Introduction to Cryptographic Attacks

Presented at DEF CON 30 (2022), Aug. 12, 2022, 9 a.m. (240 minutes)

Using cryptography is often a subtle practice and mistakes can result in significant vulnerabilities. This workshop will cover many of these vulnerabilities which have shown up in the real world, including CVE-2020-0601. This will be a hands-on workshop where you will implement the attacks after each one is explained. I will provide a VM with Python dependencies and skeleton code included so you can focus on implementing the attack. A good way to determine if this workshop is for you is to look at the challenges at cryptopals.com and see if those look interesting, but you could use in person help understanding the attacks. While not a strict subset of those challenges, there is significant overlap. Materials: A laptop with VMWare or VirtualBox installed and capable of running a VM. Prereq: Students should be comfortable with modular arithmetic and the properties of XOR. Experience in Python or other similar language will be a plus.

Presenters:

  • Matt Cheung - Hacker
    Matt Cheung started developing his interest in cryptography during an internship in 2011. He worked on implementation of a secure multi-party protocol by adding elliptic curve support to an existing secure text pattern matching protocol. Implementation weaknesses were not a priority and this concerned Matt. This concern prompted him to learn about cryptographic attacks from Dan Boneh's crypto 1 course offered on Coursera and the Matasano/cryptopals challenges. From this experience he has given workshops at the Boston Application Security Conference, BSidesLV, DEF CON, and the Crypto and Privacy Village.

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