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}.

How about some hide and seek heh? Look at this image here.

How about we take you on an adventure on exploring certificate signing requests. Take a look at this CSR file here.

Can you decrypt this message? Decrypt this message using this key "CYLAB".

We found this weird message being passed around on the servers, we think we have a working decryption scheme. Download the message here. Take each number mod 37 and map it to the following character set: 0-25 is the alphabet (uppercase), 26-35 are the decimal digits, and 36 is an underscore. Wrap your decrypted message in the picoCTF flag format (i.e. picoCTF{decrypted_message})

What do the flags mean?

The one time pad can be cryptographically secure, but not when you know the key. Can you solve this? We've given you the encrypted flag, key, and a table to help UFJKXQZQUNB with the key of SOLVECRYPTO. Can you use this table to solve it?.

You will find the flag after decrypting this file. Download the encrypted flag here.