David Ashby on SHA256

New York - December 6, 2017


While most of us use hash functions on a daily basis, few people can say that they truly understand what’s actually going on when they call SHA2("hello world"). Even fewer can say they’ve bothered to implement the function themselves, considering every introduction to cryptography starts off with a big warning saying to never, ever implement cryptographic primitives and just use vetted libraries due to the security implications. Of course, that important warning didn’t stop me from digging into the FIPS 180-4 spec to scratch the itch to understand how exactly it works, and along the way get a much better intuition about what bitwise operators actually do, what a bit rotation is, and why hex notation actually matters.


David Ashby is a self-taught programmer and systems engineer who sometimes spends his weekends implementing hash functions in high-level languages. He also helps organize the meetup, but no nepotism was to blame for the existence of this presentation.



TwoSigma The New York Chapter would like to thank TwoSigma for helping to make this meetup possible.