diff --git a/mailer.rst b/mailer.rst
index e7b1794eb30..eff89f78027 100644
--- a/mailer.rst
+++ b/mailer.rst
@@ -656,6 +656,11 @@ and it will select the appropriate certificate depending on the ``To`` option::
     $firstEncryptedEmail = $encrypter->encrypt($firstEmail);
     $secondEncryptedEmail = $encrypter->encrypt($secondEmail);
 
+.. tip::
+
+    The ``SMimeEncrypter`` class defines a second argument to choose
+    an algorithm to encrypt the message. the cipher must be one of these PHP constants: https://www.php.net/manual/en/openssl.ciphers.php
+    
 Sending Messages Async
 ----------------------