts[i].getBytes();
	byte [] hash1 = hash.Digest(text);
	debug("Computed: " + Hex.toString(hash1));
	debug("Known:    " + Hex.toString(hashs[i]));
        if (notEquals(hash1, hashs[i]))
            throw new MITCipherException("hash #"+ i +" failed");
    }       
}
            
private static final boolean
notEquals(byte[] a, byte[] b) 
{
    for (int i = 0; i < a.length; i++)
    {       
        if (a[i] != b[i])
            return true;
        // if (a[i] == -81) // force a trip up
        //     return true;
    }
    return false; 
}
}