我写了一个简单的128-AES加密代码，它工作正常，直到我更改密钥的字符，我得到这个错误：
File "c:\Python34\Lib\encodings\cp720.py", line 21, in encode
return codecs.charmap_encode(input,self.errors,encoding_table)[0]
builtins.UnicodeEncodeError: 'charmap' codec can't encode character '\xc2' in position 2: character maps to <undefined>
我使用ord()和chr()进行字母编码。该表位于cp720.py文件中：
decoding_table = (
'\x00' # 0x00 -> CONTROL CHARACTER
'\x01' # 0x01 -> CONTROL CHARACTER
'\x02' # 0x02 -> CONTROL CHARACTER
'\x03' # 0x03 -> CONTROL CHARACTER
'\x04' # 0x04 -> CONTROL CHARACTER
'\x05' # 0x05 -> CONTROL CHARACTER
'\x06' # 0x06 -> CONTROL CHARACTER
'\x07' # 0x07 -> CONTROL CHARACTER
'\x08' # 0x08 -> CONTROL CHARACTER
'\t' # 0x09 -> CONTROL CHARACTER
'\n' # 0x0A -> CONTROL CHARACTER
'\x0b' # 0x0B -> CONTROL CHARACTER
'\x0c' # 0x0C -> CONTROL CHARACTER
'\r' # 0x0D -> CONTROL CHARACTER
'\x0e' # 0x0E -> CONTROL CHARACTER
'\x0f' # 0x0F -> CONTROL CHARACTER
'\x10' # 0x10 -> CONTROL CHARACTER
'\x11' # 0x11 -> CONTROL CHARACTER
'\x12' # 0x12 -> CONTROL CHARACTER
'\x13' # 0x13 -> CONTROL CHARACTER
'\x14' # 0x14 -> CONTROL CHARACTER
'\x15' # 0x15 -> CONTROL CHARACTER
'\x16' # 0x16 -> CONTROL CHARACTER
'\x17' # 0x17 -> CONTROL CHARACTER
'\x18' # 0x18 -> CONTROL CHARACTER
'\x19' # 0x19 -> CONTROL CHARACTER
'\x1a' # 0x1A -> CONTROL CHARACTER
'\x1b' # 0x1B -> CONTROL CHARACTER
'\x1c' # 0x1C -> CONTROL CHARACTER
'\x1d' # 0x1D -> CONTROL CHARACTER
'\x1e' # 0x1E -> CONTROL CHARACTER
'\x1f' # 0x1F -> CONTROL CHARACTER
' ' # 0x20 -> SPACE
'!' # 0x21 -> EXCLAMATION MARK