Fastest path to Lua SHA256 RFC-2104 compliant HMAC signature?

Question

I'm running Debian Linux, and for a Lua script I need to create a SHA256 checksum to authenticate requests to Amazon Web Services. They don't say for sure but it looks as if they may want a base64 encoding of the resulting SHA256 checksum.

• I'd be happy if someone had done a Lua binding.
• I'd be content if someone could help me figure out how to use the command-line /usr/bin/sha256sum for this purpose.
• I'd settle for a pointer to C code and deal with the hassle of the binding and the base64 encoding myself.

I surely don't need to reimplement SHA256 for myself; if someone has an implementation in ANSI standard C that they like, please let me know. Or a better solution!

Answer 1

How about LuaCrypto, a front-end for OpenSSL:

http://luacrypto.luaforge.net/

Answer 2

It looks like mushclient has already written a Lua wrapper for a SHA-256 library.

Answer 3

A work-around might be the free signing service at http://apisigning.com/