Hash a string and print it to stdout

hashstring.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

__author__ = "Gregory Sitnin <sitnin@gmail.com>"
__copyright__ = "Gregory Sitnin, 2012"
__version__ = "1.0"


import sys
import argparse
import hashlib

try:
    import bcrypt
except ImportError:
    pass

try:
    import scrypt
    from random import randint
    from base64 import b64encode, b64decode

    def randstr(length):
        return ''.join(chr(randint(0, 255)) for i in range(length))

    def scrypt_hash_password(password, maxtime=0.5, datalength=64):
        return scrypt.encrypt(randstr(datalength), password, maxtime=maxtime)

    def scrypt_verify_password(hashed_password, guessed_password, maxtime=0.5):
        try:
            scrypt.decrypt(hashed_password, guessed_password, maxtime)
            return True
        except scrypt.error:
            return False

except ImportError:
    pass


def parse_args():
    args_parser = argparse.ArgumentParser(version=__version__,
        description="Hash a string and print it to stdout",
        epilog="NOTE: This program is capable of hashing with bcrypt and scrypt if the corresponding python modules installed (py-bcrypt, scrypt). Other hashing routines using standard hashlib module."
        )
    subparsers = args_parser.add_subparsers(dest="method", help="hashing method")

    string_parser = argparse.ArgumentParser(add_help=False)
    string_parser.add_argument('string', help='string to hash')
    string_parser.add_argument('-v', '--verbose', action="store_true", help='verbose output')

    subparsers.add_parser('md5', parents=[string_parser])
    subparsers.add_parser('sha1', parents=[string_parser])
    subparsers.add_parser('sha256', parents=[string_parser])
    subparsers.add_parser('sha384', parents=[string_parser])
    subparsers.add_parser('sha512', parents=[string_parser])

    try:
        bcrypt
        bcrypt_parser = subparsers.add_parser('bcrypt', parents=[string_parser])
        bcrypt_parser.add_argument('-r', '--rounds', type=int, default=10, help='hashing rounds')
    except NameError:
        pass

    try:
        scrypt
        scrypt_parser = subparsers.add_parser('scrypt', parents=[string_parser])
        scrypt_parser.add_argument('-l', '--length', type=int, default=64, help='data length')
        scrypt_parser.add_argument('-t', '--time', type=float, default=0.05, help='minimum timespan to decrypt')
    except NameError:
        pass

    return args_parser.parse_args()


if __name__ == "__main__":
    args = parse_args()
    strhash = ""
    verified = False

    if args.method == "md5":
        strhash = hashlib.md5(args.string).hexdigest()
        verified = True

    elif args.method == "sha1":
        strhash = hashlib.sha1(args.string).hexdigest()
        verified = True

    elif args.method == "sha256":
        strhash = hashlib.sha256(args.string).hexdigest()
        verified = True

    elif args.method == "sha384":
        strhash = hashlib.sha384(args.string).hexdigest()
        verified = True

    elif args.method == "sha512":
        strhash = hashlib.sha512(args.string).hexdigest()
        verified = True

    elif args.method == "scrypt":
        strhash = b64encode(scrypt.encrypt(randstr(args.length), args.string, args.time))
        verified = scrypt_verify_password(b64decode(strhash), args.string, args.time * 1.5)  # WORKAROUND: sometimes, library exceeds decryption time limit and fails verification. so decrypt timespan extended

    elif args.method == "bcrypt":
        strhash = bcrypt.hashpw(args.string, bcrypt.gensalt(args.rounds))
        verified = strhash == bcrypt.hashpw(args.string, strhash)

    if args.verbose:
        print("stringhash v%s (c) %s" % (__version__, __copyright__))

    if len(strhash) > 0 and args.verbose:
        print("HASHED: %s\nLENGTH: %d\nSTATUS: %s" % (strhash, len(strhash), "Verified" if verified else "Not verified"))
        if args.method == "scrypt":
            print("WARNING: Output of the hashing function is base64-wrapped")
    elif len(strhash) > 0:
        print(strhash)
    else:
        print("error while hashing")
        sys.exit(1)