380 lines
12 KiB
PHP
380 lines
12 KiB
PHP
<?php
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/**
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* Zend Framework
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*
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* LICENSE
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*
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* This source file is subject to the new BSD license that is bundled
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* with this package in the file LICENSE.txt.
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* It is also available through the world-wide-web at this URL:
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* http://framework.zend.com/license/new-bsd
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* If you did not receive a copy of the license and are unable to
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* obtain it through the world-wide-web, please send an email
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* to license@zend.com so we can send you a copy immediately.
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*
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* @category Zend
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* @package Zend_Crypt
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* @subpackage DiffieHellman
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* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
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* @license http://framework.zend.com/license/new-bsd New BSD License
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* @version $Id$
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*/
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/**
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* PHP implementation of the Diffie-Hellman public key encryption algorithm.
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* Allows two unassociated parties to establish a joint shared secret key
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* to be used in encrypting subsequent communications.
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*
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* @category Zend
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* @package Zend_Crypt
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* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
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* @license http://framework.zend.com/license/new-bsd New BSD License
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*/
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class Zend_Crypt_DiffieHellman
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{
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/**
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* Static flag to select whether to use PHP5.3's openssl extension
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* if available.
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*
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* @var boolean
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*/
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public static $useOpenssl = true;
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/**
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* Default large prime number; required by the algorithm.
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*
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* @var string
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*/
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private $_prime = null;
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/**
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* The default generator number. This number must be greater than 0 but
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* less than the prime number set.
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*
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* @var string
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*/
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private $_generator = null;
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/**
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* A private number set by the local user. It's optional and will
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* be generated if not set.
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*
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* @var string
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*/
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private $_privateKey = null;
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/**
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* BigInteger support object courtesy of Zend_Crypt_Math
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*
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* @var Zend_Crypt_Math_BigInteger
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*/
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private $_math = null;
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/**
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* The public key generated by this instance after calling generateKeys().
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*
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* @var string
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*/
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private $_publicKey = null;
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/**
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* The shared secret key resulting from a completed Diffie Hellman
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* exchange
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*
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* @var string
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*/
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private $_secretKey = null;
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/**
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* Constants
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*/
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const BINARY = 'binary';
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const NUMBER = 'number';
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const BTWOC = 'btwoc';
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/**
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* Constructor; if set construct the object using the parameter array to
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* set values for Prime, Generator and Private.
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* If a Private Key is not set, one will be generated at random.
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*
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* @param string $prime
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* @param string $generator
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* @param string $privateKey
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* @param string $privateKeyType
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* @return void
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*/
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public function __construct($prime, $generator, $privateKey = null, $privateKeyType = self::NUMBER)
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{
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$this->setPrime($prime);
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$this->setGenerator($generator);
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if (!is_null($privateKey)) {
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$this->setPrivateKey($privateKey, $privateKeyType);
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}
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$this->setBigIntegerMath();
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}
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/**
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* Generate own public key. If a private number has not already been
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* set, one will be generated at this stage.
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*
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* @return Zend_Crypt_DiffieHellman
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*/
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public function generateKeys()
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{
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if (function_exists('openssl_dh_compute_key') && self::$useOpenssl !== false) {
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$details = array();
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$details['p'] = $this->getPrime();
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$details['g'] = $this->getGenerator();
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if ($this->hasPrivateKey()) {
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$details['priv_key'] = $this->getPrivateKey();
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}
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$opensslKeyResource = openssl_pkey_new( array('dh' => $details) );
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$data = openssl_pkey_get_details($opensslKeyResource);
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$this->setPrivateKey($data['dh']['priv_key'], self::BINARY);
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$this->setPublicKey($data['dh']['pub_key'], self::BINARY);
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} else {
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// Private key is lazy generated in the absence of PHP 5.3's ext/openssl
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$publicKey = $this->_math->powmod($this->getGenerator(), $this->getPrivateKey(), $this->getPrime());
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$this->setPublicKey($publicKey);
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}
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return $this;
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}
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/**
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* Setter for the value of the public number
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*
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* @param string $number
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* @param string $type
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* @return Zend_Crypt_DiffieHellman
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*/
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public function setPublicKey($number, $type = self::NUMBER)
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{
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if ($type == self::BINARY) {
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$number = $this->_math->fromBinary($number);
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}
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if (!preg_match("/^\d+$/", $number)) {
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require_once('Zend/Crypt/DiffieHellman/Exception.php');
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throw new Zend_Crypt_DiffieHellman_Exception('invalid parameter; not a positive natural number');
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}
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$this->_publicKey = (string) $number;
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return $this;
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}
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/**
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* Returns own public key for communication to the second party to this
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* transaction.
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*
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* @param string $type
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* @return string
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*/
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public function getPublicKey($type = self::NUMBER)
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{
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if (is_null($this->_publicKey)) {
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require_once 'Zend/Crypt/DiffieHellman/Exception.php';
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throw new Zend_Crypt_DiffieHellman_Exception('A public key has not yet been generated using a prior call to generateKeys()');
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}
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if ($type == self::BINARY) {
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return $this->_math->toBinary($this->_publicKey);
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} elseif ($type == self::BTWOC) {
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return $this->_math->btwoc($this->_math->toBinary($this->_publicKey));
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}
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return $this->_publicKey;
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}
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/**
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* Compute the shared secret key based on the public key received from the
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* the second party to this transaction. This should agree to the secret
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* key the second party computes on our own public key.
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* Once in agreement, the key is known to only to both parties.
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* By default, the function expects the public key to be in binary form
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* which is the typical format when being transmitted.
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*
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* If you need the binary form of the shared secret key, call
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* getSharedSecretKey() with the optional parameter for Binary output.
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*
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* @param string $publicKey
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* @param string $type
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* @return mixed
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*/
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public function computeSecretKey($publicKey, $type = self::NUMBER, $output = self::NUMBER)
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{
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if ($type == self::BINARY) {
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$publicKey = $this->_math->fromBinary($publicKey);
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}
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if (!preg_match("/^\d+$/", $publicKey)) {
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require_once('Zend/Crypt/DiffieHellman/Exception.php');
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throw new Zend_Crypt_DiffieHellman_Exception('invalid parameter; not a positive natural number');
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}
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if (function_exists('openssl_dh_compute_key') && self::$useOpenssl !== false) {
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$this->_secretKey = openssl_dh_compute_key($publicKey, $this->getPublicKey());
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} else {
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$this->_secretKey = $this->_math->powmod($publicKey, $this->getPrivateKey(), $this->getPrime());
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}
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return $this->getSharedSecretKey($output);
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}
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/**
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* Return the computed shared secret key from the DiffieHellman transaction
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*
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* @param string $type
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* @return string
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*/
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public function getSharedSecretKey($type = self::NUMBER)
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{
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if (!isset($this->_secretKey)) {
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require_once('Zend/Crypt/DiffieHellman/Exception.php');
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throw new Zend_Crypt_DiffieHellman_Exception('A secret key has not yet been computed; call computeSecretKey()');
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}
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if ($type == self::BINARY) {
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return $this->_math->toBinary($this->_secretKey);
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} elseif ($type == self::BTWOC) {
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return $this->_math->btwoc($this->_math->toBinary($this->_secretKey));
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}
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return $this->_secretKey;
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}
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/**
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* Setter for the value of the prime number
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*
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* @param string $number
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* @return Zend_Crypt_DiffieHellman
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*/
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public function setPrime($number)
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{
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if (!preg_match("/^\d+$/", $number) || $number < 11) {
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require_once('Zend/Crypt/DiffieHellman/Exception.php');
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throw new Zend_Crypt_DiffieHellman_Exception('invalid parameter; not a positive natural number or too small: should be a large natural number prime');
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}
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$this->_prime = (string) $number;
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return $this;
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}
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/**
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* Getter for the value of the prime number
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*
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* @return string
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*/
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public function getPrime()
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{
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if (!isset($this->_prime)) {
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require_once('Zend/Crypt/DiffieHellman/Exception.php');
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throw new Zend_Crypt_DiffieHellman_Exception('No prime number has been set');
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}
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return $this->_prime;
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}
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/**
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* Setter for the value of the generator number
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*
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* @param string $number
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* @return Zend_Crypt_DiffieHellman
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*/
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public function setGenerator($number)
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{
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if (!preg_match("/^\d+$/", $number) || $number < 2) {
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require_once('Zend/Crypt/DiffieHellman/Exception.php');
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throw new Zend_Crypt_DiffieHellman_Exception('invalid parameter; not a positive natural number greater than 1');
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}
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$this->_generator = (string) $number;
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return $this;
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}
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/**
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* Getter for the value of the generator number
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*
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* @return string
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*/
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public function getGenerator()
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{
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if (!isset($this->_generator)) {
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require_once('Zend/Crypt/DiffieHellman/Exception.php');
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throw new Zend_Crypt_DiffieHellman_Exception('No generator number has been set');
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}
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return $this->_generator;
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}
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/**
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* Setter for the value of the private number
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*
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* @param string $number
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* @param string $type
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* @return Zend_Crypt_DiffieHellman
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*/
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public function setPrivateKey($number, $type = self::NUMBER)
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{
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if ($type == self::BINARY) {
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$number = $this->_math->fromBinary($number);
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}
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if (!preg_match("/^\d+$/", $number)) {
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require_once('Zend/Crypt/DiffieHellman/Exception.php');
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throw new Zend_Crypt_DiffieHellman_Exception('invalid parameter; not a positive natural number');
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}
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$this->_privateKey = (string) $number;
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return $this;
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}
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/**
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* Getter for the value of the private number
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*
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* @param string $type
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* @return string
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*/
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public function getPrivateKey($type = self::NUMBER)
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{
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if (!$this->hasPrivateKey()) {
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$this->setPrivateKey($this->_generatePrivateKey());
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}
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if ($type == self::BINARY) {
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return $this->_math->toBinary($this->_privateKey);
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} elseif ($type == self::BTWOC) {
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return $this->_math->btwoc($this->_math->toBinary($this->_privateKey));
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}
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return $this->_privateKey;
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}
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/**
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* Check whether a private key currently exists.
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*
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* @return boolean
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*/
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public function hasPrivateKey()
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{
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return isset($this->_privateKey);
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}
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/**
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* Setter to pass an extension parameter which is used to create
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* a specific BigInteger instance for a specific extension type.
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* Allows manual setting of the class in case of an extension
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* problem or bug.
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*
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* @param string $extension
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* @return void
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*/
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public function setBigIntegerMath($extension = null)
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{
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/**
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* @see Zend_Crypt_Math
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*/
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require_once 'Zend/Crypt/Math.php';
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$this->_math = new Zend_Crypt_Math($extension);
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}
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/**
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* In the event a private number/key has not been set by the user,
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* or generated by ext/openssl, a best attempt will be made to
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* generate a random key. Having a random number generator installed
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* on linux/bsd is highly recommended! The alternative is not recommended
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* for production unless without any other option.
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*
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* @return string
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*/
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protected function _generatePrivateKey()
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{
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$rand = $this->_math->rand($this->getGenerator(), $this->getPrime());
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return $rand;
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}
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} |