title: Verify date: 2025-01-14 author: Nicos draft: false tags:

Description

People keep trying to trick my players with imitation flags. I want to make sure they get the real thing! I’m going to provide the SHA-256 hash and a decrypt script to help you know that my flags are legitimate.

Additional details will be available after launching your challenge instance.

Additional details:

  • ssh into the launched instance
 ssh -p 53041 ctf-player@rhea.picoctf.net
  • Using the password 1ad5be0d. Accept the fingerprint with yes, and ls once connected to begin. Remember, in a shell, passwords are hidden!
    • Checksum: 5848768e56185707f76c1d74f34f4e03fb0573ecc1ca7b11238007226654bcda
  • To decrypt the file once you’ve verified the hash, run ./decrypt.sh files/<file>.

Solution

  • Running to generate hashes for each file and grep with the checksum you were provided to get the file whose checksum matches the one given earlier.
sha256sum ./files/*
  • Next is to run the decrypt script on the files that you’ve acquired on the earlier step in order to get the flag.
./decrypt.sh 8eee7195
picoCTF{trust_but_verify_8eee7195}

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