tea_encryption.php

<?php

/**
 * @param int $n
 * @return string
 */
function saltGenerator($n = 5)
{
	$s = range(chr(1), chr(255));
	$r = ""; $c=count($s)-1;
	for($i=0;$i<$n;$i++) {
		$r.= $s[rand(0, $c)];
	}
	return $r;
}

/**
 * @param string $string
 * @param string $key
 * @param bool	 $binarySafe
 * @return string
 */
function teaEncrypt($string, $key, $binarySafe = true)
{
	$slen = strlen($string);
	$klen = strlen($key);
	$r = $newKey = "";
	$salt = saltGenerator();
	$cost = 1;
	for($i=$j=0;$i<$klen;$i++) {
		$newKey .= chr(ord($key[$i]) ^ ord($salt[$j++]));
		if ($j === 5) {
			$j = 0;
		}
	}
	for($i=$j=$k=0;$i<$slen;$i++) {
		$r .= chr(
			ord($string[$i]) ^ ord($newKey[$j++]) ^ ord($salt[$k++]) ^ ($i << $j) ^ ($k >> $j) ^
			($slen % $cost) ^ ($cost >> $j) ^ ($cost >> $i) ^ ($cost >> $k) ^
			($cost ^ ($slen % ($i + $j + $k + 1))) ^ (($cost << $i) % 2) ^ (($cost << $j) % 2) ^ 
			(($cost << $k) % 2) ^ (($cost * ($i+$j+$k)) % 3)
		);
		$cost++;
		if ($j === $klen) {
			$j = 0;
		}
		if ($k === 5) {
			$k = 0;
		}
	}
	$r .= $salt;
	if ($binarySafe) {
		return strrev(base64_encode($r));
	} else {
		return $r;
	}
}

/**
 * @param string $string
 * @param string $key
 * @param bool	 $binarySafe
 * @return string
 */
function teaDecrypt($string, $key, $binarySafe = true)
{
	if ($binarySafe) {
		$string = base64_decode(strrev($string));
	}
	$slen = strlen($string);
	$salt = substr($string, $slen - 5);
	$string = substr($string, 0, ($slen = $slen - 5));
	$klen = strlen($key);
	$newKey = $r = "";
	$cost = 1;
	for($i=$j=0;$i<$klen;$i++) {
		$newKey .= chr(ord($key[$i]) ^ ord($salt[$j++]));
		if ($j === 5) {
			$j = 0;
		}
	}
	for($i=$j=$k=0;$i<$slen;$i++) {
		$r .= chr(
			ord($string[$i]) ^ ord($newKey[$j++]) ^ ord($salt[$k++]) ^ ($i << $j) ^ ($k >> $j) ^
			($slen % $cost) ^ ($cost >> $j) ^ ($cost >> $i) ^ ($cost >> $k) ^
			($cost ^ ($slen % ($i + $j + $k + 1))) ^ (($cost << $i) % 2) ^ (($cost << $j) % 2) ^ 
			(($cost << $k) % 2) ^ (($cost * ($i+$j+$k)) % 3)
		);
		$cost++;
		if ($j === $klen) {
			$j = 0;
		}
		if ($k === 5) {
			$k = 0;
		}
	}
	return $r;
}