@0xdoublesharp/sloth-vdf
v0.0.2
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Sloth Verifiable Delay Function for Javascript and Solidity 0.8
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Sloth Verifiable Delay Function
This module implements the Sloth VDF algorithm in JavaScript, TypeScript, and Soldity 0.8 for generating provable random numbers.
Install
npm install -D @0xdoublesharp/sloth-vdf
yarn add -D @0xdoublesharp/sloth-vdf
Solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;
import { SlothVDF } from '@0xdoublesharp/sloth-vdf/contracts/SlothVDF.sol';
contract RandomVDFv1 {
// large prime
uint256 public prime = 432211379112113246928842014508850435796007;
// adjust for block finality
uint256 public iterations = 1000;
// increment nonce to increase entropy
uint256 private nonce;
// address -> vdf seed
mapping(address => uint256) public seeds;
uint256 public proof;
error InvalidProof();
error AlreadyProven();
function createSeed() external payable {
// commit funds/tokens/etc here
// create a pseudo random seed as the input
uint256 _nonce = nonce++;
seeds[msg.sender] = uint256(
keccak256(abi.encodePacked(msg.sender, _nonce, block.timestamp, blockhash(block.number - 1)))
);
}
function prove(uint256 _proof) external {
if (proof != 0) revert AlreadyProven();
if (!SlothVDF.verify(_proof, seeds[msg.sender], prime, iterations)) revert InvalidProof();
// use the proof as a provable random number
proof = _proof;
}
}
JavaScript / TypeScript
describe('Sloth VDF', () => {
it('Prove', async () => {
const { sender, randomVDFv1 } = await loadFixture(fixtures);
const prime = BigInt((await randomVDFv1.prime()).toString());
const iterations = BigInt((await randomVDFv1.iterations()).toNumber());
console.log('prime', prime.toString());
console.log('iterations', iterations.toString());
const tx = await randomVDFv1.createSeed();
await tx.wait();
const seed = BigInt((await randomVDFv1.seeds(sender.address)).toString());
console.log('seed', seed.toString());
let start = Date.now();
const badproof = sloth.computeBeacon(seed, prime, BigInt(1));
console.log('compute time', Date.now() - start, 'ms', 'bad proof', badproof);
start = Date.now();
const proof = sloth.computeBeacon(seed, prime, iterations);
console.log('compute time', Date.now() - start, 'ms', 'vdf proof', proof);
await expect(randomVDFv1.prove(badproof)).to.be.revertedWithCustomError(randomVDFv1, 'InvalidProof');
await expect(randomVDFv1.prove(proof)).to.not.be.reverted;
await expect(randomVDFv1.prove(proof)).to.be.revertedWithCustomError(randomVDFv1, 'AlreadyProven');
});
});