requires = CRYPT()
If a key is specified, CRYPT uses the HMAC algorithm. The key may contain a prefix that determines the algorithm to use with HMAC, for example SHA512:
requires = CRYPT(key='sha512:thisisthekey')
By default, CRYPT uses random salt, such that each result is different. To use a constant salt value, specify its value:
requires = CRYPT(salt=False)
The resulting hash takes the form alg$salt$hash, where alg is the hash algorithm used, salt is the salt string (which can be empty), and hash is the algorithm's output. Consequently, the hash is self-identifying, allowing, for example, the algorithm to be changed without invalidating previous hashes. The key, however, must remain the same.
requires = CRYPT(min_length=5)