Awesome
zkUtil
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A tool to work with zkSNARK circuits generated by circom compiler. Based on circom import code by @kobigurk
The generated keys are currently incompatible with upstream Websnark and require using a custom fork
Usage examples:
# Getting help
> zkutil --help
zkutil
A tool to work with SNARK circuits generated by circom
USAGE:
zkutil <SUBCOMMAND>
FLAGS:
-h, --help Prints help information
-V, --version Prints version information
SUBCOMMANDS:
export-keys Export proving and verifying keys compatible with snarkjs/websnark
generate-verifier Generate verifier smart contract
help Prints this message or the help of the given subcommand(s)
prove Generate a SNARK proof
setup Generate trusted setup parameters
verify Verify a SNARK proof
# Getting help for a subcommand
> zkutil prove --help
zkutil-prove
Generate a SNARK proof
USAGE:
zkutil prove [OPTIONS]
FLAGS:
-h, --help Prints help information
-V, --version Prints version information
OPTIONS:
-c, --circuit <circuit> Circuit R1CS or JSON file [default: circuit.r1cs]
-p, --params <params> Snark trusted setup parameters file [default: params.bin]
-r, --proof <proof> Output file for proof JSON [default: proof.json]
-i, --public <public> Output file for public inputs JSON [default: public.json]
-w, --witness <witness> Witness JSON file [default: witness.json]
# Suppose we have circuit file and a sample inputs
> ls
circuit.circom input.json
# Compile the circuit
> circom -rw circuit.circom
Constraints: 10000
Constraints: 20000
Constraints: 30000
Constraints: 40000
Constraints: 50000
# Generate a local trusted setup
> zkutil setup
Loading circuit...
Generating trusted setup parameters...
Has generated 28296 points
Writing to file...
Done!
# Calculate witness from the input.json
# At the moment we still need to calculate witness using snarkjs
> snarkjs calculatewitness
# Generate a snark proof
> zkutil prove
Loading circuit...
Proving...
Saved proof.json and public.json
# Verify the proof
> zkutil verify
Proof is correct
# Generate a solidity verifier contract
> zkutil generate-verifier
Created verifier.sol
# Export keys to snarkjs/websnark compatible format
> zkutil export-keys
Exporting params.bin...
Created proving_key.json and verification_key.json
# Verify the same proof with snarkjs
> snarkjs verify
OK
# Here's a list of files that we have after this
> ls
circuit.circom circuit.r1cs circuit.wasm input.json params.bin proof.json public.json Verifier.sol proving_key.json verifying_key.json witness.json
Also see test.sh
for example
Installation
Install Rust
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
Install zkutil globally
cargo install zkutil
# Make sure `~/.cargo/bin` is in $PATH (should be added automatically during Rust installation)
Or alternatively you can compile and run it instead:
git clone https://github.com/poma/zkutil
cd zkutil
cargo run --release -- prove --help