Pure-python implementation of the crypt(3) SHA2 functions.
Useful for creating crypt-compatible hashes from non-*nixes (like Windows and OS X), like when creating password hashes to initialize a *nix server with.
$ pip install pcrypt
API is identical to the built-in crypt module on *nix:
>>> import pcrypt, getpass
>>> print(pcrypt.crypt(getpass.getpass()))
$6$tyjS23QPnY6k37iD$7oM9nObOVQUQ<...>/x7VKbuiyqgT81
If you want to override the number of rounds used for hashing, you can specify the parameter rounds to crypt:
>>> print(pcrypt.crypt(getpass.getpass(), rounds=50000))
$6$rounds=50000$FEkeiFqoGiU6Bd3v$6jn8ZZ<...>uXKvs7XAbp.
The default number of rounds is 5000, same as for crypt(3).
To use SHA256 instead of the default SHA512:
>>> print(pcrypt.crypt(getpass.getpass(), pcrypt.METHOD_SHA256))
$5$Zcxyug8MUozUjGIQ$yqvzOQR<...>pnLMvpOhhmrOWfn5
If the second argument is given it must be either an existing salt string matching the
format $<algo>$(rounds=<rounds>$)?<salt>($<hash>)?, or one of pcrypt.METHOD_SHA256
or pcrypt.METHOD_SHA512.
Without specifying salt manually the module will generate a new salt and use the strongest hash function available.
As a little extra nugget, there's also a handy CLI to quickly generate a hash:
$ pcrypt -h
usage: pcrypt [-h] [-r ROUNDS] [-a {sha256,sha512}] [-s]
Compute a password hash for SHA256/SHA512 in crypt(3)-compatible format.
Password will be prompted for.
optional arguments:
-h, --help show this help message and exit
-r ROUNDS, --rounds ROUNDS
How many rounds of hashing to perform. More rounds are
slower, making it harder to reverse a hash through
brute force. Default: 5000
-a {sha256,sha512}, --algo {sha256,sha512}
Which algorithm to use. Default: sha512
-s, --single-prompt Don't ask to repeat the password
NB: You'd probably guess from this being a pure-python implementation of a compute-heavy operation, but I just have to say this explicitly: Do not use this for performance-critical applications! Performance is roughly five orders of magnitude slower than the plain C version.