<?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 1.14 2010/03/01 17:28:19 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}. * * @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); } } }