ASDFHash: Ascii hashing function

asdfhash.php

<?php
/*
 * @name: asdfhash.php
 * @author: morgan ``indrora'' gangwere <[email protected]>
 * 
 * @license 2clause BSD
 *
 * Copyright (c) 2012, morgan ``indrora'' gangwere
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met: 
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer. 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @description
 *  asdfhash: a simple (if not overly-simple) hashing algo for stuff.
 * This isn't anything secure. Don't trust it to your bank data 'n' 
 * stuff like that.
 *
 * Since some people like longer names, you can adjust the constant
 * ASDF_MAXLEN to suit your needs.
 *
 * If you feel SHA512 isn't adequate, try one of its cousins, like
 * Whirlpool or crc32 (just kidding, don't use crc32 for anything)
 *
 * This is as one-way as I can make it. If you can get source
 * content from the hash, you're probably working in infosec. I
 * would totally love to see how you did it (other than bruteforcing
 * the entire ASCII keyspace -- that's cheating!).
 *
 * Fair warning: this will, eventually, produce such fine works
 * as "penis", "sex", "fuck", etc. If you want, drop the following
 * from the $chars array:
 *
 *  a,s,f,w,p,i,c,k,u
 *
 *  This drastically reduces your keyspace, but it keeps it.. ehh...
 *  "cleaner"? I've seen worse come out of imgur's algorithm.
 */

define("ASDF_MAXLEN", 8);

/**
 * @name asdfhash
 * @param $content [mixed] content which will become part of the hash
 * @description A light hashing function which replicates values such
 * as those from Imgur and other popular sites.
 */
function asdfhash($content)
{
	$hash = array();
	// Our allowed characters (URL safe, please!)
	$chars = str_split("ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz01234567890");
	// Content digenst (pick a hash, any hash);
	$content_md = str_split(hash("sha512", $content, TRUE));
	// This essentially guarantees that we will have a string
	// which is ASDF_MAXLEN chars long.
	for($x =0;$x<ASDF_MAXLEN;$x++)
	{
		foreach($content_md as $b)
		{
			$ch = $chars[($x*ord($b)+$x) % sizeof($chars)];
			$hash[($x+ord($ch))%ASDF_MAXLEN] = $ch;
		}
	}
	return implode('',$hash);
}

?>