diff --git a/src/Utility/Crypto/Mcrypt.php b/src/Utility/Crypto/Mcrypt.php
index 95ba7d70db6..2efce6a8388 100644
--- a/src/Utility/Crypto/Mcrypt.php
+++ b/src/Utility/Crypto/Mcrypt.php
@@ -31,6 +31,7 @@ class Mcrypt {
  * @param string $key Key to use as the encryption key for encrypted data.
  * @param string $operation Operation to perform, encrypt or decrypt
  * @throws \LogicException When there are errors.
+ * @return string Encrytped binary string data, or decrypted data depending on operation.
  */
 	public static function rijndael($text, $key, $operation) {
 		$algorithm = MCRYPT_RIJNDAEL_256;
diff --git a/src/Utility/Crypto/OpenSsl.php b/src/Utility/Crypto/OpenSsl.php
index 5bc6cfb43a2..203a164ff77 100644
--- a/src/Utility/Crypto/OpenSsl.php
+++ b/src/Utility/Crypto/OpenSsl.php
@@ -28,13 +28,13 @@
 class OpenSsl {
 
 /**
- * Encrypts/Decrypts a text using the given key using rijndael method.
+ * Not implemented
  *
  * @param string $text Encrypted string to decrypt, normal string to encrypt
  * @param string $key Key to use as the encryption key for encrypted data.
  * @param string $operation Operation to perform, encrypt or decrypt
- * @throws \InvalidArgumentException When there are errors.
- * @return string Encrypted/Decrypted string
+ * @throws \LogicException Rijndael compatibility does not exist with Openssl.
+ * @return void
  */
 	public static function rijndael($text, $key, $operation) {
 		throw new \LogicException('rijndael is not compatible with OpenSSL. Use mcrypt instead.');
diff --git a/src/Utility/Security.php b/src/Utility/Security.php
index c551f661b3e..d207b59b084 100644
--- a/src/Utility/Security.php
+++ b/src/Utility/Security.php
@@ -102,6 +102,7 @@ public static function setHash($hash) {
  *
  * @param object $instance The crypto instance to use.
  * @return object Crypto instance.
+ * @throws \InvalidArgumentException When no compatible crypto extension is available.
  */
 	public static function engine($instance = null) {
 		if ($instance === null && static::$_instance === null) {