[exDM69]

It's not a very good idea to implement cryptography in a high level language such as PHP. Using a high level language opens a whole new world of pain when it comes to side channel attacks. Timing attacks, cache timing attacks and branch predictor attacks are much easier to protect yourself against if you write your crypto algorithms in C or, preferably, Assembly.

[jimktrains2]

C module?

[exDM69]

Writing your crypto with C and then calling it from another language such as PHP or Python is fine.