passcheck.py

"""
Checks if a password is pwned using the https://haveibeenpwned.com/ API
Usage: python passcheck.py password
"""

import argparse
import hashlib
import urllib.request

URL = 'https://api.pwnedpasswords.com/range/'

def main(password):
    hashobj = hashlib.sha1(password.encode('utf-8'))
    hexdigest = hashobj.hexdigest().upper()
    print('SHA-1 hash: {}'.format(hexdigest,))
    resp = urllib.request.urlopen(URL + hexdigest[:5]).read().decode()
    matches = dict(match.split(':') for match in resp.splitlines())
    count = matches.get(hexdigest[5:])
    if count is None:
        print('Good news — no pwnage found!')
    else:
        print('Oh no — pwned! This password has been seen {:,} times before'.format(int(count)))


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('password')
    args = parser.parse_args()
    main(args.password)