101 lines
2.8 KiB
Python
Executable File
101 lines
2.8 KiB
Python
Executable File
#!/usr/bin/env python3
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"""passdrill: typing drills for practicing passphrases
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"""
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import sys
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import os
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from getpass import getpass
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from hashlib import scrypt
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from base64 import b64encode, b64decode
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from typing import Sequence, Tuple
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HASH_FILENAME = 'passdrill.hash'
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HELP = 'Use -s to save passphrase hash for practice.'
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def prompt() -> str:
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print('WARNING: the passphrase WILL BE SHOWN so that you can check it!')
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confirmed = ''
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while confirmed != 'y':
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passphrase = input('Type passphrase to hash (it will be echoed): ')
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if passphrase == '' or passphrase == 'q':
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print('ERROR: the passphrase cannot be empty or "q".')
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continue
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print(f'Passphrase to be hashed -> {passphrase}')
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confirmed = input('Confirm (y/n): ').lower()
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return passphrase
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def crypto_hash(salt: bytes, passphrase: str) -> bytes:
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octets = passphrase.encode('utf-8')
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# Recommended parameters for interactive logins as of 2017:
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# N=32768, r=8 and p=1 (https://godoc.org/golang.org/x/crypto/scrypt)
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return scrypt(octets, salt=salt, n=32768, r=8, p=1, maxmem=2 ** 26)
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def build_hash(passphrase: str) -> bytes:
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salt = os.urandom(32)
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payload = crypto_hash(salt, passphrase)
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return b64encode(salt) + b':' + b64encode(payload)
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def save_hash() -> None:
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salted_hash = build_hash(prompt())
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with open(HASH_FILENAME, 'wb') as fp:
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fp.write(salted_hash)
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print(f'Passphrase hash saved to', HASH_FILENAME)
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def load_hash() -> Tuple[bytes, bytes]:
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try:
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with open(HASH_FILENAME, 'rb') as fp:
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salted_hash = fp.read()
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except FileNotFoundError:
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print('ERROR: passphrase hash file not found.', HELP)
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sys.exit(2)
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salt, stored_hash = salted_hash.split(b':')
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return b64decode(salt), b64decode(stored_hash)
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def practice() -> None:
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salt, stored_hash = load_hash()
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print('Type q to end practice.')
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turn = 0
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correct = 0
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while True:
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turn += 1
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response = getpass(f'{turn}:')
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if response == '':
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print('Type q to quit.')
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turn -= 1 # don't count this response
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continue
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elif response == 'q':
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turn -= 1 # don't count this response
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break
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if crypto_hash(salt, response) == stored_hash:
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correct += 1
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answer = 'OK'
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else:
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answer = 'wrong'
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print(f' {answer}\thits={correct}\tmisses={turn-correct}')
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if turn:
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print(f'\n{turn} turns. {correct / turn:.1%} correct.')
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def main(argv: Sequence[str]) -> None:
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if len(argv) < 2:
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practice()
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elif len(argv) == 2 and argv[1] == '-s':
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save_hash()
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else:
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print('ERROR: invalid argument.', HELP)
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sys.exit(1)
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if __name__ == '__main__':
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main(sys.argv)
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