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Cryptography

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    $\begingroup$ The hint could be related to weak keys in DES. Or not. $\endgroup$ Commented Aug 6, 2023 at 6:33
  • $\begingroup$ I thought about that as well, I have read some articles about them and as I understood with 4 specific keys I could obtain the same ciphertext as the plaintext. I have tried passing one of the keys suggested as weak to the program and proceed to obtain the encrypted flag. I obtained some bytes, but I do not think they are equal to the flag, they seem to be just random bytes.. $\endgroup$ Commented Aug 6, 2023 at 9:13
  • $\begingroup$ I edited the question and added my current approach which makes use of the weak keys to obtain the plaintext by the ciphertext, but the problem is that when I xor it with the otp I get in phase 1 I get random bytes, and I was expecting to get the flag, is there any error in the idea or is the problem in the implementation itself according to you? $\endgroup$ Commented Aug 6, 2023 at 10:07
  • $\begingroup$ You repeatedly assert(foo). Please don't do that. Better to simply assert foo. Then a maintenance engineer won't be tricked into "refactoring" as assert(foo, "diagnostic msg"), which means something very very different from assert foo, "diagnostic msg". $\endgroup$ Commented Aug 6, 2023 at 16:11