diff --git a/user_guide/libraries/encryption.html b/user_guide/libraries/encryption.html
index ef941d5..124b647 100644
--- a/user_guide/libraries/encryption.html
+++ b/user_guide/libraries/encryption.html
@@ -132,6 +132,14 @@
 <br />
 $plaintext_string = $this->encrypt->decode($encrypted_string);</code>
 
+<p>You can optionally pass your encryption key via the second parameter if you don't want to use the one in your config file:</p>
+
+<code>
+$msg = 'My secret message';<br />
+$key = 'super-secret-key';<br />
+<br />
+$encrypted_string = $this->encrypt->decode($msg, $key);</code>
+
 
 <h2>$this->encrypt->set_cipher();</h2>