Creating Xor Checksum Of All Bytes In Hex String In Python
Answer : You have declared packet as the printable representation of the message: packet = '0x8d 0x1e 0x19 0x1b 0x83 0x00 0x01 0x01 0x00 0x00 0x00 0x4b 0x00 0x00' so your current message is not [0x8d, 0x1e, ..., 0x00] , but ['0', 'x', '8', 'd', ..., '0'] instead. So, first step is fixing it: packet = '0x8d 0x1e 0x19 0x1b 0x83 0x00 0x01 0x01 0x00 0x00 0x00 0x4b 0x00 0x00' packet = [chr(int(x, 16)) for x in packet.split(' ')] Or, you could consider encoding it "right" from the beginning: packet = '\x8d\x1e\x19\x1b\x83\x00\x01\x01\x00\x00\x00\x4b\x00\x00' At this point, we can xor, member by member: checksum = 0 for el in packet: checksum ^= ord(el) print checksum, hex(checksum), chr(checksum) the checksum I get is 0x59 , not 0xc2 , which means that either you have calculated the wrong one or the original message is not the one you supplied.