Bird - Webhook signature verification nodeJS

import crypto from "crypto";

class SignedRequest {
  constructor(requestSignature, requestTimestamp, requestBody, requestUrl) {
    this._requestSignature = requestSignature;
    this._requestTimestamp = requestTimestamp.toString();
    this._requestBody = requestBody;
    this._requestUrl = requestUrl;
  }

  verify(signingKey) {
    const payload = this._buildPayload();
    const expectedSignature = Buffer.from(this._requestSignature, "base64");
    const calculatedSignature = crypto
      .createHmac("sha256", Buffer.from(signingKey, "latin1"))
      .update(Buffer.from(payload, "latin1"))
      .digest();
    return expectedSignature.equals(calculatedSignature);
  }

  _buildPayload() {
    const checksumBody = crypto
      .createHash("sha256")
      .update(Buffer.from(this._requestBody, "latin1"))
      .digest();
    const strChecksumBody = checksumBody.toString("latin1");
    const parts = [this._requestTimestamp, this._requestUrl, strChecksumBody];
    return parts.join("\n");
  }
}

const sig = "lrv/39nhNz0qRfvAc/2cP8tqPpW1ZoRg8yqvM2WFDiA=";
const timestamp = "1719823259";
const body = {
  service: "channels",
  event: "whatsapp.outbound",
  payload: {
    id: "351fe763-99eb-4cc3-bd4c-1ce661fdc075",
    channelId: "aeb8f6af-d330-467b-9778-835144431687",
    sender: {
      connector: {
        id: "216852e9-5eaa-4c8c-b33c-572210004b9f",
        identifierValue: "104587572718860",
      },
    },
    receiver: {
      contacts: [
        {
          id: "bfda0e99-9454-47d7-afc3-447e15642bf3",
          identifierKey: "phonenumber",
          identifierValue: "+33757909733",
          annotations: { name: "Quentin Hausser" },
          countryCode: "FR",
        },
      ],
    },
    reference: "",
    status: "accepted",
    reason: "",
    lastStatusAt: "2024-07-01T08:40:58.363Z",
    createdAt: "2024-07-01T08:40:58.363Z",
    updatedAt: "2024-07-01T08:40:58.363Z",
  },
};

const url = "https://webhook.site/bb7e434b-2aeb-463c-82f5-6b05af10461e";
const test = new SignedRequest(sig, timestamp, JSON.stringify(body), url);
console.log(test.verify("thisiscryptos"));