CTF  1

Goal:
The user needs to understand that someone played with the values of the image and then open it in a hex editor.

After you opened it in hex editor of some sort, you need to realize that there are numbered words and the last one contains the flag.

Implementation:

 

CTF 2

Goal:

The user gets an EXE file that acts as a dove massage delivery system which asks him to insert a dove name and a dove secret key.
after the user inserted the name and the key the system will encode the flag using the secret key and print it to the user, the user needs to understand that this is the key and that the cipher is a Vigenère cipher and decode the massage online.

Implementation: