mirror of
https://github.com/danog/tgseclib.git
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586 lines
17 KiB
PHP
586 lines
17 KiB
PHP
<?php
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/**
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* Pure-PHP FIPS 186-4 compliant implementation of DSA.
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*
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* PHP version 5
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*
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* Here's an example of how to create signatures and verify signatures with this library:
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* <code>
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* <?php
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* include 'vendor/autoload.php';
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*
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* extract(\phpseclib\Crypt\DSA::createKey());
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*
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* $plaintext = 'terrafrost';
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*
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* $signature = $privatekey->sign($plaintext, 'ASN1');
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*
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* echo $publickey->verify($plaintext, $signature) ? 'verified' : 'unverified';
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* ?>
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* </code>
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*
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* @category Crypt
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* @package DSA
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* @author Jim Wigginton <terrafrost@php.net>
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* @copyright 2016 Jim Wigginton
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* @license http://www.opensource.org/licenses/mit-license.html MIT License
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* @link http://phpseclib.sourceforge.net
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*/
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namespace phpseclib\Crypt;
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use ParagonIE\ConstantTime\Base64;
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use phpseclib\File\ASN1;
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use phpseclib\Math\BigInteger;
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use phpseclib\Crypt\Common\AsymmetricKey;
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use phpseclib\Math\PrimeField;
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use phpseclib\Crypt\ECDSA\Signature\ASN1 as ASN1Signature;
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use phpseclib\Exception\UnsupportedOperationException;
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use phpseclib\Exception\NoKeyLoadedException;
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use phpseclib\Exception\InsufficientSetupException;
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/**
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* Pure-PHP FIPS 186-4 compliant implementation of DSA.
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*
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* @package DSA
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* @author Jim Wigginton <terrafrost@php.net>
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* @access public
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*/
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class DSA extends AsymmetricKey
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{
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/**
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* Algorithm Name
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*
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* @var string
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* @access private
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*/
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const ALGORITHM = 'DSA';
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/**
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* DSA Prime P
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*
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* @var \phpseclib\Math\BigInteger
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* @access private
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*/
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private $p;
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/**
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* DSA Group Order q
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*
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* Prime divisor of p-1
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*
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* @var \phpseclib\Math\BigInteger
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* @access private
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*/
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protected $q;
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/**
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* DSA Group Generator G
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*
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* @var \phpseclib\Math\BigInteger
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* @access private
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*/
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private $g;
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/**
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* DSA secret exponent x
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*
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* @var \phpseclib\Math\BigInteger
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* @access private
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*/
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protected $x;
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/**
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* DSA public key value y
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*
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* @var \phpseclib\Math\BigInteger
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* @access private
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*/
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private $y;
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/**
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* Create DSA parameters
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*
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* @access public
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* @param int $L
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* @param int $N
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* @return \phpseclib\Crypt\DSA|bool
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*/
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public static function createParameters($L = 2048, $N = 224)
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{
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self::initialize_static_variables();
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if (!isset(self::$engines['PHP'])) {
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self::useBestEngine();
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}
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switch (true) {
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case $N == 160:
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/*
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in FIPS 186-1 and 186-2 N was fixed at 160 whereas K had an upper bound of 1024.
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RFC 4253 (SSH Transport Layer Protocol) references FIPS 186-2 and as such most
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SSH DSA implementations only support keys with an N of 160.
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puttygen let's you set the size of L (but not the size of N) and uses 2048 as the
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default L value. that's not really compliant with any of the FIPS standards, however,
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for the purposes of maintaining compatibility with puttygen, we'll support it
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*/
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//case ($L >= 512 || $L <= 1024) && (($L & 0x3F) == 0) && $N == 160:
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// FIPS 186-3 changed this as follows:
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//case $L == 1024 && $N == 160:
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case $L == 2048 && $N == 224:
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case $L == 2048 && $N == 256:
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case $L == 3072 && $N == 256:
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break;
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default:
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return false;
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}
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$two = new BigInteger(2);
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$q = BigInteger::randomPrime($N);
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$divisor = $q->multiply($two);
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do {
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$x = BigInteger::random($L);
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list(, $c) = $x->divide($divisor);
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$p = $x->subtract($c->subtract(self::$one));
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} while ($p->getLength() != $L || !$p->isPrime());
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$p_1 = $p->subtract(self::$one);
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list($e) = $p_1->divide($q);
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// quoting http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf#page=50 ,
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// "h could be obtained from a random number generator or from a counter that
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// changes after each use". PuTTY (sshdssg.c) starts h off at 1 and increments
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// it on each loop. wikipedia says "commonly h = 2 is used" so we'll just do that
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$h = clone $two;
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while (true) {
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$g = $h->powMod($e, $p);
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if (!$g->equals(self::$one)) {
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break;
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}
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$h = $h->add(self::$one);
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}
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$dsa = new DSA();
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$dsa->p = $p;
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$dsa->q = $q;
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$dsa->g = $g;
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return $dsa;
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}
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/**
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* Create public / private key pair.
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*
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* This method is a bit polymorphic. It can take a DSA object (eg. pre-loaded with parameters),
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* L / N as two distinct parameters or no parameters (at which point L and N will be generated
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* with this method)
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*
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* Returns an array with the following two elements:
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* - 'privatekey': The private key.
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* - 'publickey': The public key.
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*
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* @param $args[]
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* @access public
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* @return array|DSA
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*/
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public static function createKey(...$args)
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{
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self::initialize_static_variables();
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if (!isset(self::$engines['PHP'])) {
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self::useBestEngine();
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}
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if (count($args) == 2 && is_int($args[0]) && is_int($args[1])) {
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$private = self::createParameters($args[0], $args[1]);
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} else if (count($args) == 1 && $args[0] instanceof DSA) {
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$private = clone $args[0];
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} else if (!count($args)) {
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$private = self::createParameters();
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} else {
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throw new InsufficientSetupException('Valid parameters are either two integers (L and N), a single DSA object or no parameters at all.');
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}
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$private->x = BigInteger::randomRange(self::$one, $private->q->subtract(self::$one));
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$private->y = $private->g->powMod($private->x, $private->p);
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$public = clone $private;
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unset($public->x);
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return ['privatekey' => $private, 'publickey' => $public];
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}
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/**
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* Loads a public or private key
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*
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* Returns true on success and false on failure (ie. an incorrect password was provided or the key was malformed)
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* @return bool
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* @access public
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* @param string $key
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* @param int|bool $type optional
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*/
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public function load($key, $type = false)
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{
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self::initialize_static_variables();
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if (!isset(self::$engines['PHP'])) {
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self::useBestEngine();
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}
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if ($key instanceof DSA) {
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$this->privateKeyFormat = $key->privateKeyFormat;
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$this->publicKeyFormat = $key->publicKeyFormat;
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$this->format = $key->format;
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$this->p = $key->p;
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$this->q = $key->q;
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$this->g = $key->g;
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$this->x = $key->x;
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$this->y = $key->y;
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$this->parametersFormat = $key->parametersFormat;
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return true;
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}
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$components = parent::load($key, $type);
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if ($components === false) {
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$this->format = null;
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$this->p = null;
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$this->q = null;
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$this->g = null;
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$this->x = null;
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$this->y = null;
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return false;
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}
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if (isset($components['p'])) {
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switch (true) {
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case isset($this->p) && !$this->p->equals($components['p']):
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case isset($this->q) && !$this->q->equals($components['q']):
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case isset($this->g) && !$this->g->equals($components['g']):
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$this->x = $this->y = null;
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}
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$this->p = $components['p'];
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$this->q = $components['q'];
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$this->g = $components['g'];
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}
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$this->x = isset($components['x']) ? $components['x'] : null;
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if (isset($components['y'])) {
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$this->y = $components['y'];
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}
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//} else if (isset($components['x'])) {
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// $this->y = $this->g->powMod($this->x, $this->p);
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//}
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return true;
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}
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/**
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* Returns the key size
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*
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* More specifically, this L (the length of DSA Prime P) and N (the length of DSA Group Order q)
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*
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* @access public
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* @return array
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*/
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public function getLength()
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{
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return isset($this->p) ?
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['L' => $this->p->getLength(), 'N' => $this->q->getLength()] :
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['L' => 0, 'N' => 0];
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}
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/**
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* Returns the private key
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*
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* PKCS1 DSA private keys contain x and y. PKCS8 DSA private keys just contain x
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* but y can be derived from x.
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*
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* @see self::getPublicKey()
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* @access public
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* @param string $type optional
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* @return mixed
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*/
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public function getPrivateKey($type = 'PKCS8')
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{
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$type = self::validatePlugin('Keys', $type, 'savePrivateKey');
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if ($type === false) {
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return false;
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}
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if (!isset($this->x)) {
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return false;
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}
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if (!isset($this->y)) {
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$this->y = $this->g->powMod($this->x, $this->p);
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}
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return $type::savePrivateKey($this->p, $this->q, $this->g, $this->y, $this->x, $this->password);
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}
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/**
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* Is the key a private key?
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*
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* @access public
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* @return bool
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*/
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public function isPrivateKey()
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{
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return isset($this->x);
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}
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/**
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* Is the key a public key?
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*
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* @access public
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* @return bool
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*/
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public function isPublicKey()
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{
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return isset($this->p);
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}
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/**
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* Returns the public key
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*
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* If you do "openssl rsa -in private.rsa -pubout -outform PEM" you get a PKCS8 formatted key
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* that contains a publicKeyAlgorithm AlgorithmIdentifier and a publicKey BIT STRING.
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* An AlgorithmIdentifier contains an OID and a parameters field. With RSA public keys this
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* parameters field is NULL. With DSA PKCS8 public keys it is not - it contains the p, q and g
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* variables. The publicKey BIT STRING contains, simply, the y variable. This can be verified
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* by getting a DSA PKCS8 public key:
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*
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* "openssl dsa -in private.dsa -pubout -outform PEM"
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*
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* ie. just swap out rsa with dsa in the rsa command above.
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*
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* A PKCS1 public key corresponds to the publicKey portion of the PKCS8 key. In the case of RSA
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* the publicKey portion /is/ the key. In the case of DSA it is not. You cannot verify a signature
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* without the parameters and the PKCS1 DSA public key format does not include the parameters.
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*
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* @see self::getPrivateKey()
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* @access public
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* @param string $type optional
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* @return mixed
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*/
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public function getPublicKey($type = null)
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{
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$returnObj = false;
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if ($type === null) {
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$returnObj = true;
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$type = 'PKCS8';
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}
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$type = self::validatePlugin('Keys', $type, 'savePublicKey');
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if ($type === false) {
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return false;
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}
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if (!isset($this->y)) {
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if (!isset($this->x) || !isset($this->p)) {
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return false;
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}
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$this->y = $this->g->powMod($this->x, $this->p);
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}
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$key = $type::savePublicKey($this->p, $this->q, $this->g, $this->y);
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if (!$returnObj) {
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return $key;
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}
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$public = clone $this;
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$public->load($key, 'PKCS8');
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return $public;
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}
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/**
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* Returns the parameters
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*
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* A public / private key is only returned if the currently loaded "key" contains an x or y
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* value.
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*
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* @see self::getPublicKey()
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* @see self::getPrivateKey()
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* @access public
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* @param string $type optional
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* @return mixed
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*/
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public function getParameters($type = 'PKCS1')
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{
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$type = self::validatePlugin('Keys', $type, 'saveParameters');
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if ($type === false) {
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return false;
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}
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if (!isset($this->p) || !isset($this->q) || !isset($this->g)) {
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return false;
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}
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return $type::saveParameters($this->p, $this->q, $this->g);
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}
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/**
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* Returns the current engine being used
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*
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* @see self::useInternalEngine()
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* @see self::useBestEngine()
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* @access public
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* @return string
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*/
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public function getEngine()
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{
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return self::$engines['OpenSSL'] && in_array($this->hash->getHash(), openssl_get_md_methods()) ?
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'OpenSSL' : 'PHP';
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}
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/**
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* Create a signature
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*
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* @see self::verify()
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* @access public
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* @param string $message
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* @param string $format optional
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* @return mixed
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*/
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public function sign($message, $format = 'ASN1')
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{
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$shortFormat = $format;
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$format = self::validatePlugin('Signature', $format);
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if ($format === false) {
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return false;
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}
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if (empty($this->x)) {
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if (empty($this->y)) {
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throw new NoKeyLoadedException('No key has been loaded');
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}
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throw new UnsupportedOperationException('A public key cannot be used to sign data');
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}
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if (empty($this->p)) {
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throw new InsufficientSetupException('DSA Prime P is not set');
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}
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if (self::$engines['OpenSSL'] && in_array($this->hash->getHash(), openssl_get_md_methods())) {
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$signature = '';
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$result = openssl_sign($message, $signature, $this->getPrivateKey(), $this->hash->getHash());
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if ($result) {
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if ($shortFormat == 'ASN1') {
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return $signature;
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}
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extract(ASN1Signature::load($signature));
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return $format::save($r, $s);
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}
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}
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$h = $this->hash->hash($message);
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$h = $this->bits2int($h);
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while (true) {
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$k = BigInteger::randomRange(self::$one, $this->q->subtract(self::$one));
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$r = $this->g->powMod($k, $this->p);
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list(, $r) = $r->divide($this->q);
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if ($r->equals(self::$zero)) {
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continue;
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}
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$kinv = $k->modInverse($this->q);
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$temp = $h->add($this->x->multiply($r));
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$temp = $kinv->multiply($temp);
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list(, $s) = $temp->divide($this->q);
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if (!$s->equals(self::$zero)) {
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break;
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}
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}
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// the following is an RFC6979 compliant implementation of deterministic DSA
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// it's unused because it's mainly intended for use when a good CSPRNG isn't
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// available. if phpseclib's CSPRNG isn't good then even key generation is
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// suspect
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/*
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$h1 = $this->hash->hash($message);
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$k = $this->computek($h1);
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$r = $this->g->powMod($k, $this->p);
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list(, $r) = $r->divide($this->q);
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$kinv = $k->modInverse($this->q);
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$h1 = $this->bits2int($h1);
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$temp = $h1->add($this->x->multiply($r));
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$temp = $kinv->multiply($temp);
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list(, $s) = $temp->divide($this->q);
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*/
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return $format::save($r, $s);
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}
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/**
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* Verify a signature
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*
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* @see self::verify()
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* @access public
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* @param string $message
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* @param string $signature
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* @param string $format optional
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* @return mixed
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*/
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public function verify($message, $signature, $format = 'ASN1')
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{
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$format = self::validatePlugin('Signature', $format);
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if ($format === false) {
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return false;
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}
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$params = $format::load($signature);
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if ($params === false || count($params) != 2) {
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return false;
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}
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extract($params);
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if (empty($this->y)) {
|
|
if (empty($this->x)) {
|
|
throw new NoKeyLoadedException('No key has been loaded');
|
|
}
|
|
throw new UnsupportedOperationException('A private key cannot be used to sign data');
|
|
}
|
|
|
|
if (empty($this->p)) {
|
|
throw new InsufficientSetupException('DSA Prime P is not set');
|
|
}
|
|
|
|
if (self::$engines['OpenSSL'] && in_array($this->hash->getHash(), openssl_get_md_methods())) {
|
|
$sig = $format != 'ASN1' ? ASN1Signature::save($r, $s) : $signature;
|
|
|
|
$result = openssl_verify($message, $sig, $this->getPublicKey(), $this->hash->getHash());
|
|
|
|
if ($result != -1) {
|
|
return (bool) $result;
|
|
}
|
|
}
|
|
|
|
$q_1 = $this->q->subtract(self::$one);
|
|
if (!$r->between(self::$one, $q_1) || !$s->between(self::$one, $q_1)) {
|
|
return false;
|
|
}
|
|
|
|
$w = $s->modInverse($this->q);
|
|
$h = $this->hash->hash($message);
|
|
$h = $this->bits2int($h);
|
|
list(, $u1) = $h->multiply($w)->divide($this->q);
|
|
list(, $u2) = $r->multiply($w)->divide($this->q);
|
|
$v1 = $this->g->powMod($u1, $this->p);
|
|
$v2 = $this->y->powMod($u2, $this->p);
|
|
list(, $v) = $v1->multiply($v2)->divide($this->p);
|
|
list(, $v) = $v->divide($this->q);
|
|
|
|
return $v->equals($r);
|
|
}
|
|
} |