@zkporpoise/node-utilities

🐬 PORPOISE Network Node Utilities

This is a super-simple typescript implementation of the functions needed to generate survey roots and prediction commitments for PORPOISE that are compatible with the PORPOISE oracle contracts. This package was designed to have no external dependences.

See the PORPOISE survey commitment protocol for more information.

Installation

npm install --save-dev @zkporpoise/node-utilities

Import

import {
  ethHexString,
  padArrayToPowerOfTwo,
  mapBigIntTo256BitNumber,
  computeMerkleRoot,
  convertProofToHex,
} from "@zkporpoise/node-utilities"

Methods

• computeMerkleRoot(leafs: Buffer[], proof: Buffer[], tracker: number): takes output of padArrayToPowerOfTwo for leafs, an empty array, and the index of the leaf for which the proof is needed and returns an array containing the proof array, Merkle root, and root index. The proof and root can be used for registering and resolving survey on the PORPOISE oracle.

• padArrayToPowerOfTwo(arr: string[], paddingValue: string): given an array of string elements representing a PORPOISE survey, returns sha256-hashed leaf values. Note, that leafs must be given in the order 🐬, ⏰, 🔮, 🗳️1, ... Additionally, the deadline value (⏰) is encoded as 'hex' while all other inputs are 'binary' encoded.

• mapBigIntTo256BitNumber(bigIntValue: bigint): Converts a BigInt into a hex string so that hashes computed off-chain will match hashes computed on-chain for integers.

• predictionCommitment(salt: string, prediction: string, surveyRoot: Buffer): Buffer: Used to calculate survey commitments from end-users.

• ethHexString(muBuffer: Buffer): returns a 0x${string} type needed for viem

• convertProofToHex: converts a Buffer array and Buffer and converts to 0x${string} types for use with

Example

    it("Register a survey only once.", async function () {
      const { porpacle, owner } = await loadFixture(deployPorpacle);

      const dolphin: string = "When Moon?";
      const alarmclock: number = new Date().getTime() + 86400000;
      const hexAlarmClock: string = mapBigIntTo256BitNumber(BigInt(alarmclock));
      const oracle: string = "0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266";
      const option1: string = "Soon";
      const option2: string = "NGMI";

      // the order of the array elements is important, pad values MUST be `0` string
      const paddedComponents: Buffer[] = padArrayToPowerOfTwo([dolphin, hexAlarmClock, oracle, option1, option2], '0');

      const bufferMerkleProof: [Buffer, Buffer[], number] = computeMerkleRoot(paddedComponents, [], 1);
      const stringMerkleProof: [`0x${string}`[], `0x${string}`] = convertProofToHex(bufferMerkleProof[1], bufferMerkleProof[0]);
      const proof: `0x${string}`[] = stringMerkleProof[0];
      const root: `0x${string}` = stringMerkleProof[1];

      await porpacle.write.registerSurvey([proof, root, BigInt(alarmclock)]);
      const surveyTimeouts: bigint = await porpacle.read.surveyTimeouts([root]);
      expect(surveyTimeouts).to.equal(BigInt(alarmclock));
      await expect(porpacle.write.registerSurvey([proof, root, BigInt(alarmclock)])).to.be.rejectedWith("Survey already registered");
    });