python-drbg:适用于Python的加密安全PRNG

This Python library provides a cryptographically secure pseudorandom number generator. Specifically, it implements **HMAC_DRBG** (SHA-512) as specified in [NIST SP 800-90A](http://csrc.nist.gov/publications/nistpubs/800-90A/SP800-90A.pdf). For simplicity, this library currently does not track the seed period, so the `generate` function always returns the requested number of bytes. It is the user's responsibility to periodically reseed the PRNG. This library is tested with NIST-provided test vectors. To run the tests: $ python hmac_drbg_tests.py Passed all 224 tests. **See also**: [go-crypto](https://github.com/davidlazar/go-crypto).