cryptography.fernet.InvalidToken: Password Manager/Generator - sqlite

Question

I am trying to build a Tkinter GUI password manager that saves the encrypted passwords on a SQLite Database; and it returns the decrypted password back when you search in the database by the website name.
Here is my script and what it returns:
import tkinter as tk
from tkinter import messagebox
import random
import pyperclip
import sqlite3
from werkzeug.security import generate_password_hash, check_password_hash
import base64
import os
from cryptography.fernet import Fernet
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
# DATABASE.
db = sqlite3.connect('user-data.db')
cursor = db.cursor()
# cursor.execute('CREATE TABLE UserData (id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, '
# 'website varchar(250) NOT NULL UNIQUE, '
# 'email varchar(250) NOT NULL, '
# 'password varchar(250) NOT NULL)')
# cursor.execute('INSERT INTO UserData VALUES(1, "amazon.co.uk", "my_email#gmail.com", "wieuiwrhfg4")')
# db.commit()
#
# key = Fernet.generate_key()
# f = Fernet(key)
# PASSWORD GENERATOR.
def generate_password():
letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u',
'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z']
numbers = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
symbols = ['!', '#', '$', '%', '&', '(', ')', '*', '+']
password_letters = [random.choice(letters) for _ in range(random.randint(8, 10))]
password_symbols = [random.choice(symbols) for _ in range(random.randint(2, 4))]
password_numbers = [random.choice(numbers) for _ in range(random.randint(2, 4))]
password_list = password_letters + password_symbols + password_numbers
random.shuffle(password_list)
password = "".join(password_list)
password_entry.insert(0, string=password)
pyperclip.copy(password)
return password
def password_enc():
salt = os.urandom(16)
kdf = PBKDF2HMAC(algorithm=hashes.SHA256(),
length=32,
salt=salt,
iterations=480000
)
key = base64.urlsafe_b64encode(kdf.derive(bytes(generate_password(), 'utf-8')))
# key = Fernet.generate_key().decode()
f = Fernet(key)
token = f.encrypt(bytes(generate_password(), 'utf-8'))
return token, f
# SAVE PASSWORD.
def save():
website = website_entry.get() # .get() fetches the current entry text.
password = password_entry.get()
# hash_salted_password = generate_password_hash(password, method='pbkdf2:sha256', salt_length=8)
# encrypted_password = f.encrypt(str.encode(password))
# encrypted_password = str.encode(password)
# key = base64.urlsafe_b64encode(kdf.derive(str.encode(password)))
# f = Fernet(key)
# token = f.encrypt(str.encode(password))
# print(token)
if len(website) == 0 or len(password) == 0:
messagebox.showinfo(title="Oops", message="Please make sure you haven't left any fields empty.")
else:
try:
cursor.execute("INSERT INTO UserData VALUES(?, ?, ?, ?)",
(None, website_entry.get(), email_entry.get(), password_enc()[0]))
db.commit()
finally:
website_entry.delete(0, tk.END) # .delete() from index 0, first char till the END.
password_entry.delete(0, tk.END)
# FIND PASSWORD.
def find_password():
website = website_entry.get()
try:
cursor.execute("SELECT * FROM UserData WHERE website=?", (website,))
result = cursor.fetchall()
print(result)
except FileNotFoundError:
messagebox.showinfo(title="Error", message="No Data File Found.")
else:
if website in result[0]:
email = result[0][1]
hashed_password = result[0][3]
# password = check_password_hash(pwhash=hashed_password, password=generate_password())
decrypted_password = password_enc()[1].decrypt(hashed_password)
# decrypted_password = save().decode()
# decrypted_password = f.decrypt(hashed_password)
messagebox.showinfo(title=website, message=f"Email: {email}\nPassword: {decrypted_password}")
else:
messagebox.showinfo(title="Error", message=f"No details for {website} exists.")
Exception in Tkinter callback
Traceback (most recent call last):
File "/Users//PycharmProjects/pythonProject/Day-24/venv/lib/python3.10/site-packages/cryptography/fernet.py", line 133, in _verify_signature
h.verify(data[-32:])
File "/Users//PycharmProjects/pythonProject/Day-24/venv/lib/python3.10/site-packages/cryptography/hazmat/primitives/hmac.py", line 72, in verify
ctx.verify(signature)
File "/Users//PycharmProjects/pythonProject/Day-24/venv/lib/python3.10/site-packages/cryptography/hazmat/backends/openssl/hmac.py", line 85, in verify
raise InvalidSignature("Signature did not match digest.")
cryptography.exceptions.InvalidSignature: Signature did not match digest.
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/tkinter/__init__.py", line 1921, in __call__
return self.func(*args)
File "/Users//PycharmProjects/pythonProject/password-manager/p_main.py", line 112, in find_password
decrypted_password = password_enc()[1].decrypt(password_enc()[0])
File "/Users//PycharmProjects/pythonProject/Day-24/venv/lib/python3.10/site-packages/cryptography/fernet.py", line 90, in decrypt
return self._decrypt_data(data, timestamp, time_info)
File "/Users//PycharmProjects/pythonProject/Day-24/venv/lib/python3.10/site-packages/cryptography/fernet.py", line 151, in _decrypt_data
self._verify_signature(data)
File "/Users//PycharmProjects/pythonProject/Day-24/venv/lib/python3.10/site-packages/cryptography/fernet.py", line 135, in _verify_signature
raise InvalidToken
cryptography.fernet.InvalidToken
The save() function works as intended, it manages to save and hashed password on the database, but when I try to call find_password() I get the following error cryptography.fernet.InvalidToken. The #commented lines of code in my script are the various ways I have tried to solve this problem.
The closest I've got to solving this issue was to be able to encrypt/save and decrypt/find the password on the same run, after re-running the program the encryption key would change, resulting in errors.