david wong

Hey! I'm David, cofounder of zkSecurity and the author of the Real-World Cryptography book. I was previously a crypto architect at O(1) Labs (working on the Mina cryptocurrency), before that I was the security lead for Diem (formerly Libra) at Novi (Facebook), and a security consultant for the Cryptography Services of NCC Group. This is my blog about cryptography and security and other related topics that I find interesting.

How does PLONK work? Part 11: Our final protocol! (Without the copy constraints) posted August 2021

In this eleventh video, I go back to the PLONK protocol and finally explain how it works with polynomial commitments. This version of the protocol is not finished, as it doesn't have zero-knowledgeness (the polynomial evaluations leak information about the polynomials) and the wiring (or copy constraint) has not been enforced (e.g. the output wire of this gate should be the left wire of this other gate). In the next video, I will explain how copy constraints can be enforced via the PLONK permutation argument.

Stay tuned for part 12... Check the full series here.

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How does PLONK work? Part 8: A polynomial dance posted August 2021

In this eighth video, I explain how the prover and the verifier can perform a "polynomial dance" in order to construct the circuit polynomial $f$. The principle is simple: the prover doesn't want to leak information about the private inputs and the intermediary values in the circuit, and the verifier doesn't want to give the prover too much freedom in the way they construct the circuit polynomial $f$.

Part 9 is here. Check the full series here.

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