challenge.txt

291c1a1654081652063145303b0d53192d1b0b333d227e7f26273d5b07060f0e4e4900494e0e0f06075b3d27267f7e223d330b1b2d19530d3b3045310652160854161a1c29

ctf_xor.py

from itertools import cycle, izip
def XOR(message, key):
    return ''.join(chr(ord(c)^ord(k)) for c,k in izip(message, cycle(key)))

from xorsecret import themessage

reversed_message = themessage[::-1]
assert(themessage.count('ninja') > 0)
print XOR(themessage, reversed_message).encode('hex')
#ipython ctf_xor.py > thechallenge.txt