py-bcrypt is a Python wrapper of OpenBSDs Blowfish password hashing code, as described in "A Future-Adaptable Password Scheme" by Niels Provos and David Mazi¨¨res. This system hashes passwords using a version of Bruce Schneiers Blowfish block cipher with modifications designed to raise the cost of off-line password cracking and frustrate fast hardware implementation. The computation cost of the algorithm depends on a parameter, so it can be increased as computers get faster.
