easy_scrypt.py

import ctypes
import scrypt

# This only supports OSX right now:

libc = ctypes.CDLL('libc.dylib')


SCRYPT_MAXTIME = 0.5
SCRYPT_SEED_LENGTH = 64


def randstr(length):
    """ return length-sized random string using arc4random_uniform(3) """
    return ''.join(chr(libc.arc4random_uniform(0, 255)) for i in range(length))


def hash_password(password, maxtime=SCRYPT_MAXTIME, datalength=SCRYPT_SEED_LENGTH):
    """ return a hashed password using scrypt """
    return scrypt.encrypt(randstr(datalength), password, maxtime=maxtime)


def verify_password(hashed_password, guessed_password, maxtime=SCRYPT_MAXTIME):
    """ verify a password hashed with scrypt, returns True if guessed_password is valid """
    try:
        scrypt.decrypt(hashed_password, guessed_password, maxtime)
        return True
    except scrypt.error:
        return False