@bsv/sdk/src/auth/utils/verifyNonce.ts

BSV Blockchain Software Development Kit

import * as Utils from '../../primitives/utils.js'
import { WalletInterface, WalletCounterparty, Base64String, OriginatorDomainNameStringUnder250Bytes } from '../../wallet/Wallet.interfaces.js'

/**
 * Verifies a nonce derived from a wallet
 * @param nonce - A nonce to verify as a base64 string.
 * @param wallet
 * @param counterparty - The counterparty to the nonce creation. Defaults to 'self'.
 * @returns The status of the validation
 */
export async function verifyNonce(
  nonce: Base64String,
  wallet: WalletInterface,
  counterparty: WalletCounterparty = 'self',
  originator?: OriginatorDomainNameStringUnder250Bytes
): Promise<boolean> {
  // Convert nonce from base64 string to Uint8Array
  const buffer = Utils.toArray(nonce, 'base64')

  // Split the nonce buffer
  const data = buffer.slice(0, 16)
  const hmac = buffer.slice(16)

  // Calculate the HMAC
  const { valid } = await wallet.verifyHmac({
    data,
    hmac,
    protocolID: [2, 'server hmac'],
    keyID: Utils.toUTF8(data),
    counterparty
  }, originator)

  return valid
}