import os
from cryptography.fernet import Fernet

def generate_and_save_key(key_file_path):
    # 生成对称密钥
    key = Fernet.generate_key()
    
    # 将密钥保存到文件中
    with open(key_file_path, 'wb') as key_file:
        key_file.write(key)

    return key

def encrypt_file(file_path, key):
    with open(file_path, 'rb') as file:
        plaintext = file.read()

    cipher_suite = Fernet(key)
    cipher_text = cipher_suite.encrypt(plaintext)

    with open(file_path + '.encrypted', 'wb') as encrypted_file:
        encrypted_file.write(cipher_text)