feat: add support for vrf

package.json

@@ -56,9 +56,11 @@
   "homepage": "https://github.com/redstone-finance/redstone-smartweave#readme",
   "dependencies": {
     "@assemblyscript/loader": "^0.19.23",
+    "@idena/vrf-js": "^1.0.1",
     "archiver": "^5.3.0",
     "arweave": "1.10.23",
     "bignumber.js": "^9.0.1",
+    "elliptic": "^6.5.4",
     "fast-copy": "^2.1.1",
     "knex": "^0.95.14",
     "lodash": "^4.17.21",

src/__tests__/integration/basic/vrf.test.ts

@@ -0,0 +1,191 @@
+import fs from 'fs';
+
+import ArLocal from 'arlocal';
+import Arweave from 'arweave';
+import { JWKInterface } from 'arweave/node/lib/wallet';
+import {
+  ArweaveGatewayInteractionsLoader,
+  EvaluationOptions,
+  GQLEdgeInterface,
+  InteractionsLoader,
+  LexicographicalInteractionsSorter,
+  LoggerFactory,
+  PstContract,
+  PstState,
+  SmartWeave,
+  SmartWeaveNodeFactory
+} from '@smartweave';
+import path from 'path';
+import { addFunds, mineBlock } from '../_helpers';
+import { Evaluate } from '@idena/vrf-js';
+import elliptic from 'elliptic';
+
+const EC = new elliptic.ec('secp256k1');
+const key = EC.genKeyPair();
+const pubKeyS = key.getPublic(true, 'hex');
+
+const useWrongIndex = [];
+const useWrongProof = [];
+
+describe('Testing the Profit Sharing Token', () => {
+  let contractSrc: string;
+
+  let wallet: JWKInterface;
+  let walletAddress: string;
+
+  let initialState: PstState;
+
+  let arweave: Arweave;
+  let arlocal: ArLocal;
+  let smartweave: SmartWeave;
+  let pst: PstContract;
+  let loader: InteractionsLoader;
+
+  beforeAll(async () => {
+    // note: each tests suit (i.e. file with tests that Jest is running concurrently
+    // with another files has to have ArLocal set to a different port!)
+    arlocal = new ArLocal(1823, false);
+    await arlocal.start();
+
+    arweave = Arweave.init({
+      host: 'localhost',
+      port: 1823,
+      protocol: 'http'
+    });
+
+    loader = new VrfDecorator(arweave);
+    LoggerFactory.INST.logLevel('error');
+
+    smartweave = SmartWeaveNodeFactory.memCachedBased(arweave)
+      .useArweaveGateway()
+      .setInteractionsLoader(loader)
+      .build();
+
+    wallet = await arweave.wallets.generate();
+    await addFunds(arweave, wallet);
+    walletAddress = await arweave.wallets.jwkToAddress(wallet);
+
+    contractSrc = fs.readFileSync(path.join(__dirname, '../data/token-pst.js'), 'utf8');
+    const stateFromFile: PstState = JSON.parse(fs.readFileSync(path.join(__dirname, '../data/token-pst.json'), 'utf8'));
+
+    initialState = {
+      ...stateFromFile,
+      ...{
+        owner: walletAddress,
+        balances: {
+          ...stateFromFile.balances,
+          [walletAddress]: 555669
+        }
+      }
+    };
+
+    const contractTxId = await smartweave.createContract.deploy({
+      wallet,
+      initState: JSON.stringify(initialState),
+      src: contractSrc
+    });
+
+    // connecting to the PST contract
+    pst = smartweave.pst(contractTxId);
+
+    // connecting wallet to the PST contract
+    pst.connect(wallet);
+
+    await mineBlock(arweave);
+  });
+
+  afterAll(async () => {
+    await arlocal.stop();
+  });
+
+  it('should properly return random numbers', async () => {
+    await pst.writeInteraction({
+      function: 'vrf'
+    });
+    await mineBlock(arweave);
+    const result = await pst.readState();
+    const lastTxId = Object.keys(result.validity).pop();
+    const vrf = (result.state as any).vrf[lastTxId];
+
+    console.log(vrf);
+
+    expect(vrf).not.toBeUndefined();
+    expect(vrf['random_6_1'] == vrf['random_6_2']).toBe(true);
+    expect(vrf['random_6_2'] == vrf['random_6_3']).toBe(true);
+    expect(vrf['random_12_1'] == vrf['random_12_2']).toBe(true);
+    expect(vrf['random_12_2'] == vrf['random_12_3']).toBe(true);
+    expect(vrf['random_46_1'] == vrf['random_46_2']).toBe(true);
+    expect(vrf['random_46_2'] == vrf['random_46_3']).toBe(true);
+    expect(vrf['random_99_1'] == vrf['random_99_2']).toBe(true);
+    expect(vrf['random_99_2'] == vrf['random_99_3']).toBe(true);
+  });
+
+  it('should throw if random cannot be verified', async () => {
+    const txId = await pst.writeInteraction({
+      function: 'vrf'
+    });
+    await mineBlock(arweave);
+    useWrongIndex.push(txId);
+    await expect(pst.readState()).rejects.toThrow('Vrf verification failed.');
+    useWrongIndex.pop();
+
+    const txId2 = await pst.writeInteraction({
+      function: 'vrf'
+    });
+    await mineBlock(arweave);
+    useWrongProof.push(txId2);
+    await expect(pst.readState()).rejects.toThrow('Vrf verification failed.');
+    useWrongProof.pop();
+  });
+});
+
+class VrfDecorator extends ArweaveGatewayInteractionsLoader {
+  constructor(protected readonly arweave: Arweave) {
+    super(arweave);
+  }
+
+  async load(
+    contractId: string,
+    fromBlockHeight: number,
+    toBlockHeight: number,
+    evaluationOptions: EvaluationOptions
+  ): Promise<GQLEdgeInterface[]> {
+    const result = await super.load(contractId, fromBlockHeight, toBlockHeight, evaluationOptions);
+    const arUtils = this.arweave.utils;
+
+    const sorter = new LexicographicalInteractionsSorter(this.arweave);
+
+    for (const r of result) {
+      r.node.sortKey = await sorter.createSortKey(r.node.block.id, r.node.id, r.node.block.height);
+      const data = arUtils.stringToBuffer(r.node.sortKey);
+      const [index, proof] = Evaluate(key.getPrivate().toArray(), data);
+      r.node.vrf = {
+        index: useWrongIndex.includes(r.node.id)
+          ? arUtils.bufferTob64Url(Uint8Array.of(1, 2, 3))
+          : arUtils.bufferTob64Url(index),
+        proof: useWrongProof.includes(r.node.id)
+          ? 'pK5HGnXo_rJkZPJorIX7TBCAEikcemL2DgJaPB3Pfm2D6tZUdK9mDuBSRUkcHUDNnrO02O0-ogq1e32JVEuVvgR4i5YFa-UV9MEoHgHg4yv0e318WNfzNWPc9rlte7P7RoO57idHu5SSkm7Qj0f4pBjUR7lWODVKBYp9fEJ-PObZ'
+          : arUtils.bufferTob64Url(proof),
+        bigint: bufToBn(index).toString(),
+        pubkey: pubKeyS
+      };
+    }
+
+    return result;
+  }
+}
+
+function bufToBn(buf) {
+  const hex = [];
+  const u8 = Uint8Array.from(buf);
+
+  u8.forEach(function (i) {
+    let h = i.toString(16);
+    if (h.length % 2) {
+      h = '0' + h;
+    }
+    hex.push(h);
+  });
+
+  return BigInt('0x' + hex.join(''));
+}

src/__tests__/integration/data/token-pst.js

@@ -34,7 +34,7 @@ export function handle(state, action) {
       balances[target] = qty;
     }
 
-    return { state };
+    return {state};
   }
 
   if (input.function === 'balance') {
@@ -49,7 +49,36 @@ export function handle(state, action) {
       throw new ContractError('Cannot get balance, target does not exist');
     }
 
-    return { result: { target, ticker, balance: balances[target] } };
+    return {result: {target, ticker, balance: balances[target]}};
+  }
+
+  if (input.function === 'vrf') {
+    if (!state.vrf) {
+      state.vrf = {};
+    }
+
+    state.vrf[SmartWeave.transaction.id] = {
+      vrf: SmartWeave.vrf.data,
+      value: SmartWeave.vrf.value,
+
+      random_6_1: SmartWeave.vrf.randomInt(6),
+      random_6_2: SmartWeave.vrf.randomInt(6),
+      random_6_3: SmartWeave.vrf.randomInt(6),
+
+      random_12_1: SmartWeave.vrf.randomInt(12),
+      random_12_2: SmartWeave.vrf.randomInt(12),
+      random_12_3: SmartWeave.vrf.randomInt(12),
+
+      random_46_1: SmartWeave.vrf.randomInt(46),
+      random_46_2: SmartWeave.vrf.randomInt(46),
+      random_46_3: SmartWeave.vrf.randomInt(46),
+
+      random_99_1: SmartWeave.vrf.randomInt(99),
+      random_99_2: SmartWeave.vrf.randomInt(99),
+      random_99_3: SmartWeave.vrf.randomInt(99),
+    }
+
+    return {state};
   }
 
   if (input.function === 'evolve' && canEvolve) {
@@ -59,7 +88,7 @@ export function handle(state, action) {
 
     state.evolve = input.value;
 
-    return { state };
+    return {state};
   }
 
   throw new ContractError(`No function supplied or function not recognised: "${input.function}"`);

src/contract/Contract.ts

@@ -144,13 +144,17 @@ export interface Contract<State = unknown> {
   /**
    * Creates a new "interaction" transaction using RedStone Sequencer - this, with combination with
    * RedStone Gateway, gives instant transaction availability and finality guaranteed by Bundlr.
-   *
    * @param input -  new input to the contract that will be assigned with this interactions transaction
-   * @param tags - additional tags that can be attached to the newly created interaction transaction
+   * @param options
-   * @param transfer - additional {@link ArTransfer} than can be attached to the interaction transaction
-   * @param strict - transaction will be posted on Arweave only if the dry-run of the input result is "ok"
    */
-  bundleInteraction<Input = unknown>(input: Input, tags?: Tags, strict?: boolean): Promise<any | null>;
+  bundleInteraction<Input = unknown>(
+    input: Input,
+    options: {
+      tags?: Tags;
+      strict?: boolean;
+      vrf?: boolean;
+    }
+  ): Promise<any | null>;
 
   /**
    * Returns the full call tree report the last

src/contract/HandlerBasedContract.ts

@@ -36,6 +36,7 @@ import { NetworkInfoInterface } from 'arweave/node/network';
 import stringify from 'safe-stable-stringify';
 import * as crypto from 'crypto';
 import Transaction from 'arweave/node/lib/transaction';
+import { options } from 'tsconfig-paths/lib/options';
 
 /**
  * An implementation of {@link Contract} that is backwards compatible with current style
@@ -226,12 +227,19 @@ export class HandlerBasedContract<State> implements Contract<State> {
     return interactionTx.id;
   }
 
-  async bundleInteraction<Input>(input: Input, tags: Tags = [], strict = false): Promise<any | null> {
+  async bundleInteraction<Input>(
+    input: Input,
+    options: {
+      tags: [];
+      strict: false;
+      vrf: false;
+    }
+  ): Promise<any | null> {
     this.logger.info('Bundle interaction input', input);
     if (!this.signer) {
       throw new Error("Wallet not connected. Use 'connect' method first.");
     }
-    const interactionTx = await this.createInteraction(input, tags, emptyTransfer, strict);
+    const interactionTx = await this.createInteraction(input, options.tags, emptyTransfer, options.strict, options.vrf);
 
     const response = await fetch(`${this._evaluationOptions.bundlerUrl}gateway/sequencer/register`, {
       method: 'POST',
@@ -264,7 +272,8 @@ export class HandlerBasedContract<State> implements Contract<State> {
     input: Input,
     tags: { name: string; value: string }[],
     transfer: ArTransfer,
-    strict: boolean
+    strict: boolean,
+    vrf = false
   ) {
     if (this._evaluationOptions.internalWrites) {
       // Call contract and verify if there are any internal writes:
@@ -299,6 +308,13 @@ export class HandlerBasedContract<State> implements Contract<State> {
       }
     }
 
+    if (vrf) {
+      tags.push({
+        name: SmartWeaveTags.REQUEST_VRF,
+        value: 'true'
+      });
+    }
+
     const interactionTx = await createTx(
       this.smartweave.arweave,
       this.signer,

src/core/SmartWeaveTags.ts

@@ -15,5 +15,6 @@ export enum SmartWeaveTags {
   INTERACT_WRITE = 'Interact-Write',
   WASM_LANG = 'Wasm-Lang',
   WASM_LANG_VERSION = 'Wasm-Lang-Version',
-  WASM_META = 'Wasm-Meta'
+  WASM_META = 'Wasm-Meta',
+  REQUEST_VRF = 'Request-Vrf'
 }

src/core/modules/impl/ArweaveGatewayInteractionsLoader.ts

@@ -71,7 +71,7 @@ export class ArweaveGatewayInteractionsLoader implements InteractionsLoader {
 
   private readonly arweaveWrapper: ArweaveWrapper;
 
-  constructor(private readonly arweave: Arweave) {
+  constructor(protected readonly arweave: Arweave) {
     this.arweaveWrapper = new ArweaveWrapper(arweave);
   }
 

src/core/modules/impl/DefaultStateEvaluator.ts

@@ -15,10 +15,16 @@ import {
   InteractionResult,
   LoggerFactory,
   StateEvaluator,
-  TagsParser
+  TagsParser,
+  VrfData
 } from '@smartweave';
 import Arweave from 'arweave';
 
+import { ProofHoHash } from '@idena/vrf-js';
+import elliptic from 'elliptic';
+
+const EC = new elliptic.ec('secp256k1');
+
 /**
  * This class contains the base functionality of evaluating the contracts state - according
  * to the SmartWeave protocol.
@@ -78,6 +84,12 @@ export abstract class DefaultStateEvaluator implements StateEvaluator {
 
       const interactionTx: GQLNodeInterface = missingInteraction.node;
 
+      if (interactionTx.vrf) {
+        if (!this.verifyVrf(interactionTx.vrf, interactionTx.sortKey, this.arweave)) {
+          throw new Error('Vrf verification failed.');
+        }
+      }
+
       this.logger.debug(
         `[${contractDefinition.txId}][${missingInteraction.node.id}][${missingInteraction.node.block.height}]: ${
           missingInteractions.indexOf(missingInteraction) + 1
@@ -242,6 +254,24 @@ export abstract class DefaultStateEvaluator implements StateEvaluator {
     return evalStateResult;
   }
 
+  private verifyVrf(vrf: VrfData, sortKey: string, arweave: Arweave): boolean {
+    const keys = EC.keyFromPublic(vrf.pubkey, 'hex');
+
+    let hash;
+    try {
+      // ProofHoHash throws its own 'invalid vrf' exception
+      hash = ProofHoHash(
+        keys.getPublic(),
+        arweave.utils.stringToBuffer(sortKey),
+        arweave.utils.b64UrlToBuffer(vrf.proof)
+      );
+    } catch (e: any) {
+      return false;
+    }
+
+    return arweave.utils.bufferTob64Url(hash) == vrf.index;
+  }
+
   private logResult<State>(
     result: InteractionResult<State, unknown>,
     currentTx: GQLNodeInterface,

src/legacy/gqlResult.ts

@@ -51,6 +51,14 @@ export interface GQLNodeInterface {
   confirmationStatus?: string;
   source?: string;
   bundlerTxId?: string;
+  vrf?: VrfData;
+}
+
+export interface VrfData {
+  index: string;
+  proof: string;
+  bigint: string;
+  pubkey: string;
 }
 
 export interface GQLEdgeInterface {

src/legacy/smartweave-global.ts

@@ -1,7 +1,8 @@
 /* eslint-disable */
 import Arweave from 'arweave';
-import { GQLNodeInterface, GQLTagInterface } from './gqlResult';
+import {GQLNodeInterface, GQLTagInterface, VrfData} from './gqlResult';
 import { EvaluationOptions } from '@smartweave/core';
+import {kMaxLength} from "buffer";
 
 /**
  *
@@ -34,6 +35,7 @@ export class SmartWeaveGlobal {
   gasLimit: number;
   transaction: Transaction;
   block: Block;
+  vrf: Vrf;
   arweave: Pick<Arweave, 'ar' | 'wallets' | 'utils' | 'crypto'>;
   contract: {
     id: string;
@@ -102,6 +104,7 @@ export class SmartWeaveGlobal {
         throw new Error('Not implemented - should be set by HandlerApi implementor');
       }
     };
+    this.vrf = new Vrf(this);
 
     this.useGas = this.useGas.bind(this);
   }
@@ -189,3 +192,30 @@ class Block {
     return this.global._activeTx.block.timestamp;
   }
 }
+
+class Vrf {
+  constructor(private readonly global: SmartWeaveGlobal) {}
+
+  get data(): VrfData {
+    return this.global._activeTx.vrf;
+  }
+
+  // returns the original generated random number as a BigInt string;
+  get value(): string {
+    return this.global._activeTx.vrf.bigint;
+  }
+
+  // returns a random value in a range from 1 to maxValue
+  randomInt(maxValue: number): number {
+    if (!Number.isInteger(maxValue)) {
+      throw new Error('Integer max value required for random integer generation');
+    }
+    const result = BigInt(this.global._activeTx.vrf.bigint) % BigInt(maxValue) + BigInt(1);
+
+    if (result > Number.MAX_SAFE_INTEGER || result < Number.MIN_SAFE_INTEGER) {
+      throw new Error('Random int cannot be cast to number');
+    }
+
+    return Number(result);
+  }
+}