How to XOR two strings using Python?

Question

If I have:

cipher_text1 =  "3b101c091d53320c000910"
cipher_text2 = "071d154502010a04000419"

How do I XOR the two cipher texts using Python to get:

cipher_text1_XOR_cipher_text2 = "3c0d094c1f523808000d09"

Thanks

Are `cipher_text1` and `cipher_text2` the plain text or binary? — Lizhi Liu, Feb 14 '22 at 02:59
It may be useful to you: https://stackoverflow.com/questions/29408173/byte-operations-xor-in-python — Lizhi Liu, Feb 14 '22 at 03:05

score 0 · Answer 1 · answered Feb 14 '22 at 03:24

Try this out:

cipher_text1 = "3b101c091d53320c000910"
cipher_text2 = "071d154502010a04000419"

def xor_ciphers(cipher1, cipher2):
    bin1 = int(format(int(cipher1, 16), f'0{str(len(cipher1))}b'), 2)
    bin2 = int(format(int(cipher2, 16), f'0{str(len(cipher2))}b'), 2)
    return hex(bin1 ^ bin2)


print(xor_ciphers(cipher_text1, cipher_text2))

Output:

0x3c0d094c1f523808000d09

CryptoFool · Accepted Answer · 2022-02-14T06:56:19.020

Start with the int() function, which allows you to specify a base in which to interpret a string to be converted to a numeric value. The default base the function assumes is 10, but 16 works too and is what's appropriate for the strings you have. So you convert your two strings to numeric values with int(), and then perform the XOR on those values. Then, you apply the hex() function to the result convert it to a hex string. Finally, since you asked for a result without Ox at the front, you apply the appropriate slice to chop off the first two characters of what hex() returns:

cipher_text1 = "3b101c091d53320c000910"
cipher_text2 = "071d154502010a04000419"

cipher_text1_XOR_cipher_text2 = hex(int(cipher_text1, 16) ^ int(cipher_text2, 16))[2:]

print(cipher_text1_XOR_cipher_text2)

Result:

3c0d094c1f523808000d09

How to XOR two strings using Python?

2 Answers2