Bao: Fastest General-Purpose Cryptographic Tree Hash ⚡

This is a talk I gave at the Rust NYC meetup on November 27, 2018.

UPDATE in 2020: The Bao project at the time of this talk was two things, a custom tree hashing mode based on BLAKE2, and an implementation of verified streaming based on that tree mode. In the year after I gave this talk, the tree mode evolved into BLAKE3, which we released on January 9, 2020. The current version of Bao no longer defines a tree mode of its own, but instead implements verified streaming on top of BLAKE3. That said, the Bao hash described in this talk is very similar to BLAKE3 + Bao today, and this talk is still useful for understanding how it all works.

Project: https://github.com/oconnor663/bao
Slides: https://jacko.io/bao_presentation/presentation.html
Event URL: https://www.meetup.com/Rust-NYC/events/256499782

00:00 Introduction
01:30 What is a hash function?
03:48 Speed demo
05:43 What is a tree hash?
08:07 Streaming
12:36 Barney the Demosaur
20:51 Parallelism in Rust
25:50 SIMD
35:20 Cryptographic security
43:08 Monster hardware demo
45:06 Q&A
47:37 Monster hardware demo with htop
48:21 Rest of the Q&A