<?php
/**
* jCryption
*
* PHP versions 4 and 5
*
* LICENSE: This source file is subject to version 3.0 of the PHP license
* that is available through the world-wide-web at the following URI:
* http://www.php.net/license/3_0.txt. If you did not receive a copy of
* the PHP License and are unable to obtain it through the web, please
* send a note to license@php.net so we can mail you a copy immediately.
*
* Many of the functions in this class are from the PEAR Crypt_RSA package ...
* So most of the credits goes to the original creator of this package Alexander Valyalkin
* you can get the package under http://pear.php.net/package/Crypt_RSA
*
* I just changed, added, removed and improved some functions to fit the needs of jCryption
*
* @author Daniel Griesser <daniel.griesser@jcryption.org>
* @copyright 2010 Daniel Griesser
* @license http://www.php.net/license/3_0.txt PHP License 3.0
* @version 1.1
* @link http://jcryption.org/
*/
class jCryption
{
public $_key_len;
public $_e;
/**
* Constructor
*
* @access public
*/
public function __construct($e = "\x01\x00\x01")
{
$this->_e = $e;
}
/**
* Generates the Keypair with the given keyLength the encryption key e ist set staticlly
* set to 65537 for faster encryption.
*
* @param int $keyLength
* @return array
* @access public
*/
public function generateKeypair($keyLength) {
$this->_key_len = intval($keyLength);
if ($this->_key_len < 8) {
$this->_key_len = 8;
}
// set [e] to 0x10001 (65537)
$e = $this->bin2int($this->_e);
// generate [p], [q] and [n]
$p_len = intval(($this->_key_len + 1) / 2);
$q_len = $this->_key_len - $p_len;
$p1 = $q1 = 0;
do {
// generate prime number [$p] with length [$p_len] with the following condition:
// GCD($e, $p - 1) = 1
do {
$p = $this->getPrime($p_len);
$p1 = $this->dec($p);
$tmp = $this->GCD($e, $p1);
} while (!$this->isOne($tmp));
// generate prime number [$q] with length [$q_len] with the following conditions:
// GCD($e, $q - 1) = 1
// $q != $p
do {
$q = $this->getPrime($q_len);
//$q = 102238965184417281201422828818276460200050705922822343263269460146519295919831;
$q1 = $this->dec($q);
$tmp = $this->GCD($e, $q1);
} while (!$this->isOne($tmp) && !$this->cmpAbs($q, $p));
// if (p < q), then exchange them
if ($this->cmpAbs($p, $q) < 0) {
$tmp = $p;
$p = $q;
$q = $tmp;
$tmp = $p1;
$p1 = $q1;
$q1 = $tmp;
}
// calculate n = p * q
$n = $this->mul($p, $q);
} while ($this->bitLen($n) != $this->_key_len);
// calculate d = 1/e mod (p - 1) * (q - 1)
$pq = $this->mul($p1, $q1);
$d = $this->invmod($e, $pq);
// store RSA keypair attributes
$keypair = array('n'=>$n, 'e'=>$e, 'd'=>$d, 'p'=>$p, 'q'=>$q);
return $keypair;
}
public function useKeys($keys,$keyLength) {
$this->_key_len = intval($keyLength);
if ($this->_key_len < 8) {
$this->_key_len = 8;
}
// set [e] to 0x10001 (65537)
$e = $this->bin2int($this->_e);
// generate [p], [q] and [n]
$p_len = intval(($this->_key_len + 1) / 2);
$q_len = $this->_key_len - $p_len;
$p1 = $q1 = 0;
do {
do {
$q = $keys[rand(0,count($keys))];
$p = $keys[rand(0,count($keys))];
$p1 = $this->dec($p);
$q1 = $this->dec($q);
} while (!$this->cmpAbs($q, $p));
// if (p < q), then exchange them
if ($this->cmpAbs($p, $q) < 0) {
$tmp = $p;
$p = $q;
$q = $tmp;
$tmp = $p1;
$p1 = $q1;
$q1 = $tmp;
}
// calculate n = p * q
$n = $this->mul($p, $q);
} while ($this->bitLen($n) != $this->_key_len);
// calculate d = 1/e mod (p - 1) * (q - 1)
$pq = $this->mul($p1, $q1);
$d = $this->invmod($e, $pq);
// store RSA keypair attributes
$keypair = array('n'=>$n, 'e'=>$e, 'd'=>$d, 'p'=>$p, 'q'=>$q);
return $keypair;
}
/**
* Finds greatest common divider (GCD) of $num1 and $num2
*
* @param string $num1
* @param string $num2
* @return string
* @access public
*/
public function GCD($num1, $num2) {
do {
$tmp = bcmod($num1, $num2);
$num1 = $num2;
$num2 = $tmp;
} while (bccomp($num2, '0'));
return $num1;
}
/**
* Performs Miller-Rabin primality test for number $num
* with base $base. Returns true, if $num is strong pseudoprime
* by base $base. Else returns false.
*
* @param string $num
* @param string $base
* @return bool
* @access private
*/
public function _millerTest($num, $base) {
if (!bccomp($num, '1')) {
// 1 is not prime ;)
return false;
}
$tmp = bcsub($num, '1');
$zero_bits = 0;
while (!bccomp(bcmod($tmp, '2'), '0')) {
$zero_bits++;
$tmp = bcdiv($tmp, '2');
}
$tmp = $this->powmod($base, $tmp, $num);
if (!bccomp($tmp, '1')) {
// $num is probably prime
return true;
}
while ($zero_bits--) {
if (!bccomp(bcadd($tmp, '1'), $num)) {
// $num is probably prime
return true;
}
$tmp = $this->powmod($tmp, '2', $num);
}
// $num is composite
return false;
}
/**
* Transforms binary representation of large integer into its native form.
*
* Example of transformation:
* $str = "\x12\x34\x56\x78\x90";
* $num = 0x9078563412;
*
* @param string $str
* @return string
* @access public
*/
public function bin2int($str) {
$result = '0';
$n = strlen($str);
do {
$result = bcadd(bcmul($result, '256'), ord($str {--$n} ));
} while ($n > 0);
return $result;
}
/**
* Transforms large integer into binary representation.
*
* Example of transformation:
* $num = 0x9078563412;
* $str = "\x12\x34\x56\x78\x90";
*
* @param string $num
* @return string
* @access public
*/
public function int2bin($num) {
$result = '';
do {
$result .= chr(bcmod($num, '256'));
$num = bcdiv($num, '256');
} while (bccomp($num, '0'));
return $result;
}
/**
* Calculates pow($num, $pow) (mod $mod)
*
* @param string $num
* @param string $pow
* @param string $mod
* @return string
* @access public
*/
public function powmod($num, $pow, $mod) {
if (function_exists('bcpowmod')) {
// bcpowmod is only available under PHP5
return bcpowmod($num, $pow, $mod);
}
// emulate bcpowmod
$result = '1';
do {
if (!bccomp(bcmod($pow, '2'), '1')) {
$result = bcmod(bcmul($result, $num), $mod);
}
$num = bcmod(bcpow($num, '2'), $mod);
$pow = bcdiv($pow, '2');
} while (bccomp($pow, '0'));
return $result;
}
/**
* Calculates $num1 * $num2
*
* @param string $num1
* @param string $num2
* @return string
* @access public
*/
public function mul($num1, $num2) {
return bcmul($num1, $num2);
}
/**
* Calculates $num1 % $num2
*
* @param string $num1
* @param string $num2
* @return string
* @access public
*/
public function mod($num1, $num2) {
return bcmod($num1, $num2);
}
/**
* Compares abs($num1) to abs($num2).
* Returns:
* -1, if abs($num1) < abs($num2)
* 0, if abs($num1) == abs($num2)
* 1, if abs($num1) > abs($num2)
*
* @param string $num1
* @param string $num2
* @return int
* @access public
*/
public function cmpAbs($num1, $num2) {
return bccomp($num1, $num2);
}
/**
* Tests $num on primality. Returns true, if $num is strong pseudoprime.
* Else returns false.
*
* @param string $num
* @return bool
* @access private
*/
public function isPrime($num) {
static $primes = null;
static $primes_cnt = 0;
if (is_null($primes)) {
// generate all primes up to 10000
$primes = [];
for ($i = 0; $i < 10000; $i++) {
$primes[] = $i;
}
$primes[0] = $primes[1] = 0;
for ($i = 2; $i < 100; $i++) {
while (!$primes[$i]) {
$i++;
}
$j = $i;
for ($j += $i; $j < 10000; $j += $i) {
$primes[$j] = 0;
}
}
$j = 0;
for ($i = 0; $i < 10000; $i++) {
if ($primes[$i]) {
$primes[$j++] = $primes[$i];
}
}
$primes_cnt = $j;
}
// try to divide number by small primes
for ($i = 0; $i < $primes_cnt; $i++) {
if (bccomp($num, $primes[$i]) <= 0) {
// number is prime
return true;
}
if (!bccomp(bcmod($num, $primes[$i]), '0')) {
// number divides by $primes[$i]
return false;
}
}
/*
try Miller-Rabin's probable-primality test for first
7 primes as bases
*/
for ($i = 0; $i < 7; $i++) {
if (!$this->_millerTest($num, $primes[$i])) {
// $num is composite
return false;
}
}
// $num is strong pseudoprime
return true;
}
/**
* Produces a better random number
* for seeding mt_rand()
*
* @access private
*/
public function _makeSeed() {
return hexdec(sha1(sha1(microtime(true)*mt_rand()).md5(microtime(true)*mt_rand())));
}
/**
* Generates prime number with length $bits_cnt
*
* @param int $bits_cnt
* @access public
*/
public function getPrime($bits_cnt) {
$bytes_n = intval($bits_cnt / 8);
$bits_n = $bits_cnt % 8;
do {
$str = '';
mt_srand((int)$this->_makeSeed());
for ($i = 0; $i < $bytes_n; $i++) {
$str .= chr((int)sha1(mt_rand() * microtime(true)) & 0xff);
}
$n = mt_rand() * microtime(true) & 0xff;
$n |= 0x80;
$n >>= 8 - $bits_n;
$str .= chr($n);
$num = $this->bin2int($str);
// search for the next closest prime number after [$num]
if (!bccomp(bcmod($num, '2'), '0')) {
$num = bcadd($num, '1');
}
while (!$this->isPrime($num)) {
$num = bcadd($num, '2');
}
} while ($this->bitLen($num) != $bits_cnt);
return $num;
}
/**
* Calculates $num - 1
*
* @param string $num
* @return string
* @access public
*/
public function dec($num) {
return bcsub($num, '1');
}
/**
* Returns true, if $num is equal to one. Else returns false
*
* @param string $num
* @return bool
* @access public
*/
public function isOne($num) {
return !bccomp($num, '1');
}
/**
* Finds inverse number $inv for $num by modulus $mod, such as:
* $inv * $num = 1 (mod $mod)
*
* @param string $num
* @param string $mod
* @return string
* @access public
*/
public function invmod($num, $mod) {
$x = '1';
$y = '0';
$num1 = $mod;
do {
$tmp = bcmod($num, $num1);
$q = bcdiv($num, $num1);
$num = $num1;
$num1 = $tmp;
$tmp = bcsub($x, bcmul($y, $q));
$x = $y;
$y = $tmp;
} while (bccomp($num1, '0'));
if (bccomp($x, '0') < 0) {
$x = bcadd($x, $mod);
}
return $x;
}
/**
* Returns bit length of number $num
*
* @param string $num
* @return int
* @access public
*/
public function bitLen($num) {
$tmp = $this->int2bin($num);
$bit_len = strlen($tmp) * 8;
$tmp = ord($tmp {strlen($tmp) - 1} );
if (!$tmp) {
$bit_len -= 8;
} else {
while (!($tmp & 0x80)) {
$bit_len--;
$tmp <<= 1;
}
}
return $bit_len;
}
/**
* Calculates bitwise or of $num1 and $num2,
* starting from bit $start_pos for number $num1
*
* @param string $num1
* @param string $num2
* @param int $start_pos
* @return string
* @access public
*/
public function bitOr($num1, $num2, $start_pos) {
$start_byte = intval($start_pos / 8);
$start_bit = $start_pos % 8;
$tmp1 = $this->int2bin($num1);
$num2 = bcmul($num2, 1 << $start_bit);
$tmp2 = $this->int2bin($num2);
if ($start_byte < strlen($tmp1)) {
$tmp2 |= substr($tmp1, $start_byte);
$tmp1 = substr($tmp1, 0, $start_byte).$tmp2;
} else {
$tmp1 = str_pad($tmp1, $start_byte, "\0").$tmp2;
}
return $this->bin2int($tmp1);
}
/**
* Returns part of number $num, starting at bit
* position $start with length $length
*
* @param string $num
* @param int start
* @param int length
* @return string
* @access public
*/
public function subint($num, $start, $length) {
$start_byte = intval($start / 8);
$start_bit = $start % 8;
$byte_length = intval($length / 8);
$bit_length = $length % 8;
if ($bit_length) {
$byte_length++;
}
$num = bcdiv($num, 1 << $start_bit);
$tmp = substr($this->int2bin($num), $start_byte, $byte_length);
$tmp = str_pad($tmp, $byte_length, "\0");
$tmp = substr_replace($tmp, $tmp {$byte_length - 1} & chr(0xff >> (8 - $bit_length)), $byte_length - 1, 1);
return $this->bin2int($tmp);
}
/**
* Converts a hex string to bigint string
*
* @param string $hex
* @return string
* @access public
*/
public function hex2bint($hex) {
$result = '0';
for ($i = 0; $i < strlen($hex); $i++) {
$result = bcmul($result, '16');
if ($hex[$i] >= '0' && $hex[$i] <= '9') {
$result = bcadd($result, $hex[$i]);
} else if ($hex[$i] >= 'a' && $hex[$i] <= 'f') {
$result = bcadd($result, '1'.('0' + (ord($hex[$i]) - ord('a'))));
} else if ($hex[$i] >= 'A' && $hex[$i] <= 'F') {
$result = bcadd($result, '1'.('0' + (ord($hex[$i]) - ord('A'))));
}
}
return $result;
}
/**
* Converts a hex string to int
*
* @param string $hex
* @return int
* @access public
*/
public function hex2int($hex) {
$result = 0;
for ($i = 0; $i < strlen($hex); $i++) {
$result *= 16;
if ($hex[$i] >= '0' && $hex[$i] <= '9') {
$result += ord($hex[$i]) - ord('0');
} else if ($hex[$i] >= 'a' && $hex[$i] <= 'f') {
$result += 10 + (ord($hex[$i]) - ord('a'));
} else if ($hex[$i] >= 'A' && $hex[$i] <= 'F') {
$result += 10 + (ord($hex[$i]) - ord('A'));
}
}
return $result;
}
/**
* Converts a bigint string to the ascii code
*
* @param string $bigint
* @return string
* @access public
*/
public function bint2char($bigint) {
$message = '';
while (bccomp($bigint, '0') != 0) {
$ascii = bcmod($bigint, '256');
$bigint = bcdiv($bigint, '256', 0);
$message .= chr($ascii);
}
return $message;
}
/**
* Removes the redundacy in den encrypted string
*
* @param string $string
* @return mixed
* @access public
*/
public function redundacyCheck($string) {
$r1 = substr($string, 0, 2);
$r2 = substr($string, 2);
$check = $this->hex2int($r1);
$value = $r2;
$sum = 0;
for ($i = 0; $i < strlen($value); $i++) {
$sum += ord($value[$i]);
}
if ($check == ($sum & 0xFF)) {
return $value;
} else {
return NULL;
}
}
/**
* Decrypts a given string with the $dec_key and the $enc_mod
*
* @param string $encrypted
* @param int $dec_key
* @param int $enc_mod
* @return string
* @access public
*/
public function decrypt($encrypted, $dec_key, $enc_mod) {
//replaced split with explode
$blocks = explode(' ', $encrypted);
$result = "";
$max = count($blocks);
for ($i = 0; $i < $max; $i++) {
$dec = $this->hex2bint($blocks[$i]);
$dec = $this->powmod($dec, $dec_key, $enc_mod);
$ascii = $this->bint2char($dec);
$result .= $ascii;
}
return $this->redundacyCheck($result);
}
/**
* Converts a given decimal string to any base between 2 and 36
*
* @param string $decimal
* @param int $base
* @return string
*/
public function dec2string($decimal, $base) {
$string = null;
$base = (int) $base;
if ($base < 2 | $base > 36 | $base == 10) {
echo 'BASE must be in the range 2-9 or 11-36';
exit;
}
$charset = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
$charset = substr($charset, 0, $base);
do {
$remainder = bcmod($decimal, $base);
$char = substr($charset, $remainder, 1);
$string = "$char$string";
$decimal = bcdiv(bcsub($decimal, $remainder), $base);
} while ($decimal > 0);
return strtolower($string);
}
public function getE() {
return $this->_e;
}
public function generatePrime($length) {
$this->_key_len = intval($length);
if ($this->_key_len < 8) {
$this->_key_len = 8;
}
$e = $this->bin2int("\x01\x00\x01");
$p_len = intval(($this->_key_len + 1) / 2);
do {
$p = $this->getPrime($p_len);
$p1 = $this->dec($p);
$tmp = $this->GCD($e, $p1);
} while (!$this->isOne($tmp));
return $p;
}
}