6a7e8d0fb0
Summary of the design: - Tries are stored as immutable, copy-on-write trees - All trie data is stored in the `TrieData` segment. Since it's immutable, data is never modified/deleted, new versions are just appended at the end. - In order to support reverts, each context stores a pointer to the initial state trie version, plus the initial version of each storage trie. One variation which may be worth considering is storing the whole state trie as one big trie (with sub-tries for storage). Reverts would then be simpler - we'd replace a single pointer. I thought that approach might make hashing the trie a bit more complex, as the node associated with an account would be a special type of node, rather than just another leaf. Either approach seems reasonable though.
Plonky2
Plonky2 is a SNARK implementation based on techniques from PLONK and FRI. It is the successor of Plonky, which was based on PLONK and Halo.
Plonky2 is built for speed, and features a highly efficient recursive circuit. On a Macbook Pro, recursive proofs can be generated in about 170 ms.
Documentation
For more details about the Plonky2 argument system, see this writeup.
Building
Plonky2 requires a recent nightly toolchain, although we plan to transition to stable in the future.
To use a nightly toolchain for Plonky2 by default, you can run
rustup override set nightly
in the Plonky2 directory.
Running
To see recursion performance, one can run this bench, which generates a chain of three recursion proofs:
RUSTFLAGS=-Ctarget-cpu=native cargo run --release --example bench_recursion -- -vv
Jemalloc
Plonky2 prefers the Jemalloc memory allocator due to its superior performance. To use it, include jemallocator = "0.3.2" inCargo.tomland add the following lines
to your main.rs:
use jemallocator::Jemalloc;
#[global_allocator]
static GLOBAL: Jemalloc = Jemalloc;
Jemalloc is known to cause crashes when a binary compiled for x86 is run on an Apple silicon-based Mac under Rosetta 2. If you are experiencing crashes on your Apple silicon Mac, run rustc --print target-libdir. The output should contain aarch64-apple-darwin. If the output contains x86_64-apple-darwin, then you are running the Rust toolchain for x86; we recommend switching to the native ARM version.
Copyright
Plonky2 was developed by Polygon Zero (formerly Mir). While we plan to adopt an open source license, we haven't selected one yet, so all rights are reserved for the time being. Please reach out to us if you have thoughts on licensing.
Disclaimer
This code has not yet been audited, and should not be used in any production systems.