WIP: ZK Attestation Framework - by Usher Labs

Supported platforms

• Linux x86-64

Docker must operate on a compatible OS to work. Apple Silicon: Is not compatible even with --platform linux/amd64.

Installation

Docker

Build the Image

docker build . -t zkaf

Test the Image

docker run --rm -t zkaf:latest cargo --version

This should respond with something like cargo 1.77.2 (e52e36006 2024-03-26)

SSH into Image

docker run -v ./:/opt/zkaf/ -it zkaf:latest /bin/bash

Command Prefixing

To continue operating all of the circuit build and generation instructions, simply prefix the commands with:

docker run -v ./:/opt/zkaf/ -t zkaf:latest <insert zkllvm circuit command>

Base OS (Ubuntu)

Prerequisites

Dependencies:

• Python 3.10+
• Git
• Curl

On most of the modern Linux-based platforms you will already have these installed.

Install

Reference: https://github.com/NilFoundation/zkllvm-rust-template

# Install zkLLVM
sudo bash -c "echo 'deb [trusted=yes]  http://deb.nil.foundation/ubuntu/ all main' >>/etc/apt/sources.list"
sudo apt update
sudo apt install -y zkllvm proof-producer

# Install LLVM - requires llvm-symbolizer in PATH
sudo apt install llvm

# Install zkLLVM rslang-toolchain -- NOTE: Use Python3 on latest Ubuntu versions.
curl --proto '=https' --tlsv1.2 -sSf https://cdn.jsdelivr.net/gh/NilFoundation/zkllvm@master/rslang-installer.py | python3 - --channel nightly

Build

cargo +zkllvm build --release --target assigner-unknown-unknown --features=zkllvm

Tells Rust to use zkllvm libraries which uses forks of arkworks and other crypto libs for more efficient circuits.

Compiles to a .ll format, which is an intermediate LLVM assembly representation of our code.

This is used to produce the circuit and assignment table.

💡 Do not use `assert` methods from native Rust. Instead return a boolean, or some value, or `nil`.

Circuit Generation

Here we use the assigner CLI tool.

This takes two inputs:

1. the .ll assembly code
2. an input file in a JSON format, which contains input values for your circuit function.

assigner -b target/assigner-unknown-unknown/release/zkaf.ll -i inputs/example.json -t output/assignment.tbl -c output/circuit.crct -e pallas

However, the default Rust circuit logic within the zkLLVM-rust-tempate , will not compile. Changing this may indeed work.

💡 To write to an `output` directory, be sure to `mkdir` prior to the `assigner` execution

Transpile to EVM Proof Verifier

From within the output dir,

For Test Proof that is locally verified:

transpiler -m gen-test-proof -i inputs/example.json -c output/circuit.crct -t output/assignment.tbl -e pallas -o ./output/proof

Unsure what the difference here is with using:

proof-generator-multi-threaded --circuit output/circuit.crct --assignment output/assignment.tbl --proof output/proof-2/proof.bin

For EVM Verifier:

transpiler -m gen-evm-verifier -i inputs/example.json -c output/circuit.crct -t output/assignment.tbl -e pallas -o ./output/verifier

The modular_verifier.sol is the entrypoint.

Solidity files require a rewrite to use evm-placeholder-verification dependency.

pnpm use-sol-deps

Notes

Public vs Private Inputs

• Public Inputs are provided all the way through to verification on-chain.
• Private Inputs are passed only into the assignment step

Both inputs are passed as files — therefore there needs to be an automation of process creation for the ZK Prover — unless we fork the proof-market.

💡 Examples if Inputs — https://github.com/NilFoundation/zkLLVM/tree/master/examples/inputs