This is an RNCryptor-style API in front of an OpenSSL-compatible encryption format. I don't recommend the OpenSSL format. It has several security problems that the RNCryptor format was designed to improve on. This used to be part of RNCryptor respository. I don't support this module anymore, but I know some people are using it, so I'm making it available here.
rnapier/RNOpenSSLCryptor
(Not supported or recommended) RNCryptor-style API with OpenSSL-compatible backend for AES encryption
Objective-CMIT