Add support for evmnet

lib/beacon-verification.ts

@@ -1,5 +1,8 @@
 import { bls12_381 as bls } from '@noble/curves/bls12-381'
+import { bn254 } from '@kevincharm/noble-bn254-drand'
+import type { CHash } from '@noble/curves/abstract/utils'
 import { sha256 } from '@noble/hashes/sha256'
+import { keccak_256 } from '@noble/hashes/sha3'
 import { ensureBytes } from '@noble/curves/abstract/utils'
 import {Buffer} from 'buffer'
 import {
@@ -11,7 +14,8 @@ import {
  G2UnchainedBeacon,
  isG1G2SwappedBeacon,
  G1UnchainedBeacon,
- isG1Rfc9380
+ isG1Rfc9380,
+ isBn254OnG1
 } from './index'
 
 type PointG1 = typeof bls.G1.ProjectivePoint.ZERO
@@ -46,6 +50,12 @@ async function verifyBeacon(chainInfo: ChainInfo, beacon: RandomnessBeacon, expe
  return verifySigOnG1(beacon.signature, await unchainedBeaconMessage(beacon), publicKey, 'BLS_SIG_BLS12381G1_XMD:SHA-256_SSWU_RO_NUL_')
  }
 
+ if (isBn254OnG1(beacon, chainInfo)) {
+ return bn254.verifyShortSignature(beacon.signature, await unchainedBeaconMessage(beacon, keccak_256), publicKey, {
+ DST: 'BLS_SIG_BN254G1_XMD:KECCAK-256_SVDW_RO_NUL_'
+ })
+ }
+
  console.error(`Beacon type ${chainInfo.schemeID} was not supported or the beacon was not of the purported type`)
  return false
 
@@ -93,8 +103,8 @@ async function chainedBeaconMessage(beacon: G2ChainedBeacon): Promise<Uint8Array
  return sha256(message)
 }
 
-async function unchainedBeaconMessage(beacon: G2UnchainedBeacon | G1UnchainedBeacon): Promise<Uint8Array> {
- return sha256(roundBuffer(beacon.round))
+async function unchainedBeaconMessage(beacon: G2UnchainedBeacon | G1UnchainedBeacon, hashFn: CHash = sha256): Promise<Uint8Array> {
+ return hashFn(roundBuffer(beacon.round))
 }
 
 function signatureBuffer(sig: string) {

lib/index.ts

@@ -144,7 +144,7 @@ export type ChainInfo = {
 }
 
 // currently drand supports chained and unchained randomness - read more here: https://drand.love/docs/cryptography/#randomness
-export type RandomnessBeacon = G2ChainedBeacon | G2UnchainedBeacon | G1UnchainedBeacon | G1RFC9380Beacon
+export type RandomnessBeacon = G2ChainedBeacon | G2UnchainedBeacon | G1UnchainedBeacon | G1RFC9380Beacon | Bn254OnG1Beacon
 
 export type G2ChainedBeacon = {
  round: number
@@ -177,6 +177,14 @@ export type G1RFC9380Beacon = {
  _phantomg19380?: never
 }
 
+export type Bn254OnG1Beacon = {
+ round: number
+ randomness: string
+ signature: string
+ // this distinguishes it from the other unchained beacons so the type guard works correctly
+ _phantombn254ong1?: never
+}
+
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 export function isChainedBeacon(value: any, info: ChainInfo): value is G2ChainedBeacon {
  return info.schemeID === 'pedersen-bls-chained' &&
@@ -214,6 +222,15 @@ export function isG1Rfc9380(value: any, info: ChainInfo): value is G1RFC9380Beac
  value.round > 0
 }
 
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export function isBn254OnG1(value: any, info: ChainInfo): value is Bn254OnG1Beacon {
+ return info.schemeID === 'bls-bn254-unchained-on-g1' &&
+ !!value.randomness &&
+ !!value.signature &&
+ value.previous_signature === undefined &&
+ value.round > 0
+}
+
 // exports some default implementations of the above interfaces and other utility functions that could be used with them
 export {
  HttpChain,

package.json

@@ -31,7 +31,8 @@
  },
  "dependencies": {
  "@babel/traverse": "^7.23.2",
- "@noble/curves": "^1.4.0",
+ "@kevincharm/noble-bn254-drand": "^0.0.1",
+ "@noble/curves": "^1.6.0",
  "buffer": "^6.0.3"
  },
  "repository": {

test/beacon-verification.test.ts

@@ -207,4 +207,29 @@ describe('verifyBeacon', () => {
  await expect(verifyBeacon(chainInfo, validBeacon, 2)).resolves.toEqual(false)
  })
  })
+
+ describe('signatures on BN254 G1', () => {
+ // TODO: Replace data with evmnet when it's live
+ const validBeacon = {
+ round: 10,
+ signature:
+ '0fd919ec1490bf01935f348837bd20f49f539c5adfd60ce29648fe16f8dbed8803bf3e8fb4c3cbce5dcb642333d81260a811cc432b2f7a687b9b7c2305ad01ee',
+ randomness: 'a62a0e81920b40fb361f9106efb34199af1fbdb0c53db51f7acbad73e0d9d0bf',
+ }
+
+ const chainInfo = {
+ public_key:
+ '14018a8127d0cd185f0d0cd168bec330c584581d46f77f41e8ee33ad600588e104961f20efbcec8ce5e176aa182bf141f7059cfb467e3b508bc6f36f227d5cf31c7baa2a010677e813ffca24b4ff5faf3348b2750201c85b126a480118b149f514d3e7aba46a99f40aac6507a2c6d6f3c7a6b38038786831e3e6b5b0adf5894b',
+ period: 3,
+ genesis_time: 1726958055,
+ hash: 'f50064cd5f71a2e2de647940ac7fa2fd9f6128129ada163e971625ec9f082db2',
+ groupHash: '3a7cd8aa1864ff0cf8837e1bf77dad871aaaa8f046041ccecce74ab4e029f30c',
+ schemeID: 'bls-bn254-unchained-on-g1',
+ metadata: { beaconID: 'default' },
+ }
+
+ it('should verify a valid signature', async () => {
+ await expect(verifyBeacon(chainInfo, validBeacon, validBeacon.round)).resolves.toEqual(true)
+ })
+ })
 })