shs.cpp

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// shs.cpp - modified by Wei Dai from Peter Gutmann's code

#include <memory.h>
#include "shs.h"
#include "misc.h"

/* The SHS f()-functions.  The f1 and f3 functions can be optimized to
   save one boolean operation each - thanks to Rich Schroeppel,
   [e-mail] for discovering this */

/*#define f1(x,y,z) ( ( x & y ) | ( ~x & z ) )          // Rounds  0-19 */
#define f1(x,y,z)   ( z ^ ( x & ( y ^ z ) ) )           /* Rounds  0-19 */
#define f2(x,y,z)   ( x ^ y ^ z )                       /* Rounds 20-39 */
/*#define f3(x,y,z) ( ( x & y ) | ( x & z ) | ( y & z ) )   // Rounds 40-59 */
#define f3(x,y,z)   ( ( x & y ) | ( z & ( x | y ) ) )   /* Rounds 40-59 */
#define f4(x,y,z)   ( x ^ y ^ z )                       /* Rounds 60-79 */

/* The SHS Mysterious Constants */

#define K1  0x5A827999L                                 /* Rounds  0-19 */
#define K2  0x6ED9EBA1L                                 /* Rounds 20-39 */
#define K3  0x8F1BBCDCL                                 /* Rounds 40-59 */
#define K4  0xCA62C1D6L                                 /* Rounds 60-79 */

/* SHS initial values */

#define h0init  0x67452301L
#define h1init  0xEFCDAB89L
#define h2init  0x98BADCFEL
#define h3init  0x10325476L
#define h4init  0xC3D2E1F0L

/* Note that it may be necessary to add parentheses to these macros if they
   are to be called with expressions as arguments */

/* 32-bit rotate left - kludged with shifts */

#define ROTL(n,X)  ( ( ( X ) << n ) | ( ( X ) >> ( 32 - n ) ) )

/* The initial expanding function.  The hash function is defined over an
   80-word expanded input array W, where the first 16 are copies of the input
   data, and the remaining 64 are defined by

        W[ i ] = W[ i - 16 ] ^ W[ i - 14 ] ^ W[ i - 8 ] ^ W[ i - 3 ]

   This implementation generates these values on the fly in a circular
   buffer - thanks to Colin Plumb, [e-mail] for this
   optimization.

   The updated SHS changes the expanding function by adding a rotate of 1
   bit.  Thanks to Jim Gillogly, [e-mail], and an anonymous contributor
   for this information */

#ifdef NEW_SHS
  #define expand(W,i) ( W[ i & 15 ] = ROTL( 1, ( W[ i & 15 ] ^ W[ i - 14 & 15 ] ^ \
                                                 W[ i - 8 & 15 ] ^ W[ i - 3 & 15 ] ) ) )
#else
  #define expand(W,i) ( W[ i & 15 ] ^= W[ i - 14 & 15 ] ^ W[ i - 8 & 15 ] ^ W[ i - 3 & 15 ] )
#endif /* NEW_SHS */

/* The prototype SHS sub-round.  The fundamental sub-round is:

        a' = e + ROTL( 5, a ) + f( b, c, d ) + k + data;
        b' = a;
        c' = ROTL( 30, b );
        d' = c;
        e' = d;

   but this is implemented by unrolling the loop 5 times and renaming the
   variables ( e, a, b, c, d ) = ( a', b', c', d', e' ) each iteration.
   This code is then replicated 20 times for each of the 4 functions, using
   the next 20 values from the W[] array each time */

#define subRound(a, b, c, d, e, f, k, data) \
    ( e += ROTL( 5, a ) + f( b, c, d ) + k + data, b = ROTL( 30, b ) )

/* Initialize the SHS values */

SHS::SHS()
    : buffer(DIGESTSIZE/4 + DATASIZE/4),
      digest(buffer), data(digest+DIGESTSIZE/4)
{
    Init();
}

void SHS::Init()
{
    /* Set the h-vars to their initial values */
    digest[ 0 ] = h0init;
    digest[ 1 ] = h1init;
    digest[ 2 ] = h2init;
    digest[ 3 ] = h3init;
    digest[ 4 ] = h4init;

    /* Initialise bit count */
    countLo = countHi = 0;
}

/* Perform the SHS transformation.  Note that this code, like MD5, seems to
   break some optimizing compilers due to the complexity of the expressions
   and the size of the basic block.  It may be necessary to split it into
   sections, e.g. based on the four subrounds

   Note that this corrupts the data area */

void SHS::Transform( word32 *digest, const word32 *data )
{
    word32 eData[16];
    memcpy( eData, data, DATASIZE );

    register word32 A, B, C, D, E;
    A = digest[0];
    B = digest[1];
    C = digest[2];
    D = digest[3];
    E = digest[4];

    // Heavy mangling, in 4 sub-rounds of 20 interations each.
    subRound( A, B, C, D, E, f1, K1, eData[  0 ] );
    subRound( E, A, B, C, D, f1, K1, eData[  1 ] );
    subRound( D, E, A, B, C, f1, K1, eData[  2 ] );
    subRound( C, D, E, A, B, f1, K1, eData[  3 ] );
    subRound( B, C, D, E, A, f1, K1, eData[  4 ] );
    subRound( A, B, C, D, E, f1, K1, eData[  5 ] );
    subRound( E, A, B, C, D, f1, K1, eData[  6 ] );
    subRound( D, E, A, B, C, f1, K1, eData[  7 ] );
    subRound( C, D, E, A, B, f1, K1, eData[  8 ] );
    subRound( B, C, D, E, A, f1, K1, eData[  9 ] );
    subRound( A, B, C, D, E, f1, K1, eData[ 10 ] );
    subRound( E, A, B, C, D, f1, K1, eData[ 11 ] );
    subRound( D, E, A, B, C, f1, K1, eData[ 12 ] );
    subRound( C, D, E, A, B, f1, K1, eData[ 13 ] );
    subRound( B, C, D, E, A, f1, K1, eData[ 14 ] );
    subRound( A, B, C, D, E, f1, K1, eData[ 15 ] );
    subRound( E, A, B, C, D, f1, K1, expand( eData, 16 ) );
    subRound( D, E, A, B, C, f1, K1, expand( eData, 17 ) );
    subRound( C, D, E, A, B, f1, K1, expand( eData, 18 ) );
    subRound( B, C, D, E, A, f1, K1, expand( eData, 19 ) );

    subRound( A, B, C, D, E, f2, K2, expand( eData, 20 ) );
    subRound( E, A, B, C, D, f2, K2, expand( eData, 21 ) );
    subRound( D, E, A, B, C, f2, K2, expand( eData, 22 ) );
    subRound( C, D, E, A, B, f2, K2, expand( eData, 23 ) );
    subRound( B, C, D, E, A, f2, K2, expand( eData, 24 ) );
    subRound( A, B, C, D, E, f2, K2, expand( eData, 25 ) );
    subRound( E, A, B, C, D, f2, K2, expand( eData, 26 ) );
    subRound( D, E, A, B, C, f2, K2, expand( eData, 27 ) );
    subRound( C, D, E, A, B, f2, K2, expand( eData, 28 ) );
    subRound( B, C, D, E, A, f2, K2, expand( eData, 29 ) );
    subRound( A, B, C, D, E, f2, K2, expand( eData, 30 ) );
    subRound( E, A, B, C, D, f2, K2, expand( eData, 31 ) );
    subRound( D, E, A, B, C, f2, K2, expand( eData, 32 ) );
    subRound( C, D, E, A, B, f2, K2, expand( eData, 33 ) );
    subRound( B, C, D, E, A, f2, K2, expand( eData, 34 ) );
    subRound( A, B, C, D, E, f2, K2, expand( eData, 35 ) );
    subRound( E, A, B, C, D, f2, K2, expand( eData, 36 ) );
    subRound( D, E, A, B, C, f2, K2, expand( eData, 37 ) );
    subRound( C, D, E, A, B, f2, K2, expand( eData, 38 ) );
    subRound( B, C, D, E, A, f2, K2, expand( eData, 39 ) );

    subRound( A, B, C, D, E, f3, K3, expand( eData, 40 ) );
    subRound( E, A, B, C, D, f3, K3, expand( eData, 41 ) );
    subRound( D, E, A, B, C, f3, K3, expand( eData, 42 ) );
    subRound( C, D, E, A, B, f3, K3, expand( eData, 43 ) );
    subRound( B, C, D, E, A, f3, K3, expand( eData, 44 ) );
    subRound( A, B, C, D, E, f3, K3, expand( eData, 45 ) );
    subRound( E, A, B, C, D, f3, K3, expand( eData, 46 ) );
    subRound( D, E, A, B, C, f3, K3, expand( eData, 47 ) );
    subRound( C, D, E, A, B, f3, K3, expand( eData, 48 ) );
    subRound( B, C, D, E, A, f3, K3, expand( eData, 49 ) );
    subRound( A, B, C, D, E, f3, K3, expand( eData, 50 ) );
    subRound( E, A, B, C, D, f3, K3, expand( eData, 51 ) );
    subRound( D, E, A, B, C, f3, K3, expand( eData, 52 ) );
    subRound( C, D, E, A, B, f3, K3, expand( eData, 53 ) );
    subRound( B, C, D, E, A, f3, K3, expand( eData, 54 ) );
    subRound( A, B, C, D, E, f3, K3, expand( eData, 55 ) );
    subRound( E, A, B, C, D, f3, K3, expand( eData, 56 ) );
    subRound( D, E, A, B, C, f3, K3, expand( eData, 57 ) );
    subRound( C, D, E, A, B, f3, K3, expand( eData, 58 ) );
    subRound( B, C, D, E, A, f3, K3, expand( eData, 59 ) );

    subRound( A, B, C, D, E, f4, K4, expand( eData, 60 ) );
    subRound( E, A, B, C, D, f4, K4, expand( eData, 61 ) );
    subRound( D, E, A, B, C, f4, K4, expand( eData, 62 ) );
    subRound( C, D, E, A, B, f4, K4, expand( eData, 63 ) );
    subRound( B, C, D, E, A, f4, K4, expand( eData, 64 ) );
    subRound( A, B, C, D, E, f4, K4, expand( eData, 65 ) );
    subRound( E, A, B, C, D, f4, K4, expand( eData, 66 ) );
    subRound( D, E, A, B, C, f4, K4, expand( eData, 67 ) );
    subRound( C, D, E, A, B, f4, K4, expand( eData, 68 ) );
    subRound( B, C, D, E, A, f4, K4, expand( eData, 69 ) );
    subRound( A, B, C, D, E, f4, K4, expand( eData, 70 ) );
    subRound( E, A, B, C, D, f4, K4, expand( eData, 71 ) );
    subRound( D, E, A, B, C, f4, K4, expand( eData, 72 ) );
    subRound( C, D, E, A, B, f4, K4, expand( eData, 73 ) );
    subRound( B, C, D, E, A, f4, K4, expand( eData, 74 ) );
    subRound( A, B, C, D, E, f4, K4, expand( eData, 75 ) );
    subRound( E, A, B, C, D, f4, K4, expand( eData, 76 ) );
    subRound( D, E, A, B, C, f4, K4, expand( eData, 77 ) );
    subRound( C, D, E, A, B, f4, K4, expand( eData, 78 ) );
    subRound( B, C, D, E, A, f4, K4, expand( eData, 79 ) );

    digest[0] += A;
    digest[1] += B;
    digest[2] += C;
    digest[3] += D;
    digest[4] += E;

    memset(eData, 0, DATASIZE);
}

inline void SHS::do_block (const word32 *input)
{
#ifndef LITTLE_ENDIAN
    Transform(digest, input);
#else
    byteReverse(data, input, DATASIZE);
    Transform(digest, data);
#endif
}

/* Update SHS for a block of data */

void SHS::Update (const byte *input, unsigned int len)
{
    word32 tmp = countLo;
    if ((countLo = tmp + ((word32)len << 3)) < tmp)
        countHi++;             /* Carry from low to high */
    countHi += len >> 29;

    int num = ((int)tmp >> 3) & 0x3F;

    if (num != 0)
    {
        if ((num+len) >= DATASIZE)
		{
            memcpy((byte *)data+num, input, DATASIZE-num);
			do_block(data);
            input += (DATASIZE-num);
			len-=(DATASIZE - num);
			num=0;
			// drop through and do the rest
		}
		else
		{
            memcpy((byte *)data+num, input, len);
			return;
		}
	}

	// we now can process the input data in blocks of DATASIZE
	// chars and save the leftovers to this->data.
    if (len >= DATASIZE)
    {
        if ((int)input&3)   // test for 32-bit word alignment
            do
            {   // copy input first if it's not aligned correctly
                memcpy(data, input, DATASIZE);
                do_block(data);
                input+=DATASIZE;
                len-=DATASIZE;
            } while (len >= DATASIZE);
        else
            do
            {
                do_block((word32 *)input);
                input+=DATASIZE;
                len-=DATASIZE;
            } while (len >= DATASIZE);
    }

    memcpy(data, input, len);
}

/* Final wrapup - pad to DATASIZE-byte boundary with the bit pattern
   1 0* (64-bit count of bits processed, MSB-first) */

void SHS::Final(byte *hash)
{
    int count;
    byte *dataPtr;

    /* Compute number of bytes mod 64 */
    count = ( int ) countLo;
    count = ( count >> 3 ) & 0x3F;

    /* Set the first char of padding to 0x80.  This is safe since there is
       always at least one byte free */
    dataPtr = ( byte * ) data + count;
    *dataPtr++ = 0x80;

    /* Bytes of padding needed to make 64 bytes */
    count = DATASIZE - 1 - count;

    /* Pad out to 56 mod 64 */
    if( count < 8 )
    {
        /* Two lots of padding:  Pad the first block to 64 bytes */
        memset( dataPtr, 0, count );
        do_block(data);

        /* Now fill the next block with 56 bytes */
        memset( data, 0, DATASIZE - 8 );
    }
    else
    {
        /* Pad block to 56 bytes */
        memset( dataPtr, 0, count - 8 );
        CorrectEndianess( data, data, DATASIZE - 8 );
    }

    /* Append length in bits and transform */
    data[14] = countHi;
    data[15] = countLo;

    Transform( digest, data );
    CorrectEndianess( digest, digest, DIGESTSIZE);
    memcpy(hash, digest, DIGESTSIZE);

    // reinit so that the object can be used again
    Init();
}