3doges2

POLI CTF Crypto Challenge: 400pts

Challenge Description:

" Wanna talk with John? Join his supersecret communication channel. Of course it's secure, it uses a brand new hipster handmade cryptocipher! Amazingly unbreakable! The party is on the:
doges.polictf.it:80
GPG key: oliphushIkDeedTarWodVenEfyockOc2

This challenge used GO's 3DES encyption scheme, CBC mode and EDE2 (important for generating the private key)

Material:

Solution:

The vulnerability in this challenge lay in the 'doge' operations used to make the private key 'super secure' before generating the final 3DES private key used to encrypt the secret plaintext.
(Python scripts for server and client linked at the bottom.)

For the solution you had to write a client to automatically generate the private key and decrypt the secret to get the flag from the server.

Stages to authenticate:

Flag:

Scripts:

SERVER