Favourite byte

Description

For the next few challenges, you'll use what you've just learned to solve some more XOR puzzles. I've hidden some data using XOR with a single byte, but that byte is a secret. Don't forget to decode from hex first. 73626960647f6b206821204f21254f7d694f7624662065622127234f726927756d

Some of my Favourite Things

We are told the data was XORed with a single byte, which is 8 bits. This means we can brute-force all possible bytes, from 00000000 to 11111111 and XOR it with the hex until we get what looks like a flag!

from pwn import xor

HEX = "73626960647f6b206821204f21254f7d694f7624662065622127234f726927756d"

byteString = bytes.fromhex(HEX)
print(byteString)

# 2 ^ 8 = 256
# A byte can represent numbers up to 256
for i in range(256):
    # Get a byte and XOR with the byte string
    xorString = xor(byteString, i)
    print(xorString)

We can find the flag

Flag

crypto{0x10_15_my_f4v0ur173_by7e}