Crypt: make it so the key length can be explicitly set for all ciphers

phpseclib/Crypt/Base.php

@@ -470,6 +470,24 @@ class Crypt_Base
      */
     var $openssl_options;
 
+    /**
+     * Has the key length explicitly been set or should it be derived from the key, itself?
+     *
+     * @see setKeyLength()
+     * @var bool
+     * @access private
+     */
+    var $explicit_key_length = false;
+
+    /**
+     * Don't truncate / null pad key
+     *
+     * @see Crypt_Base::_clearBuffers
+     * @var bool
+     * @access private
+     */
+    var $skip_key_adjustment = false;
+
     /**
      * Default Constructor.
      *
@@ -542,6 +560,32 @@ class Crypt_Base
         $this->changed = true;
     }
 
+    /**
+     * Sets the key length.
+     *
+     * Keys with explicitly set lengths need to be treated accordingly
+     *
+     * @access public
+     * @param int $length
+     */
+    function setKeyLength($length)
+    {
+        $this->explicit_key_length = true;
+        $this->changed = true;
+        $this->_setEngine();
+    }
+
+    /**
+     * Returns the current key length
+     *
+     * @access public
+     * @return int
+     */
+    function getKeyLength()
+    {
+        return $this->key_size << 3;
+    }
+
     /**
      * Sets the key.
      *
@@ -558,6 +602,11 @@ class Crypt_Base
      */
     function setKey($key)
     {
+        if (!$this->explicit_key_length) {
+            $this->setKeyLength(strlen($key) << 3);
+            $this->explicit_key_length = false;
+        }
+
         $this->key = $key;
         $this->changed = true;
         $this->_setEngine();
@@ -601,7 +650,7 @@ class Crypt_Base
                 if (isset($func_args[5])) {
                     $dkLen = $func_args[5];
                 } else {
-                    $dkLen = $method == 'pbkdf1' ? 2 * $this->password_key_size : $this->password_key_size;
+                    $dkLen = $method == 'pbkdf1' ? 2 * $this->key_size : $this->key_size;
                 }
 
                 switch (true) {
@@ -1873,6 +1922,10 @@ class Crypt_Base
         // mcrypt's handling of invalid's $iv:
         // $this->encryptIV = $this->decryptIV = strlen($this->iv) == $this->block_size ? $this->iv : str_repeat("\0", $this->block_size);
         $this->encryptIV = $this->decryptIV = str_pad(substr($this->iv, 0, $this->block_size), $this->block_size, "\0");
+
+        if (!$this->skip_key_adjustment) {
+            $this->key = str_pad(substr($this->key, 0, $this->key_size), $this->key_size, "\0");
+        }
     }
 
     /**

phpseclib/Crypt/Blowfish.php

@@ -120,16 +120,6 @@ class Crypt_Blowfish extends Crypt_Base
      */
     var $block_size = 8;
 
-    /**
-     * The default password key_size used by setPassword()
-     *
-     * @see Crypt_Base::password_key_size
-     * @see Crypt_Base::setPassword()
-     * @var int
-     * @access private
-     */
-    var $password_key_size = 56;
-
     /**
      * The namespace used by the cipher for its constants.
      *
@@ -354,31 +344,37 @@ class Crypt_Blowfish extends Crypt_Base
     var $kl;
 
     /**
-     * Sets the key.
+     * The Key Length
      *
-     * Keys can be of any length.  Blowfish, itself, requires the use of a key between 32 and max. 448-bits long.
+     * @see setKeyLength()
-     * If the key is less than 32-bits we NOT fill the key to 32bit but let the key as it is to be compatible
+     * @var int
-     * with mcrypt because mcrypt act this way with blowfish key's < 32 bits.
+     * @access private
+     * @internal The max value is 256 / 8 = 32, the min value is 128 / 8 = 16.  Exists in conjunction with $Nk
+     *    because the encryption / decryption / key schedule creation requires this number and not $key_size.  We could
+     *    derive this from $key_size or vice versa, but that'd mean we'd have to do multiple shift operations, so in lieu
+     *    of that, we'll just precompute it once.
+     */
+    var $key_size = 16;
+
+    /**
+     * Sets the key length.
      *
-     * If the key is more than 448-bits, we trim the excess bits.
+     * Key lengths can be between 32 and 448 bits.
-     *
-     * If the key is not explicitly set, or empty, it'll be assumed a 128 bits key to be all null bytes.
      *
      * @access public
-     * @see Crypt_Base::setKey()
+     * @param int $length
-     * @param string $key
      */
-    function setKey($key)
+    function setKeyLength($length)
     {
-        $keylength = strlen($key);
+        if ($length < 32) {
-
+            $this->key_size = 7;
-        if (!$keylength) {
+        } elseif ($length > 448) {
-            $key = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
+            $this->key_size = 56;
-        } elseif ($keylength > 56) {
+        } else {
-            $key = substr($key, 0, 56);
+            $this->key_size = $length >> 3;
         }
 
-        parent::setKey($key);
+        parent::setKeyLength($length);
     }
 
     /**
@@ -394,7 +390,7 @@ class Crypt_Blowfish extends Crypt_Base
     function isValidEngine($engine)
     {
         if ($engine == CRYPT_ENGINE_OPENSSL) {
-            if (strlen($this->key) != 16) {
+            if ($this->key_size != 16) {
                 return false;
             }
             $this->cipher_name_openssl_ecb = 'bf-ecb';

phpseclib/Crypt/DES.php

@@ -140,24 +140,13 @@ class Crypt_DES extends Crypt_Base
     var $block_size = 8;
 
     /**
-     * The Key
+     * Key Length
      *
-     * @see Crypt_Base::key
+     * @see Crypt_Base::setKeyLength()
-     * @see setKey()
-     * @var string
-     * @access private
-     */
-    var $key = "\0\0\0\0\0\0\0\0";
-
-    /**
-     * The default password key_size used by setPassword()
-     *
-     * @see Crypt_Base::password_key_size
-     * @see Crypt_Base::setPassword()
      * @var int
      * @access private
      */
-    var $password_key_size = 8;
+    var $key_size = 8;
 
     /**
      * The namespace used by the cipher for its constants.

phpseclib/Crypt/RC2.php

@@ -139,14 +139,22 @@ class Crypt_RC2 extends Crypt_Base
     var $orig_key;
 
     /**
-     * The default password key_size used by setPassword()
+     * Don't truncate / null pad key
      *
-     * @see Crypt_Base::password_key_size
+     * @see Crypt_Base::_clearBuffers
-     * @see Crypt_Base::setPassword()
+     * @var bool
+     * @access private
+     */
+    var $skip_key_adjustment = true;
+
+    /**
+     * Key Length
+     *
+     * @see Crypt_RC2::setKeyLength()
      * @var int
      * @access private
      */
-    var $password_key_size = 16; // = 128 bits
+    var $key_size = 16; // = 128 bits
 
     /**
      * The namespace used by the cipher for its constants.
@@ -366,7 +374,7 @@ class Crypt_RC2 extends Crypt_Base
     {
         switch ($engine) {
             case CRYPT_ENGINE_OPENSSL:
-                if ($this->current_key_length != 128 || strlen($this->orig_key) != 16) {
+                if ($this->current_key_length != 128 || strlen($this->orig_key) < 16) {
                     return false;
                 }
                 $this->cipher_name_openssl_ecb = 'rc2-ecb';
@@ -377,7 +385,7 @@ class Crypt_RC2 extends Crypt_Base
     }
 
     /**
-     * Sets the key length
+     * Sets the key length.
      *
      * Valid key lengths are 1 to 1024.
      * Calling this function after setting the key has no effect until the next
@@ -393,6 +401,17 @@ class Crypt_RC2 extends Crypt_Base
         }
     }
 
+    /**
+     * Returns the current key length
+     *
+     * @access public
+     * @return int
+     */
+    function getKeyLength()
+    {
+        return $this->current_key_length;
+    }
+
     /**
      * Sets the key.
      *
@@ -448,6 +467,7 @@ class Crypt_RC2 extends Crypt_Base
         // Prepare the key for mcrypt.
         $l[0] = $this->invpitable[$l[0]];
         array_unshift($l, 'C*');
+
         parent::setKey(call_user_func_array('pack', $l));
     }
 

phpseclib/Crypt/RC4.php

@@ -99,14 +99,13 @@ class Crypt_RC4 extends Crypt_Base
     var $block_size = 0;
 
     /**
-     * The default password key_size used by setPassword()
+     * Key Length
      *
-     * @see Crypt_Base::password_key_size
+     * @see Crypt_RC4::setKeyLength()
-     * @see Crypt_Base::setPassword()
      * @var int
      * @access private
      */
-    var $password_key_size = 128; // = 1024 bits
+    var $key_size = 128; // = 1024 bits
 
     /**
      * The namespace used by the cipher for its constants.
@@ -223,18 +222,24 @@ class Crypt_RC4 extends Crypt_Base
     }
 
     /**
-     * Sets the key.
+     * Sets the key length
      *
-     * Keys can be between 1 and 256 bytes long.  If they are longer then 256 bytes, the first 256 bytes will
+     * Keys can be between 1 and 256 bytes long.
-     * be used.  If no key is explicitly set, it'll be assumed to be a single null byte.
      *
      * @access public
-     * @see Crypt_Base::setKey()
+     * @param int $length
-     * @param string $key
      */
-    function setKey($key)
+    function setKeyLength($length)
     {
-        parent::setKey(substr($key, 0, 256));
+        if ($length < 8) {
+            $this->key_size = 1;
+        } elseif ($length > 2048) {
+            $this->key_size = 248;
+        } else {
+            $this->key_size = $length >> 3;
+        }
+
+        parent::setKeyLength($length);
     }
 
     /**

phpseclib/Crypt/Rijndael.php

@@ -127,16 +127,6 @@ define('CRYPT_RIJNDAEL_MODE_OFB', CRYPT_MODE_OFB);
  */
 class Crypt_Rijndael extends Crypt_Base
 {
-    /**
-     * The default password key_size used by setPassword()
-     *
-     * @see Crypt_Base::password_key_size
-     * @see Crypt_Base::setPassword()
-     * @var int
-     * @access private
-     */
-    var $password_key_size = 16;
-
     /**
      * The namespace used by the cipher for its constants.
      *
@@ -172,15 +162,6 @@ class Crypt_Rijndael extends Crypt_Base
      */
     var $password_default_salt = 'phpseclib';
 
-    /**
-     * Has the key length explicitly been set or should it be derived from the key, itself?
-     *
-     * @see setKeyLength()
-     * @var bool
-     * @access private
-     */
-    var $explicit_key_length = false;
-
     /**
      * The Key Schedule
      *
@@ -289,48 +270,7 @@ class Crypt_Rijndael extends Crypt_Base
     }
 
     /**
-     * Sets the key.
+     * Sets the key length.
-     *
-     * Keys can be of any length.  Rijndael, itself, requires the use of a key that's between 128-bits and 256-bits long and
-     * whose length is a multiple of 32.  If the key is less than 256-bits and the key length isn't set, we round the length
-     * up to the closest valid key length, padding $key with null bytes.  If the key is more than 256-bits, we trim the
-     * excess bits.
-     *
-     * If the key is not explicitly set, it'll be assumed to be all null bytes.
-     *
-     * Note: 160/224-bit keys must explicitly set by setKeyLength(), otherwise they will be round/pad up to 192/256 bits.
-     *
-     * @see Crypt_Base:setKey()
-     * @see setKeyLength()
-     * @access public
-     * @param string $key
-     */
-    function setKey($key)
-    {
-        if (!$this->explicit_key_length) {
-            $length = strlen($key);
-            switch (true) {
-                case $length <= 16:
-                    $this->key_size = 16;
-                    break;
-                case $length <= 20:
-                    $this->key_size = 20;
-                    break;
-                case $length <= 24:
-                    $this->key_size = 24;
-                    break;
-                case $length <= 28:
-                    $this->key_size = 28;
-                    break;
-                default:
-                    $this->key_size = 32;
-            }
-        }
-        parent::setKey($key);
-    }
-
-    /**
-     * Sets the key length
      *
      * Valid key lengths are 128, 160, 192, 224, and 256.  If the length is less than 128, it will be rounded up to
      * 128.  If the length is greater than 128 and invalid, it will be rounded down to the closest valid amount.
@@ -352,25 +292,23 @@ class Crypt_Rijndael extends Crypt_Base
     function setKeyLength($length)
     {
         switch (true) {
-            case $length == 160:
-                $this->key_size = 20;
-                break;
-            case $length == 224:
-                $this->key_size = 28;
-                break;
             case $length <= 128:
                 $this->key_size = 16;
                 break;
+            case $length <= 160:
+                $this->key_size = 20;
+                break;
             case $length <= 192:
                 $this->key_size = 24;
                 break;
+            case $length <= 224:
+                $this->key_size = 28;
+                break;
             default:
                 $this->key_size = 32;
         }
 
-        $this->explicit_key_length = true;
+        parent::setKeyLength($length);
-        $this->changed = true;
-        $this->_setEngine();
     }
 
     /**
@@ -427,18 +365,6 @@ class Crypt_Rijndael extends Crypt_Base
         return parent::isValidEngine($engine);
     }
 
-    /**
-     * Setup the CRYPT_ENGINE_MCRYPT $engine
-     *
-     * @see Crypt_Base::_setupMcrypt()
-     * @access private
-     */
-    function _setupMcrypt()
-    {
-        $this->key = str_pad(substr($this->key, 0, $this->key_size), $this->key_size, "\0");
-        parent::_setupMcrypt();
-    }
-
     /**
      * Encrypts a block
      *
@@ -649,8 +575,6 @@ class Crypt_Rijndael extends Crypt_Base
             0x7D000000, 0xFA000000, 0xEF000000, 0xC5000000, 0x91000000
         );
 
-        $this->key = str_pad(substr($this->key, 0, $this->key_size), $this->key_size, "\0");
-
         if (isset($this->kl['key']) && $this->key === $this->kl['key'] && $this->key_size === $this->kl['key_size'] && $this->block_size === $this->kl['block_size']) {
             // already expanded
             return;

phpseclib/Crypt/TripleDES.php

@@ -95,15 +95,13 @@ define('CRYPT_DES_MODE_CBC3', CRYPT_MODE_CBC3);
 class Crypt_TripleDES extends Crypt_DES
 {
     /**
-     * The default password key_size used by setPassword()
+     * Key Length
      *
-     * @see Crypt_DES::password_key_size
+     * @see Crypt_TripleDES::setKeyLength()
-     * @see Crypt_Base::password_key_size
-     * @see Crypt_Base::setPassword()
      * @var int
      * @access private
      */
-    var $password_key_size = 24;
+    var $key_size = 24;
 
     /**
      * The default salt used by setPassword()
@@ -266,6 +264,32 @@ class Crypt_TripleDES extends Crypt_DES
         }
     }
 
+    /**
+     * Sets the key length.
+     *
+     * Valid key lengths are 64, 128 and 192
+     *
+     * @see Crypt_Rijndael:setKeyLength()
+     * @access public
+     * @param int $length
+     */
+    function setKeyLength($length)
+    {
+        $length >>= 3;
+        switch (true) {
+            case $length <= 8:
+                $this->key_size = 8;
+                break;
+            case $length <= 16:
+                $this->key_size = 16;
+                break;
+            default:
+                $this->key_size = 24;
+        }
+
+        parent::setKeyLength($length);
+    }
+
     /**
      * Sets the key.
      *
@@ -283,7 +307,7 @@ class Crypt_TripleDES extends Crypt_DES
      */
     function setKey($key)
     {
-        $length = strlen($key);
+        $length = $this->explicit_key_length ? $this->key_size : strlen($key);
         if ($length > 8) {
             $key = str_pad(substr($key, 0, 24), 24, chr(0));
             // if $key is between 64 and 128-bits, use the first 64-bits as the last, per this:

phpseclib/Crypt/Twofish.php

@@ -433,35 +433,27 @@ class Crypt_Twofish extends Crypt_Base
     var $kl;
 
     /**
-     * Sets the key.
+     * Sets the key length.
      *
-     * Keys can be of any length. Twofish, itself, requires the use of a key that's 128, 192 or 256-bits long.
+     * Valid key lengths are 128, 192 or 256 bits
-     * If the key is less than 256-bits we round the length up to the closest valid key length,
-     * padding $key with null bytes. If the key is more than 256-bits, we trim the excess bits.
-     *
-     * If the key is not explicitly set, it'll be assumed a 128 bits key to be all null bytes.
      *
      * @access public
-     * @see Crypt_Base::setKey()
+     * @param int $length
-     * @param string $key
      */
-    function setKey($key)
+    function setKeyLength($length)
     {
-        $keylength = strlen($key);
         switch (true) {
-            case $keylength <= 16:
+            case $length <= 128:
-                $key = str_pad($key, 16, "\0");
+                $this->key_size = 16;
                 break;
-            case $keylength <= 24:
+            case $length <= 192:
-                $key = str_pad($key, 24, "\0");
+                $this->key_size = 24;
                 break;
-            case $keylength < 32:
+            default:
-                $key = str_pad($key, 32, "\0");
+                $this->key_size = 32;
-                break;
-            case $keylength > 32:
-                $key = substr($key, 0, 32);
         }
-        parent::setKey($key);
+
+        parent::setKeyLength($length);
     }
 
     /**

tests/Unit/Crypt/AES/TestCase.php

@@ -334,4 +334,39 @@ abstract class Unit_Crypt_AES_TestCase extends PhpseclibTestCase
         $result = bin2hex($aes->encrypt(pack('H*', '91fbef2d15a97816060bee1feaa49afe')));
         $this->assertSame($result, '1bc704f1bce135ceb810341b216d7abe');
     }
+
+    public function testGetKeyLengthDefault()
+    {
+        $aes = new Crypt_AES();
+        $this->assertSame($aes->getKeyLength(), 128);
+    }
+
+    public function testGetKeyLengthWith192BitKey()
+    {
+        $aes = new Crypt_AES();
+        $aes->setKey(str_repeat('a', 24));
+        $this->assertSame($aes->getKeyLength(), 192);
+    }
+
+    public function testSetKeyLengthWithLargerKey()
+    {
+        $aes = new Crypt_AES();
+        $aes->setKeyLength(128);
+        $aes->setKey(str_repeat('a', 24));
+        $this->assertSame($aes->getKeyLength(), 128);
+        $ciphertext = bin2hex($aes->encrypt('a'));
+        $this->assertSame($ciphertext, '82b7b068dfc60ed2a46893b69fecd6c2');
+        $this->assertSame($aes->getKeyLength(), 128);
+    }
+
+    public function testSetKeyLengthWithSmallerKey()
+    {
+        $aes = new Crypt_AES();
+        $aes->setKeyLength(256);
+        $aes->setKey(str_repeat('a', 16));
+        $this->assertSame($aes->getKeyLength(), 256);
+        $ciphertext = bin2hex($aes->encrypt('a'));
+        $this->assertSame($ciphertext, 'fd4250c0d234aa7e1aa592820aa8406b');
+        $this->assertSame($aes->getKeyLength(), 256);
+    }
 }