cybersource-rest-client/src/utilities/flex/TokenVerification.js

Node.js SDK for the CyberSource REST API

'use strict';

const crypto = require('crypto');
const jwkToPem = require('jwk-to-pem');

/**
 * This function has all the merchentConfig properties getters and setters methods
 * 
 * @param  result 
 */
function TokenVerification() {

}

function isPemFormattedString(input) {
  	return typeof input === 'string' && /^-----BEGIN PUBLIC KEY-----[\S\s]*-----END PUBLIC KEY-----/.test(input);
  }
   
  function isBase64String(input) {
  	return typeof input === 'string' && /^[a-zA-Z0-9+/=]*$/g.test(input);
  }
   
  function base64toPem(base64) {
  	const urlDecoded = base64.replace(/-/g, '+').replace(/_/g, '/');
   
  	return [
  		'-----BEGIN PUBLIC KEY-----',
  		...urlDecoded.match(/.{1,64}/g),
  		'-----END PUBLIC KEY-----',
  	].join('\n');
  }

TokenVerification.prototype.verifyToken = function verifyToken(publicKey, token) {
    if (typeof token !== 'object' || !token) throw new Error('Invalid token object');
	if (!Object.prototype.hasOwnProperty.call(token, 'signature')) throw new Error('token.signature is missing');
	if (!Object.prototype.hasOwnProperty.call(token, 'signedFields')) throw new Error('token.signedFields is missing');
 
	let pem;
	if (typeof publicKey === 'object') pem = jwkToPem(publicKey);
	else if (isPemFormattedString(publicKey)) pem = publicKey;
	else if (isBase64String(publicKey)) pem = base64toPem(publicKey);
	else {
		throw new Error('Invalid publicKey parameter');
	}
 
	const dataToVerify = token.signedFields.split(',').map(field => token[field]).join(',');
	return crypto.createVerify('RSA-SHA512').update(dataToVerify).verify(pem, token.signature, 'base64');
};

module.exports = TokenVerification;