generate hash+timestamp string & validate hash+timestamp string from userland

hash-timestamp.js

/**
 * generate hash+timestamp string
 * validate hash+timestamp string from userland
 */
const crypto = require('crypto');

const SECRET = ' ';

function _generateHash(isoDateString) {
    return crypto
        .createHmac('sha256', SECRET)
        .update(isoDateString)
        .digest('base64');
}

function _validateSignature(hash, isoDateString) {
    const hashFromInput = _generateHash(isoDateString);

    return hashFromInput === hash;
}

function generateHashTimestampString() {
    const isoDateString = new Date().toISOString();
    const hash = _generateHash(isoDateString);

    return `${hash} ${isoDateString}`;
}

function validateHashTimestampString(hashTimestampString) {
    const [hash, isoDateString] = hashTimestampString.split(' ');

    return _validateSignature(hash, isoDateString);
}

// const hashTimestampString = generateHashTimestampString();
// const isValid = validateHashTimestampString(hashTimestampString);

// example usage
const isValid = validateHashTimestampString('hmnm5OHx3tTcBaZPnse2mShNJSqOCxoUIr1RBZlGPMY= 2017-10-26T15:43:25.798Z');

if (!isValid) {
    throw new Error('Hash mismatch.');
}