cryptography, security, and random thoughts

Hey! I'm David, cofounder of zkSecurity and author of Real-World Cryptography.

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I'm also an advisor at Archetype. I was previously a cryptography architect of Mina at O(1) Labs, the security lead for Libra/Diem at Facebook, and a security engineer at the Cryptography Services of NCC Group. Welcome to my blog about cryptography, security, and other related topics.

“Cryptologie” is the French spelling of “cryptology.”

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encryption with a one letter XOR? Really?

2015-04-04 blog

So there is this app that encrypts your data on your mobile, in case it ends up in the wrong hands. Sounds good. And then there is this guy who took a look at it and figured out the data was just XORed with a 128bit keys consisting of only 4s. If the data is longer than 128bits? Let’s not encrypt it!

I don’t know how legit it is, especially considering how easy it is to just write aes(something) but here you go

elsewhere

book Real-World Cryptography Applied cryptography, from Manning. podcast Two And A Half Coins Crypto, banking & distributed systems. youtube Cryptography videos Concepts & security, explained.

encryption with a one letter XOR? Really?

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