Aptenodytes Forsteri

The flag has been encoded into string IOWJLQMAGH except prefix flag{ and suffix ‘}’, the mapping is as following.

letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
encoded = ""
for character in flag[5:-1]:
    encoded+=letters[(letters.index(character)+18)%26] #encode each character

So if we could find out the reverse mapping, we could decode the flag.

r_letters = [letters[(i+18)%26] for i in range(26)]
for c in cipher:
    a = r_letters.index(c)
    print(letters[a], end='')

By decoding the string got the flag flag{QWERTYUIOP}.

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