Esta característica está OBSOLETA en PHP 7.1.0. y ELIMINADA en PHP 7.2.0.
Las alternativas a esta función son:
Nota:
Esta extensión se ha movido al repositorio de » PECL y ya no se distribuye con PHP a partir de PHP 7.2.0.
This is an interface to the mcrypt library, which supports a wide variety of block algorithms such as DES, TripleDES, Blowfish (default), 3-WAY, SAFER-SK64, SAFER-SK128, TWOFISH, TEA, RC2 and GOST in CBC, OFB, CFB and ECB cipher modes. Additionally, it supports RC6 and IDEA which are considered "non-free". CFB/OFB are 8bit by default.