Solution #

You will be given this string, cvpbPGS{arkg_gvzr_V'yy_gel_2_ebhaqf_bs_ebg13_hyLicInt}. Apply ROT13 to it and you’ll get the flag.

 1def rot13(s):
 2    ret = []
 3    for c in s:
 4        if ord("a") <= ord(c) <= ord("z"):
 5            ret.append(chr((ord(c) - ord("a") + 13) % 26 + ord("a")))
 6        elif ord("A") <= ord(c) <= ord("Z"):
 7            ret.append(chr((ord(c) - ord("A") + 13) % 26 + ord("A")))
 8        else:
 9            ret.append(c)
10    return "".join(ret)
11
12
13def main():
14    flag = "cvpbPGS{arkg_gvzr_V'yy_gel_2_ebhaqf_bs_ebg13_hyLicInt}"
15    decoded_flag = rot13(flag)
16    print(decoded_flag)
17
18
19if __name__ == "__main__":
20    main()

Acknowledgement #

Thank you, CMU security and privacy experts, for creating this challenge.