Validate signatures

import crypto from 'node:crypto';

function isFromKira(rawBody, headerValue, secret) {
  const expected = crypto
    .createHmac('sha256', secret)
    .update(rawBody)
    .digest('hex');

  const a = Buffer.from(expected, 'utf8');
  const b = Buffer.from(headerValue ?? '', 'utf8');

  return a.length === b.length && crypto.timingSafeEqual(a, b);
}

import hashlib
import hmac

def is_from_kira(raw_body: bytes, header_value: str, secret: str) -> bool:
    expected = hmac.new(
        secret.encode(), raw_body, hashlib.sha256
    ).hexdigest()
    return hmac.compare_digest(expected, header_value or "")