File: sha.php

<?php
if (!defined('SHA_Included')) {
define('SHA_Included', 1);
////////////////////////////////////////////////////////////////////////////
// SHA implementation  v1.0
// Based on the SHA algorithm as given in "Applied Cryptography"
// Code written by Chris Monson (chris@bouncingchairs.net)
// Most recent version available on http://bouncingchairs.net
// Licensed under the GNU LGPL (http://www.gnu.org/copyleft/lesser.html)
// April 11, 2000
// License changed (I'm an idiot) June 26, 2000
////////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////////
// USAGE:
//------------------------------------------------------------------------
//      
//      Simple text hash:
//      
//      $sha = new SHA;
//      $hasharray = $sha->hash_string( 'hash me!' );
//
//      This returns an array of 5 32-bit integers.
//      The SHA.hash_bytes function does the same thing, but requires
//      an array of bytes as input.  Note that the input values will be
//      truncated if they are larger than 8 bits.
//
//------------------------------------------------------------------------
//
//      There are also some hash to string conversion functions.  The
//      naming convention admittedly could be better, but it works :).
//
//      $sha->hash_to_string( $hasharray )
//      
//      Converts the hash array to an uppercase hex string.
//
//------------------------------------------------------------------------
//
//      Hashing very large blocks a piece at a time:
//
//      $sha = new SHA;
//      $sha->init();
//      while (blocks_to_process) {
//          $sha->update( next_byte_array )
//      }
//      $hasharray = $sha->finalize()
//      
////////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////////
// NOTES:
//      This is basically a rip off of SHAPerl.pm, which I also wrote.
//      I discovered, much to my chagrin, that PHP does not have even
//      the crappy 32-bit int support that Perl has, so I had to employ
//      some funny tricks in the code to get it to use all 32 bits.
//      One of the most obvious of these is using an 'add' method instead
//      of just adding numbers together.  Any numbers over 32 bits don't get
//      bit-truncated.  They get corralled, which is not what I wanted.
//      Another trick I had to employ was splitting large numeric constants
//      into two pieces.  Apparently, you can't specify 0xffffffff.  It gets
//      set to 0.  Everything up to 0x7fffffff works fine.  So, I used
//      some shifting and bitwise operators to get the needed constants.
//
//      A word on optimization: it isn't optimized.  My chief concern was
//      to get it working, and it is fast enough for my needs.  If, however,
//      you intend to try to brute force some hash values with this, either
//      it will need some serious optimizations done, or you should be
//      using one of the freely available C implementations.
//
////////////////////////////////////////////////////////////////////////////
class SHA {
    var $A, $B, $C, $D, $E; // result variables
    var $ta, $tb, $tc, $td, $te; // temp variables
    var $K0_19, $K20_39, $K40_59, $K60_79;

    var $buffer;
    var $buffsize;
    var $totalsize;

    function SHA () {
        $this->init();
    }

    function init () {
        // The long constants can't be used for some dumb reason.
	$this->A = 0x6745 << 16 | 0x2301;
	$this->B = 0xefcd << 16 | 0xab89;
	$this->C = 0x98ba << 16 | 0xdcfe;
	$this->D = 0x1032 << 16 | 0x5476;
	$this->E = 0xc3d2 << 16 | 0xe1f0;
	$this->ta = $this->A;
	$this->tb = $this->B;
	$this->tc = $this->C;
	$this->td = $this->D;
	$this->te = $this->E;
	$this->K0_19 = 0x5a82 << 16 | 0x7999;
	$this->K20_39 = 0x6ed9 << 16 | 0xeba1;
	$this->K40_59 = 0x8f1b << 16 | 0xbcdc;
	$this->K60_79 = 0xca62 << 16 | 0xc1d6;

        $this->buffer = array();
        $this->buffsize = 0;
        $this->totalsize = 0;
    }

    function bytes_to_words( $block ) {
        $nblk = array();
        for( $i=0; $i<16; ++$i) {
            $index = $i * 4;
            $nblk[$i] = 0;
            $nblk[$i] |= ($block[$index] & 0xff) << 24;
            $nblk[$i] |= ($block[$index+1] & 0xff) << 16;
            $nblk[$i] |= ($block[$index+2] & 0xff) << 8;
            $nblk[$i] |= ($block[$index+3] & 0xff);
        }
        return $nblk;
    }

    function pad_block( $block, $size ) {
        // Returns a block that is a multiple of 512 bits long
        $blksize = sizeof( $block );
        $bits = $size * 8;

        // Always pad with 0x80, then add as many zeros as necessary to
        // make the message 64 bits short of 512.  Then add the 64-bit size.
        $newblock = $block;
        $newblock[] = 0x80; // push 0x80 onto the end
        // Add the zeros
        while((sizeof($newblock) % 64) != 56) {
            $newblock[] = 0;
        }
        // Add the size
        for ($i=0; $i<8; ++$i) {
            $newblock[] = ($i<4) ? 0 : ($bits >> ((7-$i)*8)) & 0xff;
        }

        return $newblock;
    }

    function circ_shl( $num, $amt ) {
        $leftmask = 0xffff | (0xffff << 16);
        $leftmask <<= 32 - $amt;
        $rightmask = 0xffff | (0xffff << 16);
        $rightmask <<= $amt;
        $rightmask = ~$rightmask;

        $remains = $num & $leftmask;
        $remains >>= 32 - $amt;
        $remains &= $rightmask;

        $res = ($num << $amt) | $remains;

        return $res;
    }

    function f0_19( $x, $y, $z ) {
        return ($x & $y) | (~$x & $z);
    }

    function f20_39( $x, $y, $z ) {
        return ($x ^ $y ^ $z);
    }

    function f40_59( $x, $y, $z ) {
        return ($x & $y) | ($x & $z) | ($y & $z);
    }

    function f60_79( $x, $y, $z ) {
        return $this->f20_39( $x, $y, $z );
    }

    function expand_block( $block ) {
        $nblk = $block;
        for( $i=16; $i<80; ++$i ) {
            $nblk[$i] = $this->circ_shl(
                    $nblk[$i-3] ^ $nblk[$i-8] ^ $nblk[$i-14] ^ $nblk[$i-16], 1
                );
        }

        return $nblk;
    }

    function print_bytes( $bytes ) {
        $len = sizeof( $bytes );
        for( $i=0; $i<$len; ++$i) {
            $str[] = sprintf( "%02x", $bytes[$i] );
        }

        print( join( ", ", $str ) . "\n" );
    }

    function wordstr( $word ) {
        return sprintf( 
            "%04x%04x", ($word >> 16) & 0xffff, $word & 0xffff
            );
    }

    function print_words( $words ) {
        $len = sizeof( $words );
        for( $i=0; $i<$len; ++$i) {
            $str[] = $this->wordstr( $words[$i] );
        }
        
        print( join( ", ", $str ) . "\n" );
    }

    function hash_to_string( $hash ) {
        $len = sizeof( $hash );
        for ($i=0; $i<$len; ++$i) {
            $astr[] = $this->wordstr( $hash[$i] );
        }
        return join( "", $astr );
    }

    // Add simply adds two numbers.  It is provided for compatibility on
    // platforms that only support a 31 bit add (there are a few, apparently)
    function add( $a, $b ) {
        $ma = ($a >> 16) & 0xffff;
        $la = ($a) & 0xffff;
        $mb = ($b >> 16) & 0xffff;
        $lb = ($b) & 0xffff;

        $ls = $la + $lb;
        // Carry
        if ($ls > 0xffff) {
            $ma += 1;
            $ls &= 0xffff;
        }

        // MS add
        $ms = $ma + $mb;
        $ms &= 0xffff;

        // Works because the bitwise operators are 32 bit
        $result = ($ms << 16) | $ls;
        return $result;
    }

    function process_block( $blk ) {
        $blk = $this->expand_block( $blk );

        for( $i=0; $i<80; ++$i ) {
            $temp = $this->circ_shl( $this->ta, 5 );
            if ($i<20) {
                $f = $this->f0_19( $this->tb, $this->tc, $this->td );
                $k = $this->K0_19;
            }
            elseif ($i<40) {
                $f = $this->f20_39( $this->tb, $this->tc, $this->td );
                $k = $this->K20_39;
            }
            elseif ($i<60) {
                $f = $this->f40_59( $this->tb, $this->tc, $this->td );
                $k = $this->K40_59;
            }
            else {
                $f = $this->f60_79( $this->tb, $this->tc, $this->td );
                $k = $this->K60_79;
            }

            $temp = $this->add( $temp, $f );
            $temp = $this->add( $temp, $this->te );
            $temp = $this->add( $temp, $blk[$i] );
            $temp = $this->add( $temp, $k );

            $this->te = $this->td;
            $this->td = $this->tc;
            $this->tc = $this->circ_shl( $this->tb, 30 );
            $this->tb = $this->ta;
            $this->ta = $temp;
        }

        $this->A = $this->add( $this->A, $this->ta );
        $this->B = $this->add( $this->B, $this->tb );
        $this->C = $this->add( $this->C, $this->tc );
        $this->D = $this->add( $this->D, $this->td );
        $this->E = $this->add( $this->E, $this->te );
    }

    function update ( $bytes ) {
        $length = sizeof( $bytes );
        $index = 0;

        // Process each full block
        while (($length - $index) + $this->buffsize >= 64) {
            for( $i=$this->buffsize; $i<64; ++$i) {
                $this->buffer[$i] = $bytes[$index + $i - $this->buffsize];
            }
            $this->process_block( $this->bytes_to_words( $this->buffer ) );
            $index += 64;
            $this->buffsize = 0;
        }

        // Any remaining bytes that do not make up a full block need to be'
        // added into the buffer for the next update (or final)
        $remaining = $length - $index;
        for( $i=0; $i<$remaining; ++$i) {
            $this->buffer[$this->buffsize + $i] = $bytes[$index + $i];
        }
        $this->buffsize += $remaining;
        $this->totalsize += $length;
    }

    function final() {
        // Pad and process the buffer
        for( $i=0; $i<$this->buffsize; ++$i) {
            $last_block[$i] = $this->buffer[$i];
        }
        $this->buffsize = 0;
        // Pad the block
        $last_block = $this->pad_block( $last_block, $this->totalsize );
        // Process the last one (or two) block(s)
        $index = 0;
        $length = sizeof( $last_block );
        while( $index < $length )
        {
            $block = array();
            for( $i=0; $i<64; ++$i) {
                $block[$i] = $last_block[$i + $index];
            }
            $this->process_block( $this->bytes_to_words( $block ) );
            $index += 64;
        }

        $result[0] = $this->A;
        $result[1] = $this->B;
        $result[2] = $this->C;
        $result[3] = $this->D;
        $result[4] = $this->E;

        return $result;
    }

    function hash_bytes( $bytes ) {
        $this->init();
        $this->update( $bytes );
        return $this->final();
    }

    function hash_string( $str ) {
        $len = strlen( $str );
        for($i=0; $i<$len; ++$i) {
            $bytes[] = ord( $str[$i] ) & 0xff;
        }
        return $this->hash_bytes( $bytes );
    }
}

} // If Included
?>