使用Cryptography Fernet解密失败：Invalid Token错误求助

问题出在加密内容的写入方式上：你把加密后的字节对象用str()转成字符串写入，这会给令牌套上b''的外壳（比如原本的b'gAAAAAB...'变成了"b'gAAAAAB...'"）。读取时再encode，得到的是b"b'gAAAAAB...'"，这根本不是合法的Fernet令牌，自然会报"invalid token"。

修正后的代码 #

from cryptography.fernet import Fernet
key = b'Sw42CeEyZCyRyct0Ly2loEga9D4iv6tF0WRiTLKVdDA='
fkey = Fernet(key)

def add():
    app = input("enter app name ").upper()
    name = input("enter account name ")
    password = input("enter account password ")
    with open("passwords2.txt", 'a') as f:
        original = "{}: {} | {} ".format(app, name, password)
        inbytes = original.encode()
        originalencrypted = fkey.encrypt(inbytes)
        # 把加密后的字节解码成utf-8字符串写入，避免b''包裹
        f.write(originalencrypted.decode('utf-8') + "\n")

def read():
    with open("passwords2.txt", 'r') as f:
        for line in f:
            # 直接把字符串转成字节后解密
            print(fkey.decrypt(line.strip().encode('utf-8')).decode())

while True:
    operation = input("would you like to read, add, or quit (q) ")
    if operation == "read":
        read()
    elif operation == "add":
        add()
    elif operation == "q" or operation == "quit":
        quit()
    else:
        print("invalid input")

关键修改点 #

• 写入时：用originalencrypted.decode('utf-8')替代str(originalencrypted)，直接把加密后的字节转成可写入的字符串
• 读取时：不需要处理多余的字符，直接line.strip().encode('utf-8')就能得到正确的加密字节令牌

内容的提问来源于stack exchange，提问作者manlearnscode