smarkets/erlang-bcrypt — pull request #9 by russor (2012-11-13 05:37:28+00:00)
Title: This change makes bcrypt_nif thread safe

Without it, multiple threads calling to bcrypt_nif can result in bad hashes coming back. If you're lucky, you'll get nulls in unexpected places and attempts to verify the hash will get a bcrypt failure; if you're not, you'll get a syntactically valid but incorrect hash back.

I'm using bcyrpt_nif directly, not using the worker interface. If you're using the worker interface you should be OK, because it only does one bcrypt at a time.