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<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
/**
* Pure-PHP PKCS#1 (v2.1) compliant implementation of RSA.
*
* PHP versions 4 and 5
*
* Here's an example of how to encrypt and decrypt text with this library:
* <code>
* <?php
* include('Crypt/RSA.php');
*
* $rsa = new Crypt_RSA();
* extract($rsa->createKey());
*
* $plaintext = 'terrafrost';
*
* $rsa->loadKey($privatekey);
* $ciphertext = $rsa->encrypt($plaintext);
*
* $rsa->loadKey($publickey);
* echo $rsa->decrypt($ciphertext);
* ?>
* </code>
*
* Here's an example of how to create signatures and verify signatures with this library:
* <code>
* <?php
* include('Crypt/RSA.php');
*
* $rsa = new Crypt_RSA();
* extract($rsa->createKey());
*
* $plaintext = 'terrafrost';
*
* $rsa->loadKey($privatekey);
* $signature = $rsa->sign($plaintext);
*
* $rsa->loadKey($publickey);
* echo $rsa->verify($plaintext, $signature) ? 'verified' : 'unverified';
* ?>
* </code>
*
* LICENSE: This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*
* @category Crypt
* @package Crypt_RSA
* @author Jim Wigginton <terrafrost@php.net>
* @copyright MMIX Jim Wigginton
* @license http://www.gnu.org/licenses/lgpl.txt
* @version $Id: RSA.php,v 1.15 2010/04/10 15:57:02 terrafrost Exp $
* @link http://phpseclib.sourceforge.net
*/
/**
* Include Math_BigInteger
*/
require_once('Math/BigInteger.php');
/**
* Include Crypt_Random
*/
require_once('Crypt/Random.php');
/**
* Include Crypt_Hash
*/
require_once('Crypt/Hash.php');
/**#@+
* @access public
* @see Crypt_RSA::encrypt()
* @see Crypt_RSA::decrypt()
*/
/**
* Use {@link http://en.wikipedia.org/wiki/Optimal_Asymmetric_Encryption_Padding Optimal Asymmetric Encryption Padding}
* (OAEP) for encryption / decryption.
*
* Uses sha1 by default.
*
* @see Crypt_RSA::setHash()
* @see Crypt_RSA::setMGFHash()
*/
define('CRYPT_RSA_ENCRYPTION_OAEP', 1);
/**
* Use PKCS#1 padding.
*
* Although CRYPT_RSA_ENCRYPTION_OAEP offers more security, including PKCS#1 padding is necessary for purposes of backwards
* compatability with protocols (like SSH-1) written before OAEP's introduction.
*/
define('CRYPT_RSA_ENCRYPTION_PKCS1', 2);
/**#@-*/
/**#@+
* @access public
* @see Crypt_RSA::sign()
* @see Crypt_RSA::verify()
* @see Crypt_RSA::setHash()
*/
/**
* Use the Probabilistic Signature Scheme for signing
*
* Uses sha1 by default.
*
* @see Crypt_RSA::setSaltLength()
* @see Crypt_RSA::setMGFHash()
*/
define('CRYPT_RSA_SIGNATURE_PSS', 1);
/**
* Use the PKCS#1 scheme by default.
*
* Although CRYPT_RSA_SIGNATURE_PSS offers more security, including PKCS#1 signing is necessary for purposes of backwards
* compatability with protocols (like SSH-2) written before PSS's introduction.
*/
define('CRYPT_RSA_SIGNATURE_PKCS1', 2);
/**#@-*/
/**#@+
* @access private
* @see Crypt_RSA::createKey()
*/
/**
* ASN1 Integer
*/
define('CRYPT_RSA_ASN1_INTEGER', 2);
/**
* ASN1 Sequence (with the constucted bit set)
*/
define('CRYPT_RSA_ASN1_SEQUENCE', 48);
/**#@-*/
/**#@+
* @access private
* @see Crypt_RSA::Crypt_RSA()
*/
/**
* To use the pure-PHP implementation
*/
define('CRYPT_RSA_MODE_INTERNAL', 1);
/**
* To use the OpenSSL library
*
* (if enabled; otherwise, the internal implementation will be used)
*/
define('CRYPT_RSA_MODE_OPENSSL', 2);
/**#@-*/
/**#@+
* @access public
* @see Crypt_RSA::createKey()
* @see Crypt_RSA::setPrivateKeyFormat()
*/
/**
* PKCS#1 formatted private key
*
* Used by OpenSSH
*/
define('CRYPT_RSA_PRIVATE_FORMAT_PKCS1', 0);
/**#@-*/
/**#@+
* @access public
* @see Crypt_RSA::createKey()
* @see Crypt_RSA::setPublicKeyFormat()
*/
/**
* Raw public key
*
* An array containing two Math_BigInteger objects.
*
* The exponent can be indexed with any of the following:
*
* 0, e, exponent, publicExponent
*
* The modulus can be indexed with any of the following:
*
* 1, n, modulo, modulus
*/
define('CRYPT_RSA_PUBLIC_FORMAT_RAW', 1);
/**
* PKCS#1 formatted public key
*/
define('CRYPT_RSA_PUBLIC_FORMAT_PKCS1', 2);
/**
* OpenSSH formatted public key
*
* Place in $HOME/.ssh/authorized_keys
*/
define('CRYPT_RSA_PUBLIC_FORMAT_OPENSSH', 3);
/**#@-*/
/**
* Pure-PHP PKCS#1 compliant implementation of RSA.
*
* @author Jim Wigginton <terrafrost@php.net>
* @version 0.1.0
* @access public
* @package Crypt_RSA
*/
class Crypt_RSA {
/**
* Precomputed Zero
*
* @var Array
* @access private
*/
var $zero;
/**
* Precomputed One
*
* @var Array
* @access private
*/
var $one;
/**
* Private Key Format
*
* @var Integer
* @access private
*/
var $privateKeyFormat = CRYPT_RSA_PRIVATE_FORMAT_PKCS1;
/**
* Public Key Format
*
* @var Integer
* @access public
*/
var $publicKeyFormat = CRYPT_RSA_PUBLIC_FORMAT_PKCS1;
/**
* Modulus (ie. n)
*
* @var Math_BigInteger
* @access private
*/
var $modulus;
/**
* Modulus length
*
* @var Math_BigInteger
* @access private
*/
var $k;
/**
* Exponent (ie. e or d)
*
* @var Math_BigInteger
* @access private
*/
var $exponent;
/**
* Primes for Chinese Remainder Theorem (ie. p and q)
*
* @var Array
* @access private
*/
var $primes;
/**
* Exponents for Chinese Remainder Theorem (ie. dP and dQ)
*
* @var Array
* @access private
*/
var $exponents;
/**
* Coefficients for Chinese Remainder Theorem (ie. qInv)
*
* @var Array
* @access private
*/
var $coefficients;
/**
* Hash name
*
* @var String
* @access private
*/
var $hashName;
/**
* Hash function
*
* @var Crypt_Hash
* @access private
*/
var $hash;
/**
* Length of hash function output
*
* @var Integer
* @access private
*/
var $hLen;
/**
* Length of salt
*
* @var Integer
* @access private
*/
var $sLen;
/**
* Hash function for the Mask Generation Function
*
* @var Crypt_Hash
* @access private
*/
var $mgfHash;
/**
* Length of MGF hash function output
*
* @var Integer
* @access private
*/
var $mgfHLen;
/**
* Encryption mode
*
* @var Integer
* @access private
*/
var $encryptionMode = CRYPT_RSA_ENCRYPTION_OAEP;
/**
* Signature mode
*
* @var Integer
* @access private
*/
var $signatureMode = CRYPT_RSA_SIGNATURE_PSS;
/**
* Public Exponent
*
* @var Mixed
* @access private
*/
var $publicExponent = false;
/**
* Password
*
* @var String
* @access private
*/
var $password = '';
/**
* The constructor
*
* If you want to make use of the openssl extension, you'll need to set the mode manually, yourself. The reason
* Crypt_RSA doesn't do it is because OpenSSL doesn't fail gracefully. openssl_pkey_new(), in particular, requires
* openssl.cnf be present somewhere and, unfortunately, the only real way to find out is too late.
*
* @return Crypt_RSA
* @access public
*/
function Crypt_RSA()
{
if ( !defined('CRYPT_RSA_MODE') ) {
switch (true) {
//case extension_loaded('openssl') && version_compare(PHP_VERSION, '4.2.0', '>='):
// define('CRYPT_RSA_MODE', CRYPT_RSA_MODE_OPENSSL);
// break;
default:
define('CRYPT_RSA_MODE', CRYPT_RSA_MODE_INTERNAL);
}
}
$this->zero = new Math_BigInteger();
$this->one = new Math_BigInteger(1);
$this->hash = new Crypt_Hash('sha1');
$this->hLen = $this->hash->getLength();
$this->hashName = 'sha1';
$this->mgfHash = new Crypt_Hash('sha1');
$this->mgfHLen = $this->mgfHash->getLength();
}
/**
* Create public / private key pair
*
* Returns an array with the following three elements:
* - 'privatekey': The private key.
* - 'publickey': The public key.
* - 'partialkey': A partially computed key (if the execution time exceeded $timeout).
* Will need to be passed back to Crypt_RSA::createKey() as the third parameter for further processing.
*
* @access public
* @param optional Integer $bits
* @param optional Integer $timeout
* @param optional Math_BigInteger $p
*/
function createKey($bits = 1024, $timeout = false, $partial = array())
{
if ( CRYPT_RSA_MODE == CRYPT_RSA_MODE_OPENSSL ) {
$rsa = openssl_pkey_new(array('private_key_bits' => $bits));
openssl_pkey_export($rsa, $privatekey);
$publickey = openssl_pkey_get_details($rsa);
$publickey = $publickey['key'];
if ($this->privateKeyFormat != CRYPT_RSA_PRIVATE_FORMAT_PKCS1) {
$privatekey = call_user_func_array(array($this, '_convertPrivateKey'), array_values($this->_parseKey($privatekey, CRYPT_RSA_PRIVATE_FORMAT_PKCS1)));
$publickey = call_user_func_array(array($this, '_convertPublicKey'), array_values($this->_parseKey($publickey, CRYPT_RSA_PUBLIC_FORMAT_PKCS1)));
}
return array(
'privatekey' => $privatekey,
'publickey' => $publickey,
'partialkey' => false
);
}
static $e;
if (!isset($e)) {
if (!defined('CRYPT_RSA_EXPONENT')) {
// http://en.wikipedia.org/wiki/65537_%28number%29
define('CRYPT_RSA_EXPONENT', '65537');
}
if (!defined('CRYPT_RSA_COMMENT')) {
define('CRYPT_RSA_COMMENT', 'phpseclib-generated-key');
}
// per <http://cseweb.ucsd.edu/~hovav/dist/survey.pdf#page=5>, this number ought not result in primes smaller
// than 256 bits.
if (!defined('CRYPT_RSA_SMALLEST_PRIME')) {
define('CRYPT_RSA_SMALLEST_PRIME', 4096);
}
$e = new Math_BigInteger(CRYPT_RSA_EXPONENT);
}
extract($this->_generateMinMax($bits));
$absoluteMin = $min;
$temp = $bits >> 1;
if ($temp > CRYPT_RSA_SMALLEST_PRIME) {
$num_primes = floor($bits / CRYPT_RSA_SMALLEST_PRIME);
$temp = CRYPT_RSA_SMALLEST_PRIME;
} else {
$num_primes = 2;
}
extract($this->_generateMinMax($temp + $bits % $temp));
$finalMax = $max;
extract($this->_generateMinMax($temp));
$generator = new Math_BigInteger();
$generator->setRandomGenerator('crypt_random');
$n = $this->one->copy();
if (!empty($partial)) {
extract(unserialize($partial));
} else {
$exponents = $coefficients = $primes = array();
$lcm = array(
'top' => $this->one->copy(),
'bottom' => false
);
}
$start = time();
$i0 = count($primes) + 1;
do {
for ($i = $i0; $i <= $num_primes; $i++) {
if ($timeout !== false) {
$timeout-= time() - $start;
$start = time();
if ($timeout <= 0) {
return serialize(array(
'privatekey' => '',
'publickey' => '',
'partialkey' => array(
'primes' => $primes,
'coefficients' => $coefficients,
'lcm' => $lcm,
'exponents' => $exponents
)
));
}
}
if ($i == $num_primes) {
list($min, $temp) = $absoluteMin->divide($n);
if (!$temp->equals($this->zero)) {
$min = $min->add($this->one); // ie. ceil()
}
$primes[$i] = $generator->randomPrime($min, $finalMax, $timeout);
} else {
$primes[$i] = $generator->randomPrime($min, $max, $timeout);
}
if ($primes[$i] === false) { // if we've reached the timeout
return array(
'privatekey' => '',
'publickey' => '',
'partialkey' => empty($primes) ? '' : serialize(array(
'primes' => array_slice($primes, 0, $i - 1),
'coefficients' => $coefficients,
'lcm' => $lcm,
'exponents' => $exponents
))
);
}
// the first coefficient is calculated differently from the rest
// ie. instead of being $primes[1]->modInverse($primes[2]), it's $primes[2]->modInverse($primes[1])
if ($i > 2) {
$coefficients[$i] = $n->modInverse($primes[$i]);
}
$n = $n->multiply($primes[$i]);
$temp = $primes[$i]->subtract($this->one);
// textbook RSA implementations use Euler's totient function instead of the least common multiple.
// see http://en.wikipedia.org/wiki/Euler%27s_totient_function
$lcm['top'] = $lcm['top']->multiply($temp);
$lcm['bottom'] = $lcm['bottom'] === false ? $temp : $lcm['bottom']->gcd($temp);
$exponents[$i] = $e->modInverse($temp);
}
list($lcm) = $lcm['top']->divide($lcm['bottom']);
$gcd = $lcm->gcd($e);
$i0 = 1;
} while (!$gcd->equals($this->one));
$d = $e->modInverse($lcm);
$coefficients[2] = $primes[2]->modInverse($primes[1]);
// from <http://tools.ietf.org/html/rfc3447#appendix-A.1.2>:
// RSAPrivateKey ::= SEQUENCE {
// version Version,
// modulus INTEGER, -- n
// publicExponent INTEGER, -- e
// privateExponent INTEGER, -- d
// prime1 INTEGER, -- p
// prime2 INTEGER, -- q
// exponent1 INTEGER, -- d mod (p-1)
// exponent2 INTEGER, -- d mod (q-1)
// coefficient INTEGER, -- (inverse of q) mod p
// otherPrimeInfos OtherPrimeInfos OPTIONAL
// }
return array(
'privatekey' => $this->_convertPrivateKey($n, $e, $d, $primes, $exponents, $coefficients),
'publickey' => $this->_convertPublicKey($n, $e),
'partialkey' => false
);
}
/**
* Convert a private key to the appropriate format.
*
* @access private
* @see setPrivateKeyFormat()
* @param String $RSAPrivateKey
* @return String
*/
function _convertPrivateKey($n, $e, $d, $primes, $exponents, $coefficients)
{
$num_primes = count($primes);
$raw = array(
'version' => $num_primes == 2 ? chr(0) : chr(1), // two-prime vs. multi
'modulus' => $n->toBytes(true),
'publicExponent' => $e->toBytes(true),
'privateExponent' => $d->toBytes(true),
'prime1' => $primes[1]->toBytes(true),
'prime2' => $primes[2]->toBytes(true),
'exponent1' => $exponents[1]->toBytes(true),
'exponent2' => $exponents[2]->toBytes(true),
'coefficient' => $coefficients[2]->toBytes(true)
);
// if the format in question does not support multi-prime rsa and multi-prime rsa was used,
// call _convertPublicKey() instead.
switch ($this->privateKeyFormat) {
default: // eg. CRYPT_RSA_PRIVATE_FORMAT_PKCS1
$components = array();
foreach ($raw as $name => $value) {
$components[$name] = pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($value)), $value);
}
$RSAPrivateKey = implode('', $components);
if ($num_primes > 2) {
$OtherPrimeInfos = '';
for ($i = 3; $i <= $num_primes; $i++) {
// OtherPrimeInfos ::= SEQUENCE SIZE(1..MAX) OF OtherPrimeInfo
//
// OtherPrimeInfo ::= SEQUENCE {
// prime INTEGER, -- ri
// exponent INTEGER, -- di
// coefficient INTEGER -- ti
// }
$OtherPrimeInfo = pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($primes[$i]->toBytes(true))), $primes[$i]->toBytes(true));
$OtherPrimeInfo.= pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($exponents[$i]->toBytes(true))), $exponents[$i]->toBytes(true));
$OtherPrimeInfo.= pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($coefficients[$i]->toBytes(true))), $coefficients[$i]->toBytes(true));
$OtherPrimeInfos.= pack('Ca*a*', CRYPT_RSA_ASN1_SEQUENCE, $this->_encodeLength(strlen($OtherPrimeInfo)), $OtherPrimeInfo);
}
$RSAPrivateKey.= pack('Ca*a*', CRYPT_RSA_ASN1_SEQUENCE, $this->_encodeLength(strlen($OtherPrimeInfos)), $OtherPrimeInfos);
}
$RSAPrivateKey = pack('Ca*a*', CRYPT_RSA_ASN1_SEQUENCE, $this->_encodeLength(strlen($RSAPrivateKey)), $RSAPrivateKey);
if (!empty($this->password)) {
$iv = $this->_random(8);
$symkey = pack('H*', md5($this->password . $iv)); // symkey is short for symmetric key
$symkey.= substr(pack('H*', md5($symkey . $this->password . $iv)), 0, 8);
if (!class_exists('Crypt_TripleDES')) {
require_once('Crypt/TripleDES.php');
}
$des = new Crypt_TripleDES();
$des->setKey($symkey);
$des->setIV($iv);
$iv = strtoupper(bin2hex($iv));
$RSAPrivateKey = "-----BEGIN RSA PRIVATE KEY-----\r\n" .
"Proc-Type: 4,ENCRYPTED\r\n" .
"DEK-Info: DES-EDE3-CBC,$iv\r\n" .
"\r\n" .
chunk_split(base64_encode($des->encrypt($RSAPrivateKey))) .
'-----END RSA PRIVATE KEY-----';
} else {
$RSAPrivateKey = "-----BEGIN RSA PRIVATE KEY-----\r\n" .
chunk_split(base64_encode($RSAPrivateKey)) .
'-----END RSA PRIVATE KEY-----';
}
return $RSAPrivateKey;
}
}
/**
* Convert a public key to the appropriate format
*
* @access private
* @see setPublicKeyFormat()
* @param String $RSAPrivateKey
* @return String
*/
function _convertPublicKey($n, $e)
{
$modulus = $n->toBytes(true);
$publicExponent = $e->toBytes(true);
switch ($this->publicKeyFormat) {
case CRYPT_RSA_PUBLIC_FORMAT_RAW:
return array('e' => $e->copy(), 'n' => $n->copy());
case CRYPT_RSA_PUBLIC_FORMAT_OPENSSH:
// from <http://tools.ietf.org/html/rfc4253#page-15>:
// string "ssh-rsa"
// mpint e
// mpint n
$RSAPublicKey = pack('Na*Na*Na*', strlen('ssh-rsa'), 'ssh-rsa', strlen($publicExponent), $publicExponent, strlen($modulus), $modulus);
$RSAPublicKey = 'ssh-rsa ' . base64_encode($RSAPublicKey) . ' ' . CRYPT_RSA_COMMENT;
return $RSAPublicKey;
default: // eg. CRYPT_RSA_PUBLIC_FORMAT_PKCS1
// from <http://tools.ietf.org/html/rfc3447#appendix-A.1.1>:
// RSAPublicKey ::= SEQUENCE {
// modulus INTEGER, -- n
// publicExponent INTEGER -- e
// }
$components = array(
'modulus' => pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($modulus)), $modulus),
'publicExponent' => pack('Ca*a*', CRYPT_RSA_ASN1_INTEGER, $this->_encodeLength(strlen($publicExponent)), $publicExponent)
);
$RSAPublicKey = pack('Ca*a*a*',
CRYPT_RSA_ASN1_SEQUENCE, $this->_encodeLength(strlen($components['modulus']) + strlen($components['publicExponent'])),
$components['modulus'], $components['publicExponent']
);
$RSAPublicKey = "-----BEGIN PUBLIC KEY-----\r\n" .
chunk_split(base64_encode($RSAPublicKey)) .
'-----END PUBLIC KEY-----';
return $RSAPublicKey;
}
}
/**
* Break a public or private key down into its constituant components
*
* @access private
* @see _convertPublicKey()
* @see _convertPrivateKey()
* @param String $key
* @param Integer $type
* @return Array
*/
function _parseKey($key, $type)
{
switch ($type) {
case CRYPT_RSA_PUBLIC_FORMAT_RAW:
if (!is_array($key)) {
return false;
}
$components = array();
switch (true) {
case isset($key['e']):
$components['publicExponent'] = $key['e']->copy();
break;
case isset($key['exponent']):
$components['publicExponent'] = $key['exponent']->copy();
break;
case isset($key['publicExponent']):
$components['publicExponent'] = $key['publicExponent']->copy();
break;
case isset($key[0]):
$components['publicExponent'] = $key[0]->copy();
}
switch (true) {
case isset($key['n']):
$components['modulus'] = $key['n']->copy();
break;
case isset($key['modulo']):
$components['modulus'] = $key['modulo']->copy();
break;
case isset($key['modulus']):
$components['modulus'] = $key['modulus']->copy();
break;
case isset($key[1]):
$components['modulus'] = $key[1]->copy();
}
return $components;
case CRYPT_RSA_PRIVATE_FORMAT_PKCS1:
case CRYPT_RSA_PUBLIC_FORMAT_PKCS1:
/* Although PKCS#1 proposes a format that public and private keys can use, encrypting them is
"outside the scope" of PKCS#1. PKCS#1 then refers you to PKCS#12 and PKCS#15 if you're wanting to
protect private keys, however, that's not what OpenSSL* does. OpenSSL protects private keys by adding
two new "fields" to the key - DEK-Info and Proc-Type. These fields are discussed here:
http://tools.ietf.org/html/rfc1421#section-4.6.1.1
http://tools.ietf.org/html/rfc1421#section-4.6.1.3
DES-EDE3-CBC as an algorithm, however, is not discussed anywhere, near as I can tell.
DES-CBC and DES-EDE are discussed in RFC1423, however, DES-EDE3-CBC isn't, nor is its key derivation
function. As is, the definitive authority on this encoding scheme isn't the IETF but rather OpenSSL's
own implementation. ie. the implementation *is* the standard and any bugs that may exist in that
implementation are part of the standard, as well.
* OpenSSL is the de facto standard. It's utilized by OpenSSH and other projects */
if (preg_match('#DEK-Info: (.+),(.+)#', $key, $matches)) {
$iv = pack('H*', trim($matches[2]));
$symkey = pack('H*', md5($this->password . $iv)); // symkey is short for symmetric key
$symkey.= substr(pack('H*', md5($symkey . $this->password . $iv)), 0, 8);
$ciphertext = preg_replace('#.+(\r|\n|\r\n)\1|[\r\n]|-.+-#s', '', $key);
$ciphertext = preg_match('#^[a-zA-Z\d/+]*={0,2}$#', $ciphertext) ? base64_decode($ciphertext) : false;
if ($ciphertext === false) {
$ciphertext = $key;
}
switch ($matches[1]) {
case 'DES-EDE3-CBC':
if (!class_exists('Crypt_TripleDES')) {
require_once('Crypt/TripleDES.php');
}
$crypto = new Crypt_TripleDES();
break;
case 'DES-CBC':
if (!class_exists('Crypt_DES')) {
require_once('Crypt/DES.php');
}
$crypto = new Crypt_DES();
break;
default:
return false;
}
$crypto->setKey($symkey);
$crypto->setIV($iv);
$decoded = $crypto->decrypt($ciphertext);
} else {
$decoded = preg_replace('#-.+-|[\r\n]#', '', $key);
$decoded = preg_match('#^[a-zA-Z\d/+]*={0,2}$#', $decoded) ? base64_decode($decoded) : false;
}
if ($decoded !== false) {
$key = $decoded;
}
$components = array();
if (ord($this->_string_shift($key)) != CRYPT_RSA_ASN1_SEQUENCE) {
return false;
}
if ($this->_decodeLength($key) != strlen($key)) {
return false;
}
$tag = ord($this->_string_shift($key));
if ($tag == CRYPT_RSA_ASN1_SEQUENCE) {
/* intended for keys for which OpenSSL's asn1parse returns the following:
0:d=0 hl=4 l= 290 cons: SEQUENCE
4:d=1 hl=2 l= 13 cons: SEQUENCE
6:d=2 hl=2 l= 9 prim: OBJECT :rsaEncryption
17:d=2 hl=2 l= 0 prim: NULL
19:d=1 hl=4 l= 271 prim: BIT STRING */
$this->_string_shift($key, $this->_decodeLength($key));
$this->_string_shift($key); // skip over the BIT STRING tag
$this->_decodeLength($key); // skip over the BIT STRING length
// "The initial octet shall encode, as an unsigned binary integer wtih bit 1 as the least significant bit, the number of
// unused bits in teh final subsequent octet. The number shall be in the range zero to seven."
// -- http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf (section 8.6.2.2)
$this->_string_shift($key);
if (ord($this->_string_shift($key)) != CRYPT_RSA_ASN1_SEQUENCE) {
return false;
}
if ($this->_decodeLength($key) != strlen($key)) {
return false;
}
$tag = ord($this->_string_shift($key));
}
if ($tag != CRYPT_RSA_ASN1_INTEGER) {
return false;
}
$length = $this->_decodeLength($key);
$temp = $this->_string_shift($key, $length);
if (strlen($temp) != 1 || ord($temp) > 2) {
$components['modulus'] = new Math_BigInteger($temp, -256);
$this->_string_shift($key); // skip over CRYPT_RSA_ASN1_INTEGER
$length = $this->_decodeLength($key);
$components[$type == CRYPT_RSA_PUBLIC_FORMAT_PKCS1 ? 'publicExponent' : 'privateExponent'] = new Math_BigInteger($this->_string_shift($key, $length), -256);
return $components;
}
if (ord($this->_string_shift($key)) != CRYPT_RSA_ASN1_INTEGER) {
return false;
}
$length = $this->_decodeLength($key);
$components['modulus'] = new Math_BigInteger($this->_string_shift($key, $length), -256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['publicExponent'] = new Math_BigInteger($this->_string_shift($key, $length), -256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['privateExponent'] = new Math_BigInteger($this->_string_shift($key, $length), -256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['primes'] = array(1 => new Math_BigInteger($this->_string_shift($key, $length), -256));
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['primes'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['exponents'] = array(1 => new Math_BigInteger($this->_string_shift($key, $length), -256));
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['exponents'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['coefficients'] = array(2 => new Math_BigInteger($this->_string_shift($key, $length), -256));
if (!empty($key)) {
if (ord($this->_string_shift($key)) != CRYPT_RSA_ASN1_SEQUENCE) {
return false;
}
$this->_decodeLength($key);
while (!empty($key)) {
if (ord($this->_string_shift($key)) != CRYPT_RSA_ASN1_SEQUENCE) {
return false;
}
$this->_decodeLength($key);
$key = substr($key, 1);
$length = $this->_decodeLength($key);
$components['primes'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['exponents'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);
$this->_string_shift($key);
$length = $this->_decodeLength($key);
$components['coefficients'][] = new Math_BigInteger($this->_string_shift($key, $length), -256);
}
}
return $components;
case CRYPT_RSA_PUBLIC_FORMAT_OPENSSH:
$key = base64_decode(preg_replace('#^ssh-rsa | .+$#', '', $key));
if ($key === false) {
return false;
}
$cleanup = substr($key, 0, 11) == "\0\0\0\7ssh-rsa";
extract(unpack('Nlength', $this->_string_shift($key, 4)));
$publicExponent = new Math_BigInteger($this->_string_shift($key, $length), -256);
extract(unpack('Nlength', $this->_string_shift($key, 4)));
$modulus = new Math_BigInteger($this->_string_shift($key, $length), -256);
if ($cleanup && strlen($key)) {
extract(unpack('Nlength', $this->_string_shift($key, 4)));
return array(
'modulus' => new Math_BigInteger($this->_string_shift($key, $length), -256),
'publicExponent' => $modulus
);
} else {
return array(
'modulus' => $modulus,
'publicExponent' => $publicExponent
);
}
}
}
/**
* Loads a public or private key
*
* Returns true on success and false on failure (ie. an incorrect password was provided or the key was malformed)
*
* @access public
* @param String $key
* @param Integer $type optional
*/
function loadKey($key, $type = CRYPT_RSA_PRIVATE_FORMAT_PKCS1)
{
$components = $this->_parseKey($key, $type);
if ($components === false) {
return false;
}
$this->modulus = $components['modulus'];
$this->k = strlen($this->modulus->toBytes());
$this->exponent = isset($components['privateExponent']) ? $components['privateExponent'] : $components['publicExponent'];
if (isset($components['primes'])) {
$this->primes = $components['primes'];
$this->exponents = $components['exponents'];
$this->coefficients = $components['coefficients'];
$this->publicExponent = $components['publicExponent'];
} else {
$this->primes = array();
$this->exponents = array();
$this->coefficients = array();
$this->publicExponent = false;
}
return true;
}
/**
* Sets the password
*
* Private keys can be encrypted with a password. To unset the password, pass in the empty string or false.
* Or rather, pass in $password such that empty($password) is true.
*
* @see createKey()
* @see loadKey()
* @access public
* @param String $password
*/
function setPassword($password)
{
$this->password = $password;
}
/**
* Defines the public key
*
* Some private key formats define the public exponent and some don't. Those that don't define it are problematic when
* used in certain contexts. For example, in SSH-2, RSA authentication works by sending the public key along with a
* message signed by the private key to the server. The SSH-2 server looks the public key up in an index of public keys
* and if it's present then proceeds to verify the signature. Problem is, if your private key doesn't include the public
* exponent this won't work unless you manually add the public exponent.
*
* Do note that when a new key is loaded the index will be cleared.
*
* Returns true on success, false on failure
*
* @see getPublicKey()
* @access public
* @param String $key
* @param Integer $type optional
* @return Boolean
*/
function setPublicKey($key, $type = CRYPT_RSA_PUBLIC_FORMAT_PKCS1)
{
$components = $this->_parseKey($key, $type);
if (empty($this->modulus) || !$this->modulus->equals($components['modulus'])) {
return false;
}
$this->publicExponent = $components['publicExponent'];
}
/**
* Returns the public key
*
* The public key is only returned under two circumstances - if the private key had the public key embedded within it
* or if the public key was set via setPublicKey(). If the currently loaded key is supposed to be the public key this
* function won't return it since this library, for the most part, doesn't distinguish between public and private keys.
*
* @see getPublicKey()
* @access public
* @param String $key
* @param Integer $type optional
*/
function getPublicKey($type = CRYPT_RSA_PUBLIC_FORMAT_PKCS1)
{
if (empty($this->modulus) || empty($this->publicExponent)) {
return false;
}
$oldFormat = $this->publicKeyFormat;
$this->publicKeyFormat = $type;
$temp = $this->_convertPublicKey($this->modulus, $this->publicExponent);
$this->publicKeyFormat = $oldFormat;
return $temp;
}
/**
* Generates the smallest and largest numbers requiring $bits bits
*
* @access private
* @param Integer $bits
* @return Array
*/
function _generateMinMax($bits)
{
$bytes = $bits >> 3;
$min = str_repeat(chr(0), $bytes);
$max = str_repeat(chr(0xFF), $bytes);
$msb = $bits & 7;
if ($msb) {
$min = chr(1 << ($msb - 1)) . $min;
$max = chr((1 << $msb) - 1) . $max;
} else {
$min[0] = chr(0x80);
}
return array(
'min' => new Math_BigInteger($min, 256),
'max' => new Math_BigInteger($max, 256)
);
}
/**
* DER-decode the length
*
* DER supports lengths up to (2**8)**127, however, we'll only support lengths up to (2**8)**4. See
* {@link http://itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf#p=13 X.690 � 8.1.3} for more information.
*
* @access private
* @param String $string
* @return Integer
*/
function _decodeLength(&$string)
{
$length = ord($this->_string_shift($string));
if ( $length & 0x80 ) { // definite length, long form
$length&= 0x7F;
$temp = $this->_string_shift($string, $length);
list(, $length) = unpack('N', substr(str_pad($temp, 4, chr(0), STR_PAD_LEFT), -4));
}
return $length;
}
/**
* DER-encode the length
*
* DER supports lengths up to (2**8)**127, however, we'll only support lengths up to (2**8)**4. See
* {@link http://itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf#p=13 X.690 � 8.1.3} for more information.
*
* @access private
* @param Integer $length
* @return String
*/
function _encodeLength($length)
{
if ($length <= 0x7F) {
return chr($length);
}
$temp = ltrim(pack('N', $length), chr(0));
return pack('Ca*', 0x80 | strlen($temp), $temp);
}
/**
* String Shift
*
* Inspired by array_shift
*
* @param String $string
* @param optional Integer $index
* @return String
* @access private
*/
function _string_shift(&$string, $index = 1)
{
$substr = substr($string, 0, $index);
$string = substr($string, $index);
return $substr;
}
/**
* Determines the private key format
*
* @see createKey()
* @access public
* @param Integer $format
*/
function setPrivateKeyFormat($format)
{
$this->privateKeyFormat = $format;
}
/**
* Determines the public key format
*
* @see createKey()
* @access public
* @param Integer $format
*/
function setPublicKeyFormat($format)
{
$this->publicKeyFormat = $format;
}
/**
* Determines which hashing function should be used
*
* Used with signature production / verification and (if the encryption mode is CRYPT_RSA_ENCRYPTION_OAEP) encryption and
* decryption. If $hash isn't supported, sha1 is used.
*
* @access public
* @param String $hash
*/
function setHash($hash)
{
// Crypt_Hash supports algorithms that PKCS#1 doesn't support. md5-96 and sha1-96, for example.
switch ($hash) {
case 'md2':
case 'md5':
case 'sha1':
case 'sha256':
case 'sha384':
case 'sha512':
$this->hash = new Crypt_Hash($hash);
$this->hashName = $hash;
break;
default:
$this->hash = new Crypt_Hash('sha1');
$this->hashName = 'sha1';
}
$this->hLen = $this->hash->getLength();
}
/**
* Determines which hashing function should be used for the mask generation function
*
* The mask generation function is used by CRYPT_RSA_ENCRYPTION_OAEP and CRYPT_RSA_SIGNATURE_PSS and although it's
* best if Hash and MGFHash are set to the same thing this is not a requirement.
*
* @access public
* @param String $hash
*/
function setMGFHash($hash)
{
// Crypt_Hash supports algorithms that PKCS#1 doesn't support. md5-96 and sha1-96, for example.
switch ($hash) {
case 'md2':
case 'md5':
case 'sha1':
case 'sha256':
case 'sha384':
case 'sha512':
$this->mgfHash = new Crypt_Hash($hash);
break;
default:
$this->mgfHash = new Crypt_Hash('sha1');
}
$this->mgfHLen = $this->mgfHash->getLength();
}
/**
* Determines the salt length
*
* To quote from {@link http://tools.ietf.org/html/rfc3447#page-38 RFC3447#page-38}:
*
* Typical salt lengths in octets are hLen (the length of the output
* of the hash function Hash) and 0.
*
* @access public
* @param Integer $format
*/
function setSaltLength($sLen)
{
$this->sLen = $sLen;
}
/**
* Generates a random string x bytes long
*
* @access public
* @param Integer $bytes
* @param optional Integer $nonzero
* @return String
*/
function _random($bytes, $nonzero = false)
{
$temp = '';
if ($nonzero) {
for ($i = 0; $i < $bytes; $i++) {
$temp.= chr(crypt_random(1, 255));
}
} else {
$ints = ($bytes + 1) >> 2;
for ($i = 0; $i < $ints; $i++) {
$temp.= pack('N', crypt_random());
}
$temp = substr($temp, 0, $bytes);
}
return $temp;
}
/**
* Integer-to-Octet-String primitive
*
* See {@link http://tools.ietf.org/html/rfc3447#section-4.1 RFC3447#section-4.1}.
*
* @access private
* @param Math_BigInteger $x
* @param Integer $xLen
* @return String
*/
function _i2osp($x, $xLen)
{
$x = $x->toBytes();
if (strlen($x) > $xLen) {
user_error('Integer too large', E_USER_NOTICE);
return false;
}
return str_pad($x, $xLen, chr(0), STR_PAD_LEFT);
}
/**
* Octet-String-to-Integer primitive
*
* See {@link http://tools.ietf.org/html/rfc3447#section-4.2 RFC3447#section-4.2}.
*
* @access private
* @param String $x
* @return Math_BigInteger
*/
function _os2ip($x)
{
return new Math_BigInteger($x, 256);
}
/**
* Exponentiate with or without Chinese Remainder Theorem
*
* See {@link http://tools.ietf.org/html/rfc3447#section-5.1.1 RFC3447#section-5.1.2}.
*
* @access private
* @param Math_BigInteger $x
* @return Math_BigInteger
*/
function _exponentiate($x)
{
if (empty($this->primes) || empty($this->coefficients) || empty($this->exponents)) {
return $x->modPow($this->exponent, $this->modulus);
}
$num_primes = count($this->primes);
if (defined('CRYPT_RSA_DISABLE_BLINDING')) {
$m_i = array(
1 => $x->modPow($this->exponents[1], $this->primes[1]),
2 => $x->modPow($this->exponents[2], $this->primes[2])
);
$h = $m_i[1]->subtract($m_i[2]);
$h = $h->multiply($this->coefficients[2]);
list(, $h) = $h->divide($this->primes[1]);
$m = $m_i[2]->add($h->multiply($this->primes[2]));
$r = $this->primes[1];
for ($i = 3; $i <= $num_primes; $i++) {
$m_i = $x->modPow($this->exponents[$i], $this->primes[$i]);
$r = $r->multiply($this->primes[$i - 1]);
$h = $m_i->subtract($m);
$h = $h->multiply($this->coefficients[$i]);
list(, $h) = $h->divide($this->primes[$i]);
$m = $m->add($r->multiply($h));
}
} else {
$smallest = $this->primes[1];
for ($i = 2; $i <= $num_primes; $i++) {
if ($smallest->compare($this->primes[$i]) > 0) {
$smallest = $this->primes[$i];
}
}
$one = new Math_BigInteger(1);
$one->setRandomGenerator('crypt_random');
$r = $one->random($one, $smallest->subtract($one));
$m_i = array(
1 => $this->_blind($x, $r, 1),
2 => $this->_blind($x, $r, 2)
);
$h = $m_i[1]->subtract($m_i[2]);
$h = $h->multiply($this->coefficients[2]);
list(, $h) = $h->divide($this->primes[1]);
$m = $m_i[2]->add($h->multiply($this->primes[2]));
$r = $this->primes[1];
for ($i = 3; $i <= $num_primes; $i++) {
$m_i = $this->_blind($x, $r, $i);
$r = $r->multiply($this->primes[$i - 1]);
$h = $m_i->subtract($m);
$h = $h->multiply($this->coefficients[$i]);
list(, $h) = $h->divide($this->primes[$i]);
$m = $m->add($r->multiply($h));
}
}
return $m;
}
/**
* Performs RSA Blinding
*
* Protects against timing attacks by employing RSA Blinding.
* Returns $x->modPow($this->exponents[$i], $this->primes[$i])
*
* @access private
* @param Math_BigInteger $x
* @param Math_BigInteger $r
* @param Integer $i
* @return Math_BigInteger
*/
function _blind($x, $r, $i)
{
$x = $x->multiply($r->modPow($this->publicExponent, $this->primes[$i]));
$x = $x->modPow($this->exponents[$i], $this->primes[$i]);
$r = $r->modInverse($this->primes[$i]);
$x = $x->multiply($r);
list(, $x) = $x->divide($this->primes[$i]);
return $x;
}
/**
* RSAEP
*
* See {@link http://tools.ietf.org/html/rfc3447#section-5.1.1 RFC3447#section-5.1.1}.
*
* @access private
* @param Math_BigInteger $m
* @return Math_BigInteger
*/
function _rsaep($m)
{
if ($m->compare($this->zero) < 0 || $m->compare($this->modulus) > 0) {
user_error('Message representative out of range', E_USER_NOTICE);
return false;
}
return $this->_exponentiate($m);
}
/**
* RSADP
*
* See {@link http://tools.ietf.org/html/rfc3447#section-5.1.2 RFC3447#section-5.1.2}.
*
* @access private
* @param Math_BigInteger $c
* @return Math_BigInteger
*/
function _rsadp($c)
{
if ($c->compare($this->zero) < 0 || $c->compare($this->modulus) > 0) {
user_error('Ciphertext representative out of range', E_USER_NOTICE);
return false;
}
return $this->_exponentiate($c);
}
/**
* RSASP1
*
* See {@link http://tools.ietf.org/html/rfc3447#section-5.2.1 RFC3447#section-5.2.1}.
*
* @access private
* @param Math_BigInteger $m
* @return Math_BigInteger
*/
function _rsasp1($m)
{
if ($m->compare($this->zero) < 0 || $m->compare($this->modulus) > 0) {
user_error('Message representative out of range', E_USER_NOTICE);
return false;
}
return $this->_exponentiate($m);
}
/**
* RSAVP1
*
* See {@link http://tools.ietf.org/html/rfc3447#section-5.2.2 RFC3447#section-5.2.2}.
*
* @access private
* @param Math_BigInteger $s
* @return Math_BigInteger
*/
function _rsavp1($s)
{
if ($s->compare($this->zero) < 0 || $s->compare($this->modulus) > 0) {
user_error('Signature representative out of range', E_USER_NOTICE);
return false;
}
return $this->_exponentiate($s);
}
/**
* MGF1
*
* See {@link http://tools.ietf.org/html/rfc3447#appendix-B.2.1 RFC3447#appendix-B.2.1}.
*
* @access private
* @param String $mgfSeed
* @param Integer $mgfLen
* @return String
*/
function _mgf1($mgfSeed, $maskLen)
{
// if $maskLen would yield strings larger than 4GB, PKCS#1 suggests a "Mask too long" error be output.
$t = '';
$count = ceil($maskLen / $this->mgfHLen);
for ($i = 0; $i < $count; $i++) {
$c = pack('N', $i);
$t.= $this->mgfHash->hash($mgfSeed . $c);
}
return substr($t, 0, $maskLen);
}
/**
* RSAES-OAEP-ENCRYPT
*
* See {@link http://tools.ietf.org/html/rfc3447#section-7.1.1 RFC3447#section-7.1.1} and
* {http://en.wikipedia.org/wiki/Optimal_Asymmetric_Encryption_Padding OAES}.
*
* @access private
* @param String $m
* @param String $l
* @return String
*/
function _rsaes_oaep_encrypt($m, $l = '')
{
$mLen = strlen($m);
// Length checking
// if $l is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error
// be output.
if ($mLen > $this->k - 2 * $this->hLen - 2) {
user_error('Message too long', E_USER_NOTICE);
return false;
}
// EME-OAEP encoding
$lHash = $this->hash->hash($l);
$ps = str_repeat(chr(0), $this->k - $mLen - 2 * $this->hLen - 2);
$db = $lHash . $ps . chr(1) . $m;
$seed = $this->_random($this->hLen);
$dbMask = $this->_mgf1($seed, $this->k - $this->hLen - 1);
$maskedDB = $db ^ $dbMask;
$seedMask = $this->_mgf1($maskedDB, $this->hLen);
$maskedSeed = $seed ^ $seedMask;
$em = chr(0) . $maskedSeed . $maskedDB;
// RSA encryption
$m = $this->_os2ip($em);
$c = $this->_rsaep($m);
$c = $this->_i2osp($c, $this->k);
// Output the ciphertext C
return $c;
}
/**
* RSAES-OAEP-DECRYPT
*
* See {@link http://tools.ietf.org/html/rfc3447#section-7.1.2 RFC3447#section-7.1.2}. The fact that the error
* messages aren't distinguishable from one another hinders debugging, but, to quote from RFC3447#section-7.1.2:
*
* Note. Care must be taken to ensure that an opponent cannot
* distinguish the different error conditions in Step 3.g, whether by
* error message or timing, or, more generally, learn partial
* information about the encoded message EM. Otherwise an opponent may
* be able to obtain useful information about the decryption of the
* ciphertext C, leading to a chosen-ciphertext attack such as the one
* observed by Manger [36].
*
* As for $l... to quote from {@link http://tools.ietf.org/html/rfc3447#page-17 RFC3447#page-17}:
*
* Both the encryption and the decryption operations of RSAES-OAEP take
* the value of a label L as input. In this version of PKCS #1, L is
* the empty string; other uses of the label are outside the scope of
* this document.
*
* @access private
* @param String $c
* @param String $l
* @return String
*/
function _rsaes_oaep_decrypt($c, $l = '')
{
// Length checking
// if $l is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error
// be output.
if (strlen($c) != $this->k || $this->k < 2 * $this->hLen + 2) {
user_error('Decryption error', E_USER_NOTICE);
return false;
}
// RSA decryption
$c = $this->_os2ip($c);
$m = $this->_rsadp($c);
if ($m === false) {
user_error('Decryption error', E_USER_NOTICE);
return false;
}
$em = $this->_i2osp($m, $this->k);
// EME-OAEP decoding
$lHash = $this->hash->hash($l);
$y = ord($em[0]);
$maskedSeed = substr($em, 1, $this->hLen);
$maskedDB = substr($em, $this->hLen + 1);
$seedMask = $this->_mgf1($maskedDB, $this->hLen);
$seed = $maskedSeed ^ $seedMask;
$dbMask = $this->_mgf1($seed, $this->k - $this->hLen - 1);
$db = $maskedDB ^ $dbMask;
$lHash2 = substr($db, 0, $this->hLen);
$m = substr($db, $this->hLen);
if ($lHash != $lHash2) {
user_error('Decryption error', E_USER_NOTICE);
return false;
}
$m = ltrim($m, chr(0));
if (ord($m[0]) != 1) {
user_error('Decryption error', E_USER_NOTICE);
return false;
}
// Output the message M
return substr($m, 1);
}
/**
* RSAES-PKCS1-V1_5-ENCRYPT
*
* See {@link http://tools.ietf.org/html/rfc3447#section-7.2.1 RFC3447#section-7.2.1}.
*
* @access private
* @param String $m
* @return String
*/
function _rsaes_pkcs1_v1_5_encrypt($m)
{
$mLen = strlen($m);
// Length checking
if ($mLen > $this->k - 11) {
user_error('Message too long', E_USER_NOTICE);
return false;
}
// EME-PKCS1-v1_5 encoding
$ps = $this->_random($this->k - $mLen - 3, true);
$em = chr(0) . chr(2) . $ps . chr(0) . $m;
// RSA encryption
$m = $this->_os2ip($em);
$c = $this->_rsaep($m);
$c = $this->_i2osp($c, $this->k);
// Output the ciphertext C
return $c;
}
/**
* RSAES-PKCS1-V1_5-DECRYPT
*
* See {@link http://tools.ietf.org/html/rfc3447#section-7.2.2 RFC3447#section-7.2.2}.
*
* For compatability purposes, this function departs slightly from the description given in RFC3447.
* The reason being that RFC2313#section-8.1 (PKCS#1 v1.5) states that ciphertext's encrypted by the
* private key should have the second byte set to either 0 or 1 and that ciphertext's encrypted by the
* public key should have the second byte set to 2. In RFC3447 (PKCS#1 v2.1), the second byte is supposed
* to be 2 regardless of which key is used. for compatability purposes, we'll just check to make sure the
* second byte is 2 or less. If it is, we'll accept the decrypted string as valid.
*
* As a consequence of this, a private key encrypted ciphertext produced with Crypt_RSA may not decrypt
* with a strictly PKCS#1 v1.5 compliant RSA implementation. Public key encrypted ciphertext's should but
* not private key encrypted ciphertext's.
*
* @access private
* @param String $c
* @return String
*/
function _rsaes_pkcs1_v1_5_decrypt($c)
{
// Length checking
if (strlen($c) != $this->k) { // or if k < 11
user_error('Decryption error', E_USER_NOTICE);
return false;
}
// RSA decryption
$c = $this->_os2ip($c);
$m = $this->_rsadp($c);
if ($m === false) {
user_error('Decryption error', E_USER_NOTICE);
return false;
}
$em = $this->_i2osp($m, $this->k);
// EME-PKCS1-v1_5 decoding
if (ord($em[0]) != 0 || ord($em[1]) > 2) {
user_error('Decryption error', E_USER_NOTICE);
return false;
}
$ps = substr($em, 2, strpos($em, chr(0), 2) - 2);
$m = substr($em, strlen($ps) + 3);
if (strlen($ps) < 8) {
user_error('Decryption error', E_USER_NOTICE);
return false;
}
// Output M
return $m;
}
/**
* EMSA-PSS-ENCODE
*
* See {@link http://tools.ietf.org/html/rfc3447#section-9.1.1 RFC3447#section-9.1.1}.
*
* @access private
* @param String $m
* @param Integer $emBits
*/
function _emsa_pss_encode($m, $emBits)
{
// if $m is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error
// be output.
$emLen = ($emBits + 1) >> 3; // ie. ceil($emBits / 8)
$sLen = $this->sLen == false ? $this->hLen : $this->sLen;
$mHash = $this->hash->hash($m);
if ($emLen < $this->hLen + $sLen + 2) {
user_error('Encoding error', E_USER_NOTICE);
return false;
}
$salt = $this->_random($sLen);
$m2 = "\0\0\0\0\0\0\0\0" . $mHash . $salt;
$h = $this->hash->hash($m2);
$ps = str_repeat(chr(0), $emLen - $sLen - $this->hLen - 2);
$db = $ps . chr(1) . $salt;
$dbMask = $this->_mgf1($h, $emLen - $this->hLen - 1);
$maskedDB = $db ^ $dbMask;
$maskedDB[0] = ~chr(0xFF << ($emBits & 7)) & $maskedDB[0];
$em = $maskedDB . $h . chr(0xBC);
return $em;
}
/**
* EMSA-PSS-VERIFY
*
* See {@link http://tools.ietf.org/html/rfc3447#section-9.1.2 RFC3447#section-9.1.2}.
*
* @access private
* @param String $m
* @param String $em
* @param Integer $emBits
* @return String
*/
function _emsa_pss_verify($m, $em, $emBits)
{
// if $m is larger than two million terrabytes and you're using sha1, PKCS#1 suggests a "Label too long" error
// be output.
$emLen = ($emBits + 1) >> 3; // ie. ceil($emBits / 8);
$sLen = $this->sLen == false ? $this->hLen : $this->sLen;
$mHash = $this->hash->hash($m);
if ($emLen < $this->hLen + $sLen + 2) {
return false;
}
if ($em[strlen($em) - 1] != chr(0xBC)) {
return false;
}
$maskedDB = substr($em, 0, $em - $this->hLen - 1);
$h = substr($em, $em - $this->hLen - 1, $this->hLen);
$temp = chr(0xFF << ($emBits & 7));
if ((~$maskedDB[0] & $temp) != $temp) {
return false;
}
$dbMask = $this->_mgf1($h, $emLen - $this->hLen - 1);
$db = $maskedDB ^ $dbMask;
$db[0] = ~chr(0xFF << ($emBits & 7)) & $db[0];
$temp = $emLen - $this->hLen - $sLen - 2;
if (substr($db, 0, $temp) != str_repeat(chr(0), $temp) || ord($db[$temp]) != 1) {
return false;
}
$salt = substr($db, $temp + 1); // should be $sLen long
$m2 = "\0\0\0\0\0\0\0\0" . $mHash . $salt;
$h2 = $this->hash->hash($m2);
return $h == $h2;
}
/**
* RSASSA-PSS-SIGN
*
* See {@link http://tools.ietf.org/html/rfc3447#section-8.1.1 RFC3447#section-8.1.1}.
*
* @access private
* @param String $m
* @return String
*/
function _rsassa_pss_sign($m)
{
// EMSA-PSS encoding
$em = $this->_emsa_pss_encode($m, 8 * $this->k - 1);
// RSA signature
$m = $this->_os2ip($em);
$s = $this->_rsasp1($m);
$s = $this->_i2osp($s, $this->k);
// Output the signature S
return $s;
}
/**
* RSASSA-PSS-VERIFY
*
* See {@link http://tools.ietf.org/html/rfc3447#section-8.1.2 RFC3447#section-8.1.2}.
*
* @access private
* @param String $m
* @param String $s
* @return String
*/
function _rsassa_pss_verify($m, $s)
{
// Length checking
if (strlen($s) != $this->k) {
user_error('Invalid signature', E_USER_NOTICE);
return false;
}
// RSA verification
$modBits = 8 * $this->k;
$s2 = $this->_os2ip($s);
$m2 = $this->_rsavp1($s2);
if ($m2 === false) {
user_error('Invalid signature', E_USER_NOTICE);
return false;
}
$em = $this->_i2osp($m2, $modBits >> 3);
if ($em === false) {
user_error('Invalid signature', E_USER_NOTICE);
return false;
}
// EMSA-PSS verification
return $this->_emsa_pss_verify($m, $em, $modBits - 1);
}
/**
* EMSA-PKCS1-V1_5-ENCODE
*
* See {@link http://tools.ietf.org/html/rfc3447#section-9.2 RFC3447#section-9.2}.
*
* @access private
* @param String $m
* @param Integer $emLen
* @return String
*/
function _emsa_pkcs1_v1_5_encode($m, $emLen)
{
$h = $this->hash->hash($m);
if ($h === false) {
return false;
}
// see http://tools.ietf.org/html/rfc3447#page-43
switch ($this->hashName) {
case 'md2':
$t = pack('H*', '3020300c06082a864886f70d020205000410');
break;
case 'md5':
$t = pack('H*', '3020300c06082a864886f70d020505000410');
break;
case 'sha1':
$t = pack('H*', '3021300906052b0e03021a05000414');
break;
case 'sha256':
$t = pack('H*', '3031300d060960864801650304020105000420');
break;
case 'sha384':
$t = pack('H*', '3041300d060960864801650304020205000430');
break;
case 'sha512':
$t = pack('H*', '3051300d060960864801650304020305000440');
}
$t.= $h;
$tLen = strlen($t);
if ($emLen < $tLen + 11) {
user_error('Intended encoded message length too short', E_USER_NOTICE);
return false;
}
$ps = str_repeat(chr(0xFF), $emLen - $tLen - 3);
$em = "\0\1$ps\0$t";
return $em;
}
/**
* RSASSA-PKCS1-V1_5-SIGN
*
* See {@link http://tools.ietf.org/html/rfc3447#section-8.2.1 RFC3447#section-8.2.1}.
*
* @access private
* @param String $m
* @return String
*/
function _rsassa_pkcs1_v1_5_sign($m)
{
// EMSA-PKCS1-v1_5 encoding
$em = $this->_emsa_pkcs1_v1_5_encode($m, $this->k);
if ($em === false) {
user_error('RSA modulus too short', E_USER_NOTICE);
return false;
}
// RSA signature
$m = $this->_os2ip($em);
$s = $this->_rsasp1($m);
$s = $this->_i2osp($s, $this->k);
// Output the signature S
return $s;
}
/**
* RSASSA-PKCS1-V1_5-VERIFY
*
* See {@link http://tools.ietf.org/html/rfc3447#section-8.2.2 RFC3447#section-8.2.2}.
*
* @access private
* @param String $m
* @return String
*/
function _rsassa_pkcs1_v1_5_verify($m, $s)
{
// Length checking
if (strlen($s) != $this->k) {
user_error('Invalid signature', E_USER_NOTICE);
return false;
}
// RSA verification
$s = $this->_os2ip($s);
$m2 = $this->_rsavp1($s);
if ($m2 === false) {
user_error('Invalid signature', E_USER_NOTICE);
return false;
}
$em = $this->_i2osp($m2, $this->k);
if ($em === false) {
user_error('Invalid signature', E_USER_NOTICE);
return false;
}
// EMSA-PKCS1-v1_5 encoding
$em2 = $this->_emsa_pkcs1_v1_5_encode($m, $this->k);
if ($em2 === false) {
user_error('RSA modulus too short', E_USER_NOTICE);
return false;
}
// Compare
return $em === $em2;
}
/**
* Set Encryption Mode
*
* Valid values include CRYPT_RSA_ENCRYPTION_OAEP and CRYPT_RSA_ENCRYPTION_PKCS1.
*
* @access public
* @param Integer $mode
*/
function setEncryptionMode($mode)
{
$this->encryptionMode = $mode;
}
/**
* Set Signature Mode
*
* Valid values include CRYPT_RSA_SIGNATURE_PSS and CRYPT_RSA_SIGNATURE_PKCS1
*
* @access public
* @param Integer $mode
*/
function setSignatureMode($mode)
{
$this->signatureMode = $mode;
}
/**
* Encryption
*
* Both CRYPT_RSA_ENCRYPTION_OAEP and CRYPT_RSA_ENCRYPTION_PKCS1 both place limits on how long $plaintext can be.
* If $plaintext exceeds those limits it will be broken up so that it does and the resultant ciphertext's will
* be concatenated together.
*
* @see decrypt()
* @access public
* @param String $plaintext
* @return String
*/
function encrypt($plaintext)
{
switch ($this->encryptionMode) {
case CRYPT_RSA_ENCRYPTION_PKCS1:
$length = $this->k - 11;
if ($length <= 0) {
return false;
}
$plaintext = str_split($plaintext, $length);
$ciphertext = '';
foreach ($plaintext as $m) {
$ciphertext.= $this->_rsaes_pkcs1_v1_5_encrypt($m);
}
return $ciphertext;
//case CRYPT_RSA_ENCRYPTION_OAEP:
default:
$length = $this->k - 2 * $this->hLen - 2;
if ($length <= 0) {
return false;
}
$plaintext = str_split($plaintext, $length);
$ciphertext = '';
foreach ($plaintext as $m) {
$ciphertext.= $this->_rsaes_oaep_encrypt($m);
}
return $ciphertext;
}
}
/**
* Decryption
*
* @see encrypt()
* @access public
* @param String $plaintext
* @return String
*/
function decrypt($ciphertext)
{
if ($this->k <= 0) {
return false;
}
$ciphertext = str_split($ciphertext, $this->k);
$plaintext = '';
switch ($this->encryptionMode) {
case CRYPT_RSA_ENCRYPTION_PKCS1:
$decrypt = '_rsaes_pkcs1_v1_5_decrypt';
break;
//case CRYPT_RSA_ENCRYPTION_OAEP:
default:
$decrypt = '_rsaes_oaep_decrypt';
}
foreach ($ciphertext as $c) {
$temp = $this->$decrypt($c);
if ($temp === false) {
return false;
}
$plaintext.= $temp;
}
return $plaintext;
}
/**
* Create a signature
*
* @see verify()
* @access public
* @param String $message
* @return String
*/
function sign($message)
{
if (empty($this->modulus) || empty($this->exponent)) {
return false;
}
switch ($this->signatureMode) {
case CRYPT_RSA_SIGNATURE_PKCS1:
return $this->_rsassa_pkcs1_v1_5_sign($message);
//case CRYPT_RSA_SIGNATURE_PSS:
default:
return $this->_rsassa_pss_sign($message);
}
}
/**
* Verifies a signature
*
* @see sign()
* @access public
* @param String $message
* @param String $signature
* @return Boolean
*/
function verify($message, $signature)
{
if (empty($this->modulus) || empty($this->exponent)) {
return false;
}
switch ($this->signatureMode) {
case CRYPT_RSA_SIGNATURE_PKCS1:
return $this->_rsassa_pkcs1_v1_5_verify($message, $signature);
//case CRYPT_RSA_SIGNATURE_PSS:
default:
return $this->_rsassa_pss_verify($message, $signature);
}
}
}