CRYSTALS-Kyber & Man in the Middle

This is my project for the Cryptography teaching at SSRI (computer systems and networks security) at Università Statale degli Studi di Milano, Italy.

Questo è il progetto per il corso di Crittografia a Sicurezza dei Sistemi e delle Reti Informatiche all'Università Statale di Milano.

What is this?

An implementation of CRYSTALS-Kyber

This is an implementation of a (reduced) version of the Kyber Key Encapsulation Mechanism, winner of the NIST competition for Post-Quantum Cryptography Standards.

It simulates a scenario where two players want to use AES but need to agree on common keys.

A demonstration of Man in the Middle attacks against the basic KEM protocol

It also demonstrates how the basic Kyber.KEM protocol can be vulnerable to a Man in the Middle attack.

The screenshot below shows two things that are possible in this scenario:

1. to understand the content of secrets messages
2. to edit those messages

Where to learn more about it?

You can look at the slideshow under ./slideshow. It also has a bibliography section with the papers and articles that inspired this work.

How to try it?

Prerequisites: you need to have docker installed.

Build and exec:

git clone https://github.com/S-Mancl/small-crystals-kyber-man-in-the-middle
cd small-crystals-kyber-man-in-the-middle/code
make build
make up

After the terminals open on the three nodes you can start the clients (on Alderaan and Tatooine) with

python3 lightknife_client.py

And the server (on Deathstar) with:

python3 lightknife_server.py [--evil]

Use --evil if you want to intercept the messages and change them.

Commands:

• vim like bindings: :q,:quit are available in command mode
• in command mode type i to enter insert mode, write your message then enter to send it
• in command mode use :connect to perform the key encapsulation protocol
• in command mode use :r to reload the list of messages with eventual new ones.

Close:

make down
make clean