G0cwf6XJ

1import os
2import base64
3import getpass
4import cryptography.exceptions
5from cryptography.fernet import Fernet
6from cryptography.hazmat.backends import default_backend
7from cryptography.hazmat.primitives import hashes
8from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
9
10def generate_key():
11    # ask user for passphrase
12    passphrase_provided = getpass.getpass(prompt=f'Enter passphrase: ')
13    passphrase = passphrase_provided.encode()
14    # salt generated with os.urandom(16) if not exists
15    if not os.path.exists('salt'):
16        salt = os.urandom(16)
17    else:
18        with open('salt', 'rb') as f:
19            salt = f.read()    
20    kdf = PBKDF2HMAC(
21        algorithm=hashes.SHA512_256,
22        length=32,
23        salt=salt,
24        iterations=100000,
25        backend=default_backend()
26    )
27    with open('salt', 'wb') as f:
28        f.write(salt)
29    key = base64.urlsafe_b64encode(kdf.derive(passphrase))
30    return key
31
32def create_encrypted_file(key, file_name):
33    # ask user for api key
34    api_key = getpass.getpass(prompt=f'Enter your API key: ').encode()
35    fernet = Fernet(key)
36    encrypted = fernet.encrypt(api_key)
37    # save encrypted api_key as file
38    with open(file_name, 'wb') as f:
39        f.write(encrypted)
40
41def read_from_decrypted_file(key, file_name):
42    # open encrypted file
43    with open(file_name, 'rb') as f:
44        data = f.read()
45    fernet = Fernet(key)
46    try:        
47        decrypted = fernet.decrypt(data)
48        message = decrypted.decode()
49        return message
50    except cryptography.fernet.InvalidToken:
51        print(f'Entered passphrase not valid!')
52
53def main():
54    key = generate_key()
55    file_name = 'credentials'
56    if not os.path.exists(file_name):
57        create_encrypted_file(key, file_name) 
58    elif os.path.exists(file_name):   
59        api_key = read_from_decrypted_file(key, file_name)
60        if api_key:
61            print(api_key)    
62
63
64if __name__ == '__main__':
65    main()