diff --git a/phpseclib/Crypt/AES.php b/phpseclib/Crypt/AES.php
index 6f0a66ec..5e7153b3 100644
--- a/phpseclib/Crypt/AES.php
+++ b/phpseclib/Crypt/AES.php
@@ -114,13 +114,13 @@ class AES extends Rijndael
             $length = strlen($key);
             switch (true) {
                 case $length <= 16:
-                    $this->key_size = 16;
+                    $this->key_length = 16;
                     break;
                 case $length <= 24:
-                    $this->key_size = 24;
+                    $this->key_length = 24;
                     break;
                 default:
-                    $this->key_size = 32;
+                    $this->key_length = 32;
             }
             $this->_setEngine();
         }
diff --git a/phpseclib/Crypt/Base.php b/phpseclib/Crypt/Base.php
index 8845ee44..b02d8a6f 100644
--- a/phpseclib/Crypt/Base.php
+++ b/phpseclib/Crypt/Base.php
@@ -378,15 +378,6 @@ abstract class Base
      */
     var $cipher_name_openssl_ecb;
 
-    /**
-     * The default password key_size used by setPassword()
-     *
-     * @see \phpseclib\Crypt\Base::setPassword()
-     * @var int
-     * @access private
-     */
-    var $password_key_size = 32;
-
     /**
      * The default salt used by setPassword()
      *
@@ -440,6 +431,24 @@ abstract class Base
      */
     var $openssl_options;
 
+    /**
+     * Has the key length explicitly been set or should it be derived from the key, itself?
+     *
+     * @see self::setKeyLength()
+     * @var bool
+     * @access private
+     */
+    var $explicit_key_length = false;
+
+    /**
+     * Don't truncate / null pad key
+     *
+     * @see self::_clearBuffers()
+     * @var bool
+     * @access private
+     */
+    var $skip_key_adjustment = false;
+
     /**
      * Default Constructor.
      *
@@ -512,6 +521,43 @@ abstract class 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 in bits
+     *
+     * @access public
+     * @return int
+     */
+    function getKeyLength()
+    {
+        return $this->key_length << 3;
+    }
+
+    /**
+     * Returns the current block length in bits
+     *
+     * @access public
+     * @return int
+     */
+    function getBlockLength()
+    {
+        return $this->block_size << 3;
+    }
+
     /**
      * Sets the key.
      *
@@ -528,6 +574,11 @@ abstract class Base
      */
     function setKey($key)
     {
+        if (!$this->explicit_key_length) {
+            $this->setKeyLength(strlen($key) << 3);
+            $this->explicit_key_length = false;
+        }
+
         $this->key = $key;
         $this->changed = true;
         $this->_setEngine();
@@ -571,7 +622,7 @@ abstract class Base
                 if (isset($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_length : $this->key_length;
                 }
 
                 switch (true) {
@@ -1831,6 +1882,10 @@ abstract class 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_length), $this->key_length, "\0");
+        }
     }
 
     /**
diff --git a/phpseclib/Crypt/Blowfish.php b/phpseclib/Crypt/Blowfish.php
index 2c1d92c2..6d9df3d7 100644
--- a/phpseclib/Crypt/Blowfish.php
+++ b/phpseclib/Crypt/Blowfish.php
@@ -58,16 +58,6 @@ class Blowfish extends Base
      */
     var $block_size = 8;
 
-    /**
-     * The default password key_size used by setPassword()
-     *
-     * @see \phpseclib\Crypt\Base::password_key_size
-     * @see \phpseclib\Crypt\Base::setPassword()
-     * @var int
-     * @access private
-     */
-    var $password_key_size = 56;
-
     /**
      * The mcrypt specific name of the cipher
      *
@@ -283,37 +273,43 @@ class Blowfish extends Base
     var $kl;
 
     /**
-     * Sets the key.
+     * The Key Length (in bytes)
      *
-     * Keys can be of any length.  Blowfish, itself, requires the use of a key between 32 and max. 448-bits long.
-     * 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
-     * with mcrypt because mcrypt act this way with blowfish key's < 32 bits.
+     * @see \phpseclib\Crypt\Base::setKeyLength()
+     * @var int
+     * @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_length.  We could
+     *    derive this from $key_length 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_length = 16;
+
+    /**
+     * Sets the key length.
      *
-     * If the key is more than 448-bits, we trim the excess bits.
-     *
-     * If the key is not explicitly set, or empty, it'll be assumed a 128 bits key to be all null bytes.
+     * Key lengths can be between 32 and 448 bits.
      *
      * @access public
-     * @see \phpseclib\Crypt\Base::setKey()
-     * @param string $key
+     * @param int $length
      */
-    function setKey($key)
+    function setKeyLength($length)
     {
-        $keylength = strlen($key);
-
-        if (!$keylength) {
-            $key = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
-        } elseif ($keylength > 56) {
-            $key = substr($key, 0, 56);
+        if ($length < 32) {
+            $this->key_length = 7;
+        } elseif ($length > 448) {
+            $this->key_length = 56;
+        } else {
+            $this->key_length = $length >> 3;
         }
 
-        parent::setKey($key);
+        parent::setKeyLength($length);
     }
 
     /**
      * Test for engine validity
      *
-     * This is mainly just a wrapper to set things up for Crypt_Base::isValidEngine()
+     * This is mainly just a wrapper to set things up for \phpseclib\Crypt\Base::isValidEngine()
      *
      * @see \phpseclib\Crypt\Base::isValidEngine()
      * @param int $engine
@@ -323,7 +319,7 @@ class Blowfish extends Base
     function isValidEngine($engine)
     {
         if ($engine == self::ENGINE_OPENSSL) {
-            if (strlen($this->key) != 16) {
+            if ($this->key_length != 16) {
                 return false;
             }
             $this->cipher_name_openssl_ecb = 'bf-ecb';
diff --git a/phpseclib/Crypt/DES.php b/phpseclib/Crypt/DES.php
index 6964b60e..23f9045b 100644
--- a/phpseclib/Crypt/DES.php
+++ b/phpseclib/Crypt/DES.php
@@ -78,24 +78,13 @@ class DES extends Base
     var $block_size = 8;
 
     /**
-     * The Key
+     * Key Length (in bytes)
      *
-     * @see \phpseclib\Crypt\Base::key
-     * @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 \phpseclib\Crypt\Base::password_key_size
-     * @see \phpseclib\Crypt\Base::setPassword()
+     * @see \phpseclib\Crypt\Base::setKeyLength()
      * @var int
      * @access private
      */
-    var $password_key_size = 8;
+    var $key_length = 8;
 
     /**
      * The mcrypt specific name of the cipher
@@ -149,7 +138,7 @@ class DES extends Base
      * @var string
      * @access private
      */
-    var $key_size_max = 8;
+    var $key_length_max = 8;
 
     /**
      * The Key Schedule
@@ -594,7 +583,7 @@ class DES extends Base
     /**
      * Test for engine validity
      *
-     * This is mainly just a wrapper to set things up for Crypt_Base::isValidEngine()
+     * This is mainly just a wrapper to set things up for \phpseclib\Crypt\Base::isValidEngine()
      *
      * @see \phpseclib\Crypt\Base::isValidEngine()
      * @param int $engine
@@ -603,7 +592,7 @@ class DES extends Base
      */
     function isValidEngine($engine)
     {
-        if ($this->key_size_max == 8) {
+        if ($this->key_length_max == 8) {
             if ($engine == self::ENGINE_OPENSSL) {
                 $this->cipher_name_openssl_ecb = 'des-ecb';
                 $this->cipher_name_openssl = 'des-' . $this->_openssl_translate_mode();
@@ -632,8 +621,8 @@ class DES extends Base
     {
         // We check/cut here only up to max length of the key.
         // Key padding to the proper length will be done in _setupKey()
-        if (strlen($key) > $this->key_size_max) {
-            $key = substr($key, 0, $this->key_size_max);
+        if (strlen($key) > $this->key_length_max) {
+            $key = substr($key, 0, $this->key_length_max);
         }
 
         // Sets the key
diff --git a/phpseclib/Crypt/RC2.php b/phpseclib/Crypt/RC2.php
index f45407f2..e6f920af 100644
--- a/phpseclib/Crypt/RC2.php
+++ b/phpseclib/Crypt/RC2.php
@@ -77,14 +77,22 @@ class RC2 extends Base
     var $orig_key;
 
     /**
-     * The default password key_size used by setPassword()
+     * Don't truncate / null pad key
      *
-     * @see \phpseclib\Crypt\Base::password_key_size
-     * @see \phpseclib\Crypt\Base::setPassword()
+     * @see \phpseclib\Crypt\Base::_clearBuffers()
+     * @var bool
+     * @access private
+     */
+    var $skip_key_adjustment = true;
+
+    /**
+     * Key Length (in bytes)
+     *
+     * @see \phpseclib\Crypt\RC2::setKeyLength()
      * @var int
      * @access private
      */
-    var $password_key_size = 16; // = 128 bits
+    var $key_length = 16; // = 128 bits
 
     /**
      * The mcrypt specific name of the cipher
@@ -256,9 +264,9 @@ class RC2 extends Base
     /**
      * Test for engine validity
      *
-     * This is mainly just a wrapper to set things up for Crypt_Base::isValidEngine()
+     * This is mainly just a wrapper to set things up for \phpseclib\Crypt\Base::isValidEngine()
      *
-     * @see \phpseclib\Crypt\Base::Crypt_Base()
+     * @see \phpseclib\Crypt\Base::__construct()
      * @param int $engine
      * @access public
      * @return bool
@@ -267,7 +275,7 @@ class RC2 extends Base
     {
         switch ($engine) {
             case self::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';
@@ -278,7 +286,7 @@ class RC2 extends 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
@@ -294,6 +302,17 @@ class RC2 extends Base
         }
     }
 
+    /**
+     * Returns the current key length
+     *
+     * @access public
+     * @return int
+     */
+    function getKeyLength()
+    {
+        return $this->current_key_length;
+    }
+
     /**
      * Sets the key.
      *
@@ -349,13 +368,14 @@ class RC2 extends Base
         // Prepare the key for mcrypt.
         $l[0] = $this->invpitable[$l[0]];
         array_unshift($l, 'C*');
+
         parent::setKey(call_user_func_array('pack', $l));
     }
 
     /**
      * Encrypts a message.
      *
-     * Mostly a wrapper for Crypt_Base::encrypt, with some additional OpenSSL handling code
+     * Mostly a wrapper for \phpseclib\Crypt\Base::encrypt, with some additional OpenSSL handling code
      *
      * @see decrypt()
      * @access public
@@ -378,7 +398,7 @@ class RC2 extends Base
     /**
      * Decrypts a message.
      *
-     * Mostly a wrapper for Crypt_Base::decrypt, with some additional OpenSSL handling code
+     * Mostly a wrapper for \phpseclib\Crypt\Base::decrypt, with some additional OpenSSL handling code
      *
      * @see encrypt()
      * @access public
diff --git a/phpseclib/Crypt/RC4.php b/phpseclib/Crypt/RC4.php
index 0451ea5a..a5db1691 100644
--- a/phpseclib/Crypt/RC4.php
+++ b/phpseclib/Crypt/RC4.php
@@ -76,14 +76,13 @@ class RC4 extends Base
     var $block_size = 0;
 
     /**
-     * The default password key_size used by setPassword()
+     * Key Length (in bytes)
      *
-     * @see \phpseclib\Crypt\Base::password_key_size
-     * @see \phpseclib\Crypt\Base::setPassword()
+     * @see \phpseclib\Crypt\RC4::setKeyLength()
      * @var int
      * @access private
      */
-    var $password_key_size = 128; // = 1024 bits
+    var $key_length = 128; // = 1024 bits
 
     /**
      * The mcrypt specific name of the cipher
@@ -138,9 +137,9 @@ class RC4 extends Base
     /**
      * Test for engine validity
      *
-     * This is mainly just a wrapper to set things up for Crypt_Base::isValidEngine()
+     * This is mainly just a wrapper to set things up for \phpseclib\Crypt\Base::isValidEngine()
      *
-     * @see Crypt_Base::Crypt_Base()
+     * @see \phpseclib\Crypt\Base::__construct()
      * @param int $engine
      * @access public
      * @return bool
@@ -191,18 +190,24 @@ class RC4 extends 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
-     * be used.  If no key is explicitly set, it'll be assumed to be a single null byte.
+     * Keys can be between 1 and 256 bytes long.
      *
      * @access public
-     * @see \phpseclib\Crypt\Base::setKey()
-     * @param string $key
+     * @param int $length
      */
-    function setKey($key)
+    function setKeyLength($length)
     {
-        parent::setKey(substr($key, 0, 256));
+        if ($length < 8) {
+            $this->key_length = 1;
+        } elseif ($length > 2048) {
+            $this->key_length = 248;
+        } else {
+            $this->key_length = $length >> 3;
+        }
+
+        parent::setKeyLength($length);
     }
 
     /**
diff --git a/phpseclib/Crypt/Rijndael.php b/phpseclib/Crypt/Rijndael.php
index 38eb6f5f..334eaf9d 100644
--- a/phpseclib/Crypt/Rijndael.php
+++ b/phpseclib/Crypt/Rijndael.php
@@ -65,22 +65,12 @@ use phpseclib\Crypt\Base;
  */
 class Rijndael extends Base
 {
-    /**
-     * The default password key_size used by setPassword()
-     *
-     * @see \phpseclib\Crypt\Base::password_key_size
-     * @see \phpseclib\Crypt\Base::setPassword()
-     * @var int
-     * @access private
-     */
-    var $password_key_size = 16;
-
     /**
      * The mcrypt specific name of the cipher
      *
-     * Mcrypt is useable for 128/192/256-bit $block_size/$key_size. For 160/224 not.
+     * Mcrypt is useable for 128/192/256-bit $block_size/$key_length. For 160/224 not.
      * \phpseclib\Crypt\Rijndael determines automatically whether mcrypt is useable
-     * or not for the current $block_size/$key_size.
+     * or not for the current $block_size/$key_length.
      * In case of, $cipher_name_mcrypt will be set dynamically at run time accordingly.
      *
      * @see \phpseclib\Crypt\Base::cipher_name_mcrypt
@@ -101,15 +91,6 @@ class Rijndael extends 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
      *
@@ -142,17 +123,17 @@ class Rijndael extends Base
     var $Nb = 4;
 
     /**
-     * The Key Length
+     * The Key Length (in bytes)
      *
      * @see setKeyLength()
      * @var int
      * @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
+     *    because the encryption / decryption / key schedule creation requires this number and not $key_length.  We could
+     *    derive this from $key_length 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;
+    var $key_length = 16;
 
     /**
      * The Key Length divided by 32
@@ -190,48 +171,7 @@ class Rijndael extends Base
     var $kl;
 
     /**
-     * Sets the key.
-     *
-     * 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 \phpseclib\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
+     * 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.
@@ -253,25 +193,23 @@ class Rijndael extends 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;
+                $this->key_length = 16;
+                break;
+            case $length <= 160:
+                $this->key_length = 20;
                 break;
             case $length <= 192:
-                $this->key_size = 24;
+                $this->key_length = 24;
+                break;
+            case $length <= 224:
+                $this->key_length = 28;
                 break;
             default:
-                $this->key_size = 32;
+                $this->key_length = 32;
         }
 
-        $this->explicit_key_length = true;
-        $this->changed = true;
-        $this->_setEngine();
+        parent::setKeyLength($length);
     }
 
     /**
@@ -302,7 +240,7 @@ class Rijndael extends Base
      *
      * This is mainly just a wrapper to set things up for \phpseclib\Crypt\Base::isValidEngine()
      *
-     * @see \phpseclib\Crypt\Base::Crypt_Base()
+     * @see \phpseclib\Crypt\Base::__construct()
      * @param int $engine
      * @access public
      * @return bool
@@ -314,12 +252,12 @@ class Rijndael extends Base
                 if ($this->block_size != 16) {
                     return false;
                 }
-                $this->cipher_name_openssl_ecb = 'aes-' . ($this->key_size << 3) . '-ecb';
-                $this->cipher_name_openssl = 'aes-' . ($this->key_size << 3) . '-' . $this->_openssl_translate_mode();
+                $this->cipher_name_openssl_ecb = 'aes-' . ($this->key_length << 3) . '-ecb';
+                $this->cipher_name_openssl = 'aes-' . ($this->key_length << 3) . '-' . $this->_openssl_translate_mode();
                 break;
             case self::ENGINE_MCRYPT:
                 $this->cipher_name_mcrypt = 'rijndael-' . ($this->block_size << 3);
-                if ($this->key_size % 8) { // is it a 160/224-bit key?
+                if ($this->key_length % 8) { // is it a 160/224-bit key?
                     // mcrypt is not usable for them, only for 128/192/256-bit keys
                     return false;
                 }
@@ -328,18 +266,6 @@ class Rijndael extends Base
         return parent::isValidEngine($engine);
     }
 
-    /**
-     * Setup the \phpseclib\Crypt\Base::ENGINE_MCRYPT $engine
-     *
-     * @see \phpseclib\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
      *
@@ -550,15 +476,13 @@ class Rijndael extends 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 === $this->kl['block_size']) {
+        if (isset($this->kl['key']) && $this->key === $this->kl['key'] && $this->key_length === $this->kl['key_length'] && $this->block_size === $this->kl['block_size']) {
             // already expanded
             return;
         }
-        $this->kl = array('key' => $this->key, 'key_size' => $this->key_size, 'block_size' => $this->block_size);
+        $this->kl = array('key' => $this->key, 'key_length' => $this->key_length, 'block_size' => $this->block_size);
 
-        $this->Nk = $this->key_size >> 2;
+        $this->Nk = $this->key_length >> 2;
         // see Rijndael-ammended.pdf#page=44
         $this->Nr = max($this->Nk, $this->Nb) + 6;
 
@@ -668,9 +592,9 @@ class Rijndael extends Base
     /**
      * Provides the mixColumns and sboxes tables
      *
-     * @see Crypt_Rijndael:_encryptBlock()
-     * @see Crypt_Rijndael:_setupInlineCrypt()
-     * @see Crypt_Rijndael:_subWord()
+     * @see \phpseclib\Crypt\Rijndael:_encryptBlock()
+     * @see \phpseclib\Crypt\Rijndael:_setupInlineCrypt()
+     * @see \phpseclib\Crypt\Rijndael:_subWord()
      * @access private
      * @return array &$tables
      */
@@ -757,9 +681,9 @@ class Rijndael extends Base
     /**
      * Provides the inverse mixColumns and inverse sboxes tables
      *
-     * @see Crypt_Rijndael:_decryptBlock()
-     * @see Crypt_Rijndael:_setupInlineCrypt()
-     * @see Crypt_Rijndael:_setupKey()
+     * @see \phpseclib\Crypt\Rijndael:_decryptBlock()
+     * @see \phpseclib\Crypt\Rijndael:_setupInlineCrypt()
+     * @see \phpseclib\Crypt\Rijndael:_setupKey()
      * @access private
      * @return array &$tables
      */
diff --git a/phpseclib/Crypt/TripleDES.php b/phpseclib/Crypt/TripleDES.php
index b7de80c4..c5a0229e 100644
--- a/phpseclib/Crypt/TripleDES.php
+++ b/phpseclib/Crypt/TripleDES.php
@@ -64,15 +64,13 @@ class TripleDES extends DES
     const MODE_CBC3 = Base::MODE_CBC;
 
     /**
-     * The default password key_size used by setPassword()
+     * Key Length (in bytes)
      *
-     * @see \phpseclib\Crypt\DES::password_key_size
-     * @see \phpseclib\Crypt\Base::password_key_size
-     * @see \phpseclib\Crypt\Base::setPassword()
+     * @see \phpseclib\Crypt\TripleDES::setKeyLength()
      * @var int
      * @access private
      */
-    var $password_key_size = 24;
+    var $key_length = 24;
 
     /**
      * The default salt used by setPassword()
@@ -111,7 +109,7 @@ class TripleDES extends DES
      * @var string
      * @access private
      */
-    var $key_size_max = 24;
+    var $key_length_max = 24;
 
     /**
      * Internal flag whether using self::MODE_3CBC or not
@@ -189,7 +187,7 @@ class TripleDES extends DES
      *
      * This is mainly just a wrapper to set things up for \phpseclib\Crypt\Base::isValidEngine()
      *
-     * @see \phpseclib\Crypt\Base::Crypt_Base()
+     * @see \phpseclib\Crypt\Base::__construct()
      * @param int $engine
      * @access public
      * @return bool
@@ -225,6 +223,32 @@ class TripleDES extends DES
         }
     }
 
+    /**
+     * Sets the key length.
+     *
+     * Valid key lengths are 64, 128 and 192
+     *
+     * @see \phpseclib\Crypt\Base:setKeyLength()
+     * @access public
+     * @param int $length
+     */
+    function setKeyLength($length)
+    {
+        $length >>= 3;
+        switch (true) {
+            case $length <= 8:
+                $this->key_length = 8;
+                break;
+            case $length <= 16:
+                $this->key_length = 16;
+                break;
+            default:
+                $this->key_length = 24;
+        }
+
+        parent::setKeyLength($length);
+    }
+
     /**
      * Sets the key.
      *
@@ -242,7 +266,7 @@ class TripleDES extends DES
      */
     function setKey($key)
     {
-        $length = strlen($key);
+        $length = $this->explicit_key_length ? $this->key_length : strlen($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:
@@ -421,7 +445,7 @@ class TripleDES extends DES
     /**
      * Sets the internal crypt engine
      *
-     * @see \phpseclib\Crypt\Base::Crypt_Base()
+     * @see \phpseclib\Crypt\Base::__construct()
      * @see \phpseclib\Crypt\Base::setPreferredEngine()
      * @param int $engine
      * @access public
diff --git a/phpseclib/Crypt/Twofish.php b/phpseclib/Crypt/Twofish.php
index 1ddf87e1..623e9a6a 100644
--- a/phpseclib/Crypt/Twofish.php
+++ b/phpseclib/Crypt/Twofish.php
@@ -362,35 +362,36 @@ class Twofish extends Base
     var $kl;
 
     /**
-     * Sets the key.
+     * The Key Length (in bytes)
      *
-     * Keys can be of any length. Twofish, itself, requires the use of a key that's 128, 192 or 256-bits long.
-     * 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.
+     * @see Crypt_Twofish::setKeyLength()
+     * @var int
+     * @access private
+     */
+    var $key_length = 16;
+
+    /**
+     * Sets the key length.
      *
-     * If the key is not explicitly set, it'll be assumed a 128 bits key to be all null bytes.
+     * Valid key lengths are 128, 192 or 256 bits
      *
      * @access public
-     * @see \phpseclib\Crypt\Base::setKey()
-     * @param string $key
+     * @param int $length
      */
-    function setKey($key)
+    function setKeyLength($length)
     {
-        $keylength = strlen($key);
         switch (true) {
-            case $keylength <= 16:
-                $key = str_pad($key, 16, "\0");
+            case $length <= 128:
+                $this->key_length = 16;
                 break;
-            case $keylength <= 24:
-                $key = str_pad($key, 24, "\0");
+            case $length <= 192:
+                $this->key_length = 24;
                 break;
-            case $keylength < 32:
-                $key = str_pad($key, 32, "\0");
-                break;
-            case $keylength > 32:
-                $key = substr($key, 0, 32);
+            default:
+                $this->key_length = 32;
         }
-        parent::setKey($key);
+
+        parent::setKeyLength($length);
     }
 
     /**
diff --git a/tests/Unit/Crypt/AES/TestCase.php b/tests/Unit/Crypt/AES/TestCase.php
index 2ec21588..ba890c78 100644
--- a/tests/Unit/Crypt/AES/TestCase.php
+++ b/tests/Unit/Crypt/AES/TestCase.php
@@ -336,4 +336,39 @@ abstract class Unit_Crypt_AES_TestCase extends PhpseclibTestCase
         $result = bin2hex($aes->encrypt(pack('H*', '91fbef2d15a97816060bee1feaa49afe')));
         $this->assertSame($result, '1bc704f1bce135ceb810341b216d7abe');
     }
+
+    public function testGetKeyLengthDefault()
+    {
+        $aes = new AES();
+        $this->assertSame($aes->getKeyLength(), 128);
+    }
+
+    public function testGetKeyLengthWith192BitKey()
+    {
+        $aes = new AES();
+        $aes->setKey(str_repeat('a', 24));
+        $this->assertSame($aes->getKeyLength(), 192);
+    }
+
+    public function testSetKeyLengthWithLargerKey()
+    {
+        $aes = new 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 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);
+    }
 }