TripleDES: updates to accomodate inner chaining

phpseclib/Crypt/TripleDES.php

@@ -68,13 +68,21 @@ if (!class_exists('Crypt_DES')) {
  *
  * Inner chaining is used by SSH-1 and is generally considered to be less secure then outer chaining (CRYPT_DES_MODE_CBC3).
  */
+define('CRYPT_MODE_3CBC', -2);
+/**
+ * BC version of the above.
+ */
 define('CRYPT_DES_MODE_3CBC', -2);
 /**
  * Encrypt / decrypt using outer chaining
  *
  * Outer chaining is used by SSH-2 and when the mode is set to CRYPT_DES_MODE_CBC.
  */
-define('CRYPT_DES_MODE_CBC3', CRYPT_DES_MODE_CBC);
+define('CRYPT_MODE_CBC3', CRYPT_MODE_CBC);
+/**
+ * BC version of the above.
+ */
+define('CRYPT_DES_MODE_CBC3', CRYPT_MODE_CBC3);
 /**#@-*/
 
 /**
@@ -190,20 +198,20 @@ class Crypt_TripleDES extends Crypt_DES
      * @param optional Integer $mode
      * @access public
      */
-    function Crypt_TripleDES($mode = CRYPT_DES_MODE_CBC)
+    function Crypt_TripleDES($mode = CRYPT_MODE_CBC)
     {
         switch ($mode) {
             // In case of CRYPT_DES_MODE_3CBC, we init as CRYPT_DES_MODE_CBC
             // and additional flag us internally as 3CBC
             case CRYPT_DES_MODE_3CBC:
-                parent::Crypt_Base(CRYPT_DES_MODE_CBC);
+                parent::Crypt_Base(CRYPT_MODE_CBC);
                 $this->mode_3cbc = true;
 
                 // This three $des'es will do the 3CBC work (if $key > 64bits)
                 $this->des = array(
-                    new Crypt_DES(CRYPT_DES_MODE_CBC),
+                    new Crypt_DES(CRYPT_MODE_CBC),
-                    new Crypt_DES(CRYPT_DES_MODE_CBC),
+                    new Crypt_DES(CRYPT_MODE_CBC),
-                    new Crypt_DES(CRYPT_DES_MODE_CBC),
+                    new Crypt_DES(CRYPT_MODE_CBC),
                 );
 
                 // we're going to be doing the padding, ourselves, so disable it in the Crypt_DES objects
@@ -308,7 +316,7 @@ class Crypt_TripleDES extends Crypt_DES
     function encrypt($plaintext)
     {
         // parent::en/decrypt() is able to do all the work for all modes and keylengths,
-        // except for: CRYPT_DES_MODE_3CBC (inner chaining CBC) with a key > 64bits
+        // except for: CRYPT_MODE_3CBC (inner chaining CBC) with a key > 64bits
 
         // if the key is smaller then 8, do what we'd normally do
         if ($this->mode_3cbc && strlen($this->key) > 8) {
@@ -455,19 +463,19 @@ class Crypt_TripleDES extends Crypt_DES
      * Sets the internal crypt engine
      *
      * @see Crypt_Base::Crypt_Base()
-     * @see Crypt_Base::setEngine()
+     * @see Crypt_Base::setPreferredEngine()
-     * @param optional Integer $engine
+     * @param Integer $engine
      * @access public
      * @return Integer
      */
-    function setEngine($engine = CRYPT_DES_MODE_MCRYPT)
+    function setPreferredEngine($engine)
     {
         if ($this->mode_3cbc) {
-            $this->des[0]->setEngine($engine);
+            $this->des[0]->setPreferredEngine($engine);
-            $this->des[1]->setEngine($engine);
+            $this->des[1]->setPreferredEngine($engine);
-            $this->des[2]->setEngine($engine);
+            $this->des[2]->setPreferredEngine($engine);
         }
 
-        return parent::setEngine($engine);
+        return parent::setPreferredEngine($engine);
     }
 }

tests/Unit/Crypt/TripleDESTest.php

@@ -9,14 +9,14 @@ require_once 'Crypt/TripleDES.php';
 
 class Unit_Crypt_TripleDESTest extends PhpseclibTestCase
 {
+    var $engines = array(
+        CRYPT_ENGINE_INTERNAL => 'internal',
+        CRYPT_ENGINE_MCRYPT => 'mcrypt',
+        CRYPT_ENGINE_OPENSSL => 'OpenSSL',
+    );
+
     public function engineVectors()
     {
-        $engines = array(
-            CRYPT_ENGINE_INTERNAL => 'internal',
-            CRYPT_ENGINE_MCRYPT => 'mcrypt',
-            CRYPT_ENGINE_OPENSSL => 'OpenSSL',
-        );
-
         // tests from http://csrc.nist.gov/publications/nistpubs/800-20/800-20.pdf#page=273
         $tests = array(
             // Table A.1
@@ -88,7 +88,7 @@ class Unit_Crypt_TripleDESTest extends PhpseclibTestCase
         );
         $result = array();
         // @codingStandardsIgnoreStart
-        foreach ($engines as $engine => $engineName) 
+        foreach ($this->engines as $engine => $engineName) 
         foreach ($tests as $test)
             $result[] = array($engine, $engineName, $test[0], $test[1], $test[2]);
         // @codingStandardsIgnoreEnd
@@ -160,4 +160,23 @@ class Unit_Crypt_TripleDESTest extends PhpseclibTestCase
         $plaintext = bin2hex($plaintext);
         $this->assertEquals($result, $expected, "Failed asserting that $plaintext yielded expected output in $engineName engine");
     }
+
+    public function testInnerChaining()
+    {
+        // regular CBC returns
+        //           e089b6d84708c6bc80be6c2da82bd19a79ffe11f02933ac1
+        $expected = 'e089b6d84708c6bc6f04c8971121603d7be2861efae0f3f5';
+
+        $des = new Crypt_TripleDES(CRYPT_DES_MODE_3CBC);
+        $des->setKey('abcdefghijklmnopqrstuvwx');
+
+        for ($this->engines as $engine->$engineName) {
+            $des->setPreferredEngine($engine);
+            if (!$des->isValidEngine($engine)) {
+	        self::markTestSkipped('Unable to initialize ' . $engineName . ' engine');
+            }
+            $result = bin2hex($des->encrypt(str_repeat('a', 16));
+            $this->assertEquals($result, $expected, "Failed asserting inner chainin worked correctly in $engineName engine");
+        }
+    }
 }