bcrypt for Python河豚密码哈希运算

py-bcrypt-0.4 released 25-Aug-2013; including Python3 support, Windows compilation fixes and support for a KDF mode If you are using a previous version, please upgrade to py-bcrypt-0.3 or later. It fixes a [security problem](https://code.google.com/p/py-bcrypt/source/detail?r=3bc365ff43736d26ff37e9f2a4084f37b381b569) py-bcrypt is a Python wrapper of OpenBSD"s Blowfish password hashing code, as described in "A Future-Adaptable Password Scheme" by Niels Provos and David Mazières. This system hashes passwords using a version of Bruce Schneier"s 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 is parametised, so it can be increased as computers get faster. The intent is to make a compromise of a password database less likely to result in an attacker gaining knowledge of the plaintext passwor