Unique, reproducible per-domain password generation.

pwgen.py

#!/usr/bin/env python

## Imports
import base64
import hashlib
import argparse

from getpass import getpass

## Module Constants
VERSION = "pwgen.py 1.0"
DESCRIPTION = "Generates unique, long, reproducible passwords."
EPILOG  = "See http://bit.ly/1ROIahb for more information."


def get_password(attempts=0):
    password = getpass("Enter master passphrase: ").strip()
    confirm  = getpass("Enter same passphrase again: ").strip()

    if password != confirm:
        if attempts < 3:
            print "Passwords do not match, try again."
            return get_password(attempts+1)
        else:
            raise Exception("Password attempt maximum, stretch fingers and try again!")

    if not password:
        raise Exception("You must supply a base password for the generator!")
    return password


def main(args):
    """
    Use raw input to collect information from the command line.
    """
    # Create the base password string
    password = "{}{}{}".format(args.domain[0], args.salt, get_password())

    # Hash and encode the base password
    password = base64.b64encode(hashlib.sha256(password).digest())

    return password


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        version=VERSION, description=DESCRIPTION, epilog=EPILOG,
    )

    # Create the arguments
    parser.add_argument(
        '-s', '--salt', default='', type=str,
        help='salt or increment to add to password',
    )

    parser.add_argument(
        'domain', nargs=1,
        help='the domain of the site to generate a password for',
    )

    # Parse the arguments
    args = parser.parse_args()

    # Execute the script
    try:
        result = main(args)
        if result:
            parser.exit(result)
        parser.exit()
    except Exception as e:
        parser.error(str(e))