simple_crypto.py

#usr/bin/python

#Faid Mohammed Amine 
#Fb : piratuer


### [Crypto] ASIS Finals 2017 - Simple Crypto

def xor_str(x, y):
    if len(x) > len(y):
        return ''.join([chr(ord(z) ^ ord(p)) for (z, p) in zip(x[:len(y)], y)])
    else:
        return ''.join([chr(ord(z) ^ ord(p)) for (z, p) in zip(x, y[:len(x)])])


KEY = 'musZTXmxV58UdwiKt8Tp'.encode("hex")

encrypted = open("flag.enc", "r")
cnt = encrypted.read()
encrypted.close()


decrypted = xor_str(KEY * (len(cnt) // len(KEY) + 1), cnt).decode("hex")

output = open("flag", "w")
output.write(decrypted)
output.close()