picoCTF 2022 | rail-fence Write-up

Challenge description

A type of transposition cipher is the rail fence cipher, which is described here. Here is one such cipher encrypted using the rail fence with 4 rails. Can you decrypt it? Download the message here. Put the decoded message in the picoCTF flag format, picoCTF{decoded_message}.

Category: Cryptography

Solution

The message.txt file contains the ciphertext. Run it through an online tool to decode. Example
Note: remember to set the rails/level to 4
We should get our decoded flag immediately

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