^:'str'和'int'异或解密的操作数类型不受支持

我尝试按如下方式解密单字节异或(按原样执行):

from binascii import unhexlify

if __name__ == "__main__":

    encoded = unhexlify("7f454c467f454c467f454c46")
    for key in range(256):
        decoded = ''.join(chr(b ^ key) for b in encoded)
        if decoded.isprintable():
            print(key, decoded)

执行时出现以下错误:

File "temp.py", line 8, in <module>
    decoded = ''.join(chr(b ^ key) for b in encoded)
File "temp.py", line 8, in <genexpr>
    decoded = ''.join(chr(b ^ key) for b in encoded)
TypeError: unsupported operand type(s) for ^: 'str' and 'int'