Build a Secure Local Password Vault with Encrypted Storage in Python

import json
import os
import base64
import hashlib
from cryptography.fernet import Fernet
from getpass import getpass

class PasswordVault:
    def __init__(self, vault_file="vault.json", key_file="vault.key"):
        self.vault_file = vault_file
        self.key_file = key_file
        self.key = self._load_or_create_key()
        self.cipher = Fernet(self.key)

    def _load_or_create_key(self):
        if os.path.exists(self.key_file):
            with open(self.key_file, "rb") as f:
                return f.read()
        key = Fernet.generate_key()
        with open(self.key_file, "wb") as f:
            f.write(key)
        return key

    def _load_vault(self):
        if os.path.exists(self.vault_file):
            with open(self.vault_file, "rb") as f:
                encrypted_data = f.read()
            try:
                decrypted_data = self.cipher.decrypt(encrypted_data)
                return json.loads(decrypted_data)
            except:
                return {}
        return {}

    def _save_vault(self, vault):
        json_data = json.dumps(vault).encode()
        encrypted_data = self.cipher.encrypt(json_data)
        with open(self.vault_file, "wb") as f:
            f.write(encrypted_data)

    def add_password(self, service, username, password):
        vault = self._load_vault()
        vault[service] = {"username": username, "password": password}
        self._save_vault(vault)

    def get_password(self, service):
        vault = self._load_vault()
        return vault.get(service, None)

if __name__ == "__main__":
    vault = PasswordVault()
    vault.add_password("example.com", "user123", "SecurePass1!")
    entry = vault.get_password("example.com")
    if entry:
        print(f"Service: example.com\nUsername: {entry['username']}\nPassword: {entry['password']}")