acvm-backend-plonky2

This is an open source backend for the ACIR standard as implemented in the Noir programming languaje, written in Rust.

For the setup, run make on the root directory. This will do the following:

For now, until the corresponding PRs are made in the Plonky2 and the Noir repositories, the command will clone these repositories inside the project root.

• https://github.com/brweisz/noir
• https://github.com/brweisz/plonky2

Those are forks of the official Noir and Plonky2 repositories respectively, with a couple modifications. The resulting project tree must therefore look like:

plonky-2-backend-for-acir
|_ noir
|_ noir_example
|_ plonky2
|_ plonky2-backend
|_ Makefile

Then it'll build noir and plonky2. The latter with the nightly toolchain. Lastly, it'll build the custom plonky2 backend.

Manual testing

For some manual testing, the workflow is as follows: in the noir_example folder there's a Noir project. In the noir_example/src/main.nr file you can write the main function of any noir program you want to prove.
Run make run_noir_example from the root directory. The following explanation is similar to the official Noir docs, but using the custom plonky2 backend instead of barretenberg, and it's what the command will execute.

1. From the noir_example directory run:

• ../noir/target/debug/nargo execute witness. This will execute the noir program through the nargo acvm, generating:
  • The ACIR circuit in target/noir_example.json
  • The witness in target/witness-name.gz

2. From the plonky2-backend directory run:

• ./target/debug/plonky2-backend prove -c ../noir_example/target/noir_example.json -w ../noir_example/target/witness -o ../noir_example/proof. This will create a Plonky2 proof in ../noir_example/proof.
• ./target/debug/plonky2-backend write_vk -b ../noir_example/target/noir_example.json -o ../noir_example/target/vk. This will create the verification key in ../noir_example/target/vk
• ./target/debug/plonky2-backend verify -k ../noir_example/target/vk -p ../noir_example/proof. This will verify the Plonky2 proof. An empty output is sign of verification success.

Running some predefined examples

If you want to try out some Noir examples, execute the python script run_examples.py with the name of the example as the only parameter from the plonky2-backend directory:

• basic_if
• fibonacci
• basic_div

Contact Us

Feel free to join our telegram group for suggestions, report bugs or any question you might have! https://t.me/+HeUDkQPX_w0yMDQx

Things already implemented in this version

The Plonky2 backend for ACIR is still in a development phase, so there are some features that will be implemented in the next months. As for now, this is the roadmap:

• AssertZero Opcode ✓
• MemoryInit Opcode ✓
• MemoryOp Opcode ✓
• BrilligCall Opcode ✓
• BlackBoxFunction ✓
  • RANGE (up to 33 bits) ✓
  • XOR ✓
  • AND ✓
  • SHA256 ✓
  • EcdsaSecp256k1 ✓