Update Rijndael.php

fix $length denomination

Author: bilogic

src/Crypt/Rijndael.php

@@ -80,7 +80,7 @@ public function setBlockLength($length)
         } elseif ($length < 4) {
             $length = 4;
         }
-        $this->cipher->setBlockLength($length);
+        $this->cipher->setBlockLength($length << 5);
     }
 
     /**
@@ -134,4 +134,4 @@ public function setPassword($password, $method = 'pbkdf2')
         $this->password = $args;
         $this->cipher->setPassword(...$args);
     }
-}
+}