The erlsha2 library application implements the SHA-2 Secure Hash Standard (SHA-224, SHA-256, SHA-384, SHA-512) using Erlang NIFs. (It also provides pure Erlang implementations, though they are much slower than the C NIF implementations.) It also includes HMAC wrappers for the SHA-2 functions.

See the following links for details:

• Secure Hash Standard (PDF)
• Wikipedia SHA1 article

The code implemented here was written by simply following the algorithm descriptions provided in the standard. Provided functions follow the same style as those found in the standard Erlang crypto module: for each hash variant there's a simple function returning a binary digest and a set of three functions for initializing a digest context, updating the context with additional data to be hashed, and finalizing the context to get a binary digest result.

This implementation replaces and obsoletes the original pure Erlang implementation.

The erlsha2 app is built with rebar, which must be in the command PATH.

I don't use Windows at all so I doubt it builds there. I don't know of any reason it shouldn't work there, though; you'll just have to build it manually. If nothing else, you could comment out the on_load directive in the Erlang file to prevent it from loading the NIF implementation, thereby gaining access to the pure Erlang implementation instead, but note that it's much slower than the C code.

If you run into any build trouble, first make sure the version of rebar you're using is reasonably up to date.

The erlsha2 app requires Erlang R14B or later.