Webhook Setup

import json
from flask import request
from Crypto.PublicKey import RSA
from Crypto.Signature import pkcs1_15
from Crypto.Hash import SHA256
import base64
import binascii

# Place your public key according to the environment
public_key_b64 = "YOUR_PUBLIC_KEY"

def callback_notice():
    # Step 1: Extract the raw body and signature header
    param = request.get_data(as_text=True)
    signature_hex = request.headers.get('signature')

    # Step 2: Verify RSA-SHA256 signature (hex-encoded)
    verified = sha256_rsa_verify(param, signature_hex, public_key_b64)
    print(f"verified:{verified}")

    return json.dumps({"callbackStatus": "SUCCESS" if verified else "FAIL"})

def sha256_rsa_verify(data: str, signature_hex: str, public_key_b64: str) -> bool:
    try:
        # Decode the Base64 public key and import it
        pub_key_bytes = base64.b64decode(public_key_b64)
        public_key = RSA.import_key(pub_key_bytes)

        # Hash the message
        h = SHA256.new(data.encode("utf-8"))

        # Decode the hex signature to bytes
        sig_bytes = binascii.unhexlify(signature_hex)

        # Verify
        pkcs1_15.new(public_key).verify(h, sig_bytes)
        return True
    except (ValueError, TypeError):
        return False

const crypto = require('crypto');

// Place your public key according to the environment
// The key should be in PEM format or you can derive it from the Base64 string
const publicKeyBase64 = "YOUR_PUBLIC_KEY";

async function callbackNotice(req, param) {
    // Step 1: Extract the signature header
    const signatureHex = req.headers['signature'];

    // Step 2: Verify the RSA-SHA256 signature (hex-encoded)
    const verified = await verifyRSASHA256(param, signatureHex, publicKeyBase64);
    console.log(`verified: ${verified}`);

    return JSON.stringify({
        callbackStatus: verified ? "SUCCESS" : "FAIL"
    });
}

async function verifyRSASHA256(data, signatureHex, publicKeyBase64) {
    try {
        // Convert Base64 public key to PEM format
        const pem = `-----BEGIN PUBLIC KEY-----\n${publicKeyBase64}\n-----END PUBLIC KEY-----`;

        // Convert hex signature to Buffer
        const signatureBuffer = Buffer.from(signatureHex, 'hex');

        // Create verifier
        const verify = crypto.createVerify('RSA-SHA256');
        verify.update(data, 'utf8');

        return verify.verify(pem, signatureBuffer);
    } catch (err) {
        console.error('Verification error:', err);
        return false;
    }
}