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https://github.com/BitVM/bitvm-circom-example
https://github.com/BitVM/bitvm-circom-example
Last synced: 6 days ago
JSON representation
- Host: GitHub
- URL: https://github.com/BitVM/bitvm-circom-example
- Owner: BitVM
- Created: 2024-04-06T17:55:58.000Z (7 months ago)
- Default Branch: master
- Last Pushed: 2024-04-22T13:40:51.000Z (7 months ago)
- Last Synced: 2024-08-01T21:42:30.111Z (3 months ago)
- Language: Solidity
- Size: 24.4 KB
- Stars: 4
- Watchers: 3
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
- awesome-bitvm - BitVM Circom Example in Java
README
This repository contains an example circom circuit that is used to test the Bitcoin script for a fflonk verifier.
## Dependencies
We use circom, snarkjs, and circomlib.
- follow instructions [here](https://docs.circom.io/getting-started/installation/#installing-snarkjs) to install circom and snarkjs.
- circomlib has been included as a git submodule. One can do `git submodule update --init --remote --recursive`.
## Instructions
### Step 1: obtain the setup parameters
We use the KZG setup ceremony that Polygon Hermez has done. More information can be found [here](https://github.com/iden3/snarkjs).
```console
wget https://storage.googleapis.com/zkevm/ptau/powersOfTau28_hez_final_21.ptau
```
### Step 2: compile the circuit
We use circom to compile the circuit.
```console
circom test_circuit.circom --r1cs --wasm --sym
```
### Step 3: perform the witness generation
Then, we use the witness generator that circom creates to compute the witness.
```console
cd test_circuit_js
node generate_witness.js test_circuit.wasm ../input.json ../witness.wtns
cd ../
```
You can test if the witness is correct.
```console
snarkjs wtns check test_circuit.r1cs witness.wtns
```
### Step 4: preprocess the keys
Now, we use snarkjs to preprocess the keys, which creates the proving key file `circuit.zkey`
```console
snarkjs fflonk setup test_circuit.r1cs powersOfTau28_hez_final_21.ptau circuit.zkey
```
### Step 5: export the verification key
We can derive the verifying key out of the proving key.
```console
snarkjs zkey export verificationkey circuit.zkey verification_key.json
```
### Step 6: create the proof
We can now run the proof generation.
```console
snarkjs fflonk prove circuit.zkey witness.wtns proof.json public.json
```
For testing purposes, however, it is more common to use fixed randomness.
```console
USE_FIXED_RANDOMNESS=1 snarkjs fflonk prove circuit.zkey witness.wtns proof.json public.json
```
And if one wants to save the console output to a file, use `|& tee a.txt`.
To check if the verifier will accept this proof, do:
```console
snarkjs fflonk verify verification_key.json public.json proof.json
```
### Step 7: export the Solidity verifier contract
A very convenient feature of snarkjs is that it can generate a highly efficient and fully preprocessed Solidity smart contract that exactly represents the verifier.
```console
snarkjs zkey export solidityverifier circuit.zkey verifier.sol
```