Openwall - crypt_blowfish

crypt_blowfish is an implementation of a modern password hashing algorithm, based on the Blowfish block cipher, provided via the crypt(3) and a reentrant interface. It is compatible with bcrypt by Niels Provos and David Mazieres as used in OpenBSD.

The most important property of bcrypt (and thus of crypt_blowfish) is that it is adaptable to future processor performance improvements, allowing you to arbitrarily increase the processing cost of checking a password while still maintaining compatibility with your older password hashes. Already now bcrypt hashes you would use are several orders of magnitude stronger than traditional Unix DES-based or FreeBSD-style MD5-based hashes.