- fixed a bug that prevented multi-prime RSA keys from loading

- slightly refactored Random.php
- implemented RSA blinding


git-svn-id: http://phpseclib.svn.sourceforge.net/svnroot/phpseclib/trunk@93 21d32557-59b3-4da0-833f-c5933fad653e

phpseclib/Crypt/RSA.php

@@ -62,7 +62,7 @@
  * @author     Jim Wigginton <terrafrost@php.net>
  * @copyright  MMIX Jim Wigginton
  * @license    http://www.gnu.org/licenses/lgpl.txt
- * @version    $Id: RSA.php,v 1.11 2010-02-26 03:40:25 terrafrost Exp $
+ * @version    $Id: RSA.php,v 1.12 2010-02-28 05:28:38 terrafrost Exp $
  * @link       http://phpseclib.sourceforge.net
  */
 
@@ -877,8 +877,9 @@ class Crypt_RSA {
                 $this->_string_shift($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_INTEGER) {
+                    if (ord($this->_string_shift($key)) != CRYPT_RSA_ASN1_SEQUENCE) {
                         return false;
                     }
                     $this->_decodeLength($key);
@@ -1286,31 +1287,86 @@ class Crypt_RSA {
         }
 
         $num_primes = count($this->primes);
-        $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 = $this->primes[1];
+        if (defined('CRYPT_RSA_DISABLE_BLINDING')) {
-        for ($i = 3; $i <= $num_primes; $i++) {
+            $m_i = array(
-            $m_i = $x->modPow($this->exponents[$i], $this->primes[$i]);
+                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 = $r->multiply($this->primes[$i - 1]);
+            $r = $this->primes[1];
+            for ($i = 3; $i <= $num_primes; $i++) {
+                $m_i = $x->modPow($this->exponents[$i], $this->primes[$i]);
 
-            $h = $m_i->subtract($m);
+                $r = $r->multiply($this->primes[$i - 1]);
-            $h = $h->multiply($this->coefficients[$i]);
-            list(, $h) = $h->divide($this->primes[$i]);
 
-            $m = $m->add($r->multiply($h));
+                $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 {
+            $m_i = array(
+                1 => $this->_blind($x, 1),
+                2 => $this->_blind($x, 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, $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 Integer $i
+     * @return Math_BigInteger
+     */
+    function _blind($x, $i)
+    {
+        static $one;
+        if (!isset($one)) {
+            $one = new Math_BigInteger(1);
+        }
+
+        $r = $one->random($one, $this->primes[$i]->subtract($one));
+        $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
      *
@@ -1886,7 +1942,7 @@ class Crypt_RSA {
 
         // Compare
 
-        return $em == $em2;
+        return $em === $em2;
     }
 
     /**

phpseclib/Crypt/Random.php

@@ -35,7 +35,7 @@
  * @author     Jim Wigginton <terrafrost@php.net>
  * @copyright  MMVII Jim Wigginton
  * @license    http://www.gnu.org/licenses/lgpl.txt
- * @version    $Id: Random.php,v 1.5 2010-02-19 22:39:44 terrafrost Exp $
+ * @version    $Id: Random.php,v 1.6 2010-02-28 05:28:38 terrafrost Exp $
  * @link       http://phpseclib.sourceforge.net
  */
 
@@ -56,6 +56,10 @@
  */
 function crypt_random($min = 0, $max = 0x7FFFFFFF)
 {
+    if ($min == $max) {
+        return $min;
+    }
+
     // see http://en.wikipedia.org/wiki//dev/random
     if (file_exists('/dev/urandom')) {
         $fp = fopen('/dev/urandom', 'rb');
@@ -89,47 +93,30 @@ function crypt_random($min = 0, $max = 0x7FFFFFFF)
     // in the browser and reloading the page.
 
     if (!isset($crypto)) {
+        $key = $iv = '';
+        for ($i = 0; $i < 8; $i++) {
+            $key.= pack('n', mt_rand(0, 0xFFFF));
+            $iv .= pack('n', mt_rand(0, 0xFFFF));
+        }
         switch (true) {
             case class_exists('Crypt_AES'):
-                $key = $iv = '';
-                for ($i = 0; $i < 8; $i++) {
-                    $key.= pack('n', mt_rand(0, 0xFFFF));
-                    $iv .= pack('n', mt_rand(0, 0xFFFF));
-                }
                 $crypto = new Crypt_AES(CRYPT_AES_MODE_CTR);
-                $crypto->setKey($key);
-                $crypto->setIV($iv);
                 break;
             case class_exists('Crypt_TripleDES'):
+                $crypto = new Crypt_TripleDES(CRYPT_DES_MODE_CTR);
+                break;
             case class_exists('Crypt_DES'):
-                $key = $iv = '';
+                $crypto = new Crypt_DES(CRYPT_DES_MODE_CTR);
-                for ($i = 0; $i < 4; $i++) {
-                    $key.= pack('n', mt_rand(0, 0xFFFF));
-                    $iv .= pack('n', mt_rand(0, 0xFFFF));
-                }
-                if (class_exists('Crypt_TripleDES')) {
-                    for ($i = 0; $i < 4; $i++) {
-                        $key.= pack('n', mt_rand(0, 0xFFFF));
-                    }
-                    $crypto = new Crypt_TripleDES(CRYPT_DES_MODE_CTR);
-                } else {
-                    $crypto = new Crypt_DES(CRYPT_DES_MODE_CTR);
-                }
-                $crypto->setKey($key);
-                $crypto->setIV($iv);
                 break;
             case class_exists('Crypt_RC4'):
-                $key = '';
-                for ($i = 0; $i < 8; $i++) {
-                    $key.= pack('n', mt_rand(0, 0xFFFF));
-                }
                 $crypto = new Crypt_RC4();
-                $crypto->setKey($key);
                 break;
             default:
                 extract(unpack('Nrandom', pack('H*', sha1(mt_rand(0, 0x7FFFFFFF)))));
                 return abs($random) % ($max - $min) + $min;
         }
+        $crypto->setKey($key);
+        $crypto->setIV($iv);
     }
 
     extract(unpack('Nrandom', $crypto->encrypt("\0\0\0\0")));