Overview：

The mission of DelphiusLab is to provide Web2 developers with a concise toolset to leverage the power of Web3 in their applications. The ZKWASM (ZKSNARK virtual machine that supports Web Assembly) serves as a trustless layer between rich applilcations running on WASM runtime and smart contracts on chain.

WASM (or WebAssembly) is an open standard binary code format similar to assembly. Its initial objective was to provide an alternative to java-script with improved performance for the current web ecosystem. Benefiting from its platform independence, front-end flexibility (can be compiled from the majority of languages including C, C++, assembly script, rust, etc.), good isolated runtime and speed comes closer to the speed of a native binary, its usage is arising in distributed cloud and edge computing. Recently it has become a popular binary format for users to run customized functions on AWS Lambda, Open Yurt, AZURE, etc.

The idea of ZKWASM is derived from ZKSNARK (Zero-Knowledge Succinct Non-Interactive Argument of Knowledge) which is a combination of SNARG (Succinct non-interactive arguments) and zero-knowledge proof. In general, the adoption of ZKSNARK usually requires implementing a program in arithmetic circuits or circuit-friendly languages (Pinocchio, TinyRAM, Buffet/Pequin, Geppetto, xJsnark framework, ZoKrates) that forms a barrier for existing programs to leverage it's power. An alternative approach is, instead of applying ZKSNARK on the source code, applying it on the bytecode level of a virtual machine and implementing a zksnark-backed virtual machine. In this work, we take the approach of writing the whole WASM virtual machine in ZKSNARK circuits so that existing WASM applications can benefit from ZKSNARK by simply running on the ZKWASM, without any modification. Therefore, the cloud service provider can prove to any user that the computation result is computed honestly and no private information is leaked.

Circuit Details:

https://jhc.sjtu.edu.cn/~hongfeifu/manuscriptb.pdf

Quick start with ZKWASM command line

Dependency

Make sure the following packages are installed.

clang lld

Install Instructions

git clone --recurse-submodules https://github.com/DelphinusLab/zkwasm
cargo build

Setup input:

wasm code

Runtime input:

input of wasm function and the top level function must be zkmain

Proving target:

simulation of wasm execution of target wasm bytecode with particular inputs are correct.

Command line:

Setup via WASM image:

delphinus-cli --params <PARAMS> <NAME> setup [OPTIONS] --wasm <WASM>

with OPTIONS:

    -h, --help
            Print help information

        --host <HOST_MODE>
            Specify execution host environment for the runtime [default: default] [possible values:
            default, standard]

    -k <K>
            Size of the circuit. [default: 18]

        --phantom <PHANTOM_FUNCTIONS>
            Specify phantom functions whose body will be ignored in the circuit

        --wasm <WASM>
            Path to the Wasm image

Single prove and verify:

cargo run --release -- --params <PARAMS> <NAME> prove [OPTIONS] --wasm <WASM> --output <OUTPUT>

with OPTIONS:

        --ctxin <CONTEXT_INPUT>
            Context inputs with format value:type where type=i64|bytes|bytes-packed, values can be
            separated by `,` or multiple occurrence of `--ctxin`

        --ctxout [<CONTEXT_OUTPUT>...]
            Path to context output

        --file
            Enabling the file backend for table to support enormous execution trace. It may reduce
            the speed of execution.

    -h, --help
            Print help information

    -m, --mock
            Enable mock test before proving

    -o, --output <OUTPUT>
            Path to output directory

        --private <PRIVATE_INPUT>
            Private inputs with format value:type where type=i64|bytes|bytes-packed, values can be
            separated by `,` or multiple occurrence of `--private`

        --public <PUBLIC_INPUT>
            Public inputs with format value:type where type=i64|bytes|bytes-packed, values can be
            separated by `,` or multiple occurrence of `--public`

        --wasm <WASM>
            Path to the Wasm image

cargo run --release -- --params <PARAMS> <NAME> verify --output <OUTPUT>

Batch prove and verify:

Please see zkWASM continuation batcher at https://github.com/DelphinusLab/continuation-batcher for batching proof with host circuits and verifier generation in smart contracts.

Operations Spec [WIP]

We uses z3 (https://github.com/Z3Prover/z3) to check that all operation are compiled to zkp circuits correctly.

[This is a WIP project, only sample code are provided here. Please contact [email protected] for state circuit customization and application integration.

Issue tracking:

• chore: non-feature requirements such as CI/CD, building script or work flow enhancement.
• feat: feature need, we could use feat(circuit), feat(lang), feat(CLI) to categorize features
• bug: bug report, we also could use bug(circuit), bug(lang) to categorize bugs
• doc: documents related issues.

Project Bootstrap:

• C project: There is a project template for compiling C to wasm with limited host functions (foreign circuits). (see https://github.com/DelphinusLab/zkWasm-C)
• Rust project demo: https://github.com/xgaozoyoe/zkWasm-Rust-Demo
• Assembly script demo: https://github.com/DelphinusLab/zkWasm-AssemblyScript-Demo
• Browser based project: See https://github.com/zkcrossteam/g1024/ for how to utilizing zkWASM in javascript, how to generate proofs using PAAS service and verify it on chain (contact [email protected] for details about PAAS testnet).