heliaxdev/halo2

halo2

Documentation

Minimum Supported Rust Version

Requires Rust 1.60 or higher.

Minimum supported Rust version can be changed in the future, but it will be done with a minor version bump.

Controlling parallelism

halo2 currently uses rayon for parallel computation. The RAYON_NUM_THREADS environment variable can be used to set the number of threads.

You can disable rayon by disabling the "multicore" feature. Warning! Halo2 will lose access to parallelism if you disable the "multicore" feature. This will significantly degrade performance.

License

Licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

halo2's Issues

Use Poseidon sponge in Halo2 transcript in prover and out-of-circuit verifier

The Halo2 proving system needs to be modified to use the Poseidon sponge to create the proof transcript instead of Blake2 or another non-circuit friendly hash.

This requires:

• Finishing #6
• Creating a ChallengeScalar type to replace the byte Challenge255
• Creating a PoseidonTranscript which uses the Poseidon sponge and ChallengeScalar
• Handle prefixes in a better way than absorbing prefix twice (related to manual padding)
• Cleanup, e.g. merging Transcript and PoseidonTranscript to reduce redundant code
• Verify correct behavior with good tests
• Merge to some upstream

Poseidon sponge full duplex mode

The Poseidon circuit gadget and out of circuit implementation needs to support the full duplex mode in order to create Poseidon based halo 2 transcripts.

The main tasks related to this are:

• Implementing the full duplex mode in the out of circuit implementation
• Implementing the full duplex mode in the circuit gadget
• Verifying through appropriate tests that the behavior of the circuit gadget matches the out of circuit implementation
• Verifying through appropriate tests that the behavior of both match the Poseidon specification
• Adding tests for edge cases
• Handling padding in a better way than requiring manual padding
• Improving the generic quality of the code
• Merging to an upstream where it is usable

The relevant upstream issues:

• zcash#634
• zcash#629 (not a strict dependency)