[tptacek]

Please don't use this library. Nacl is much safer, and in fact smaller.

If you're worried about size, use Tweetnacl:

TweetNaCl is the world's first auditable high-security cryptographic library. TweetNaCl fits into just 100 tweets while supporting all 25 of the C NaCl functions used by applications. TweetNaCl is a self-contained public-domain C library, so it can easily be integrated into applications.