A quick and dirty patch for the Linux-pam (plugable authentication modules) pam_unix module in order to support the OpenBSD's blowfish crypt encoding. This patch also uses the /dev/urandom device, if it exists, to get the random numbers needed for salt. Bcrypt is well designed crypt function by Niels Provos and David Mazieres. However this patch is nothing more than a quick hack, do not use it in a productive environment. If you still want to use it after compiling just enter "bcrypt" where "md5" should be (in the pam configuration files), and (optional) specify the cost, by entering "cost=x", (x should be larger than 6 and less than 32). The paper of bcrypt can be found at: http://www.openbsd.org/papers/bcrypt-paper.ps.
Note that the patch for PAM is quite old, and based on an older version of my bcrypt. There is a new implementation (updated on October 2002) on the bcrypt tarball above. The license for this is GNU Lesser GPL.