introduction

Halo2 configuration

We currently support Halo2 circuits in an experimental stage. To use Halo2, you need to set the adapter to halo2 in the mopro-config.toml file.

[circuit]
adapter = "halo2" # Options: circom, halo2
dir = "mopro-core/examples/halo2/fibonacci" # Directory of the circuit
name = "fibonacci"                # Name of the circuit

The dir should point to the directory where the Halo2 circuit is located. The name should be the name of the circuit.

Note that currently the Halo2 circuit must be a cargo crate, with the package name hardcoded to halo2-circuit. This is due to us swapping out the default implementation of the halo2-ciurcuit crate with the user's circuit during the build process. This is done using the build.rs script in the mopro-core crate, which changes the path to the default examples/halo2/fibonacci to $dir. This also requires the name of the package to be halo2-circuit for the substitution to work.

Additionally, the halo2-circuit crate must implement and expose three items, which you can see in the mopro-core/examples/halo2/fibonacci/src/lib.rs:

• Circuit - the struct that represents the circuit
• prove - the function that generates the proof
• verify - the function that verifies the proof

This is then used by the mopro-core crate to generate the proof and verify it.