Signature Verification

Every webhook request includes a signature header that you should verify to ensure the request is genuinely from Ikawaari.

How It Works

Each webhook endpoint has a unique signing secret (starts with whsec_). Ikawaari uses this secret to generate an HMAC-SHA256 signature included in the Ikawaari-Signature header.

Verification Steps

1. Extract the signature

Ikawaari-Signature: t=1708300800,v1=5257a869e7ecebeda32affa62cdca3fa51cad7e77a0e56ff536d0ce8e108d8bd

2. Prepare the signed payload

{timestamp}.{raw_body}

3. Compute the expected signature

Node.js

const crypto = require('crypto');

function verifyWebhookSignature(payload, header, secret) {
  const [tPart, vPart] = header.split(',');
  const timestamp = tPart.split('=')[1];
  const signature = vPart.split('=')[1];

  const signedPayload = `${timestamp}.${payload}`;
  const expected = crypto
    .createHmac('sha256', secret)
    .update(signedPayload)
    .digest('hex');

  // Timing-safe comparison
  return crypto.timingSafeEqual(
    Buffer.from(signature),
    Buffer.from(expected)
  );
}

Python

import hmac
import hashlib

def verify_webhook_signature(payload: str, header: str, secret: str) -> bool:
    parts = dict(p.split("=", 1) for p in header.split(","))
    timestamp = parts["t"]
    signature = parts["v1"]

    signed_payload = f"{timestamp}.{payload}"
    expected = hmac.new(
        secret.encode(), signed_payload.encode(), hashlib.sha256
    ).hexdigest()

    return hmac.compare_digest(signature, expected)

4. Reject stale events

Check that the timestamp is within 5 minutes of the current time to prevent replay attacks.

attention

Always verify webhook signatures in production. Never trust webhook payloads without verification.