nelmio/NelmioSecurityBundle — pull request #13 by ruudk (2013-03-10 17:21:10+00:00)
Title: Removed the error suppression in Encrypter

If you don't have mcrypt installed enabling the Encrypted cookies feature will cause a blank screen. This is because the function calls to mcrypt_ are suppressed.

Maybe it would be even better to do a check in the Configuration.php file to see if mcrypt is installed?