Formal Reasoning in Coq — a Beginner's Guide

I’m currently taking the Fall 2017 iteration of 6.826, Principles of Computer Systems. This class has been offered in various forms over the years, but this iteration is quite different. It focuses on formal verification of computer systems using Coq, a language for mechanical theorem proving.

The goal of this class is to write the spec, implementation, and proofs for a formally verified RAID filesystem in Coq, then generate Haskell code from it.

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Looking Towards Summer: Concolic Execution, Fuzzy Panda, and More

It’s always bothered me that MIT or MIT Lincoln Lab didn’t submit anything to DARPA’s Cyber Grand Challenge. With all the smart people, such as my advisor, Armando Solar-Lezama, working on program analysis and formal methods (which I currently know nothing about), I would have expected that we could create a strong Cyber Reasoning System worthy of CGC.

That’s sort of what I will be working on this summer at Lincoln and probably writing my thesis on. But I’m very new to the field and have just started diving in.

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Matasano Crypto Challenges, Set 6

The last of the original crypto challenges… here we go!

Challenge 41 Implement unpadded message recovery oracle

Unpadded RSA is homomorphic, meaning that, if operations like multiplication and addition are carried out on ciphertext, it is as if the same operation were applied to the plaintext.

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Generating and Interpreting Bytecode for MITScript — Using Rust

Well, this was my first foray into the world of Rust, the systems language that is Mozilla’s precious baby. And what better way to learn this hip new language than to write an MITScript bytecode interpreter for Computer Language Engineering?

Rust was not gentle for this first-time developer. It does so much to protect you that my first attempt writing a few hundred lines of code resulted in the same number of compiler errors, and I needed a lot of help from my team to just get anything to compile. For this reason, it’s not great for iterating quickly if you aren’t very experienced already. But, I’m licking my chops at the fact that the end result will be much safer, and hopefully faster, than our classmates’ C++ compilers. This post will be about the struggles I encountered as a Rust newbie, as well as the fun of generating/interpreting MITScript bytecode.

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Matasano Crypto Challenges, Set 5

This set was surprisingly easy, actually. The book Understanding Cryptography by Paar & Pelzl is an excellent intro to the basic maths needed for crypto — namely, the group theory and number theory necessary for RSA and Diffie-Hellman.

Let’s dive in!

Challenge 33 Implement Diffie-Hellman

Diffie-Hellman is a remarkably simple algorithm for two parties to jointly compute a shared secret key that may be used, for example, as a key for symmetric encryption.

Alice and Bob agree on an integer group of prime pp, with a generator gg. gg raised to every power in 0...p1{0...p-1}, taken modp\bmod p, can produce every element of pp. Hence, it is called a “generator” of the group.

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Writing a C++ Interpreter for MITScript

Lab 2 in 6.035 was very satisfying and very fun. After creating the parser/lexer in Lab 1, we got to put our Abstract Syntax Tree to work — we created an interpreter to actually execute valid MITScript! By the end of this lab, we will be able to write arbitrarily complex programs and have them parsed and run.

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