In modern web development, particularly for interactive marketing campaigns like lotteries, coupon distribution, or voting systems, securing front-end interfaces is critical. Without proper safeguards, malicious actors can exploit APIs to automate requests, undermining the fairness of the platform. Below are essential security strategies to harden your front-end applications.

1. Secure Password Transmission with SHA-256

When handling user credentials, avoid sending plain-text passwords to the backend. While symmetric encryption (like AES) is reversible if the key is compromised, cryptographic hashing provides a one-way transformation suitable for integrity and security verification.

SHA-256 is recommended for this purpose as it provides high collision resistance. Below is an example of how to hash a password using crypto-js before transmission:

import CryptoJS from 'crypto-js';

const userPassword = "UserSecurePassword123";
// Hash the password with SHA-256
const hashedCredential = CryptoJS.SHA256(userPassword).toString();

console.log("Transmission-ready hash:", hashedCredential);

2. Restricting Web Crawlers

To prevent search engines or automated scrapers from indexing unauthorized pages or sensitive API endpoints, utilize a robots.txt file. If you are using a build tool like Webpack, ensure the file is correctly deployed to your root directory:

// vue.config.js snippet
const path = require('path');
const CopyWebpackPlugin = require('copy-webpack-plugin');

module.exports = {
 configureWebpack: {
   plugins: [
     new CopyWebpackPlugin([{
       from: path.resolve(__dirname, './public/robots.txt'),
       to: './'
     }])
   ]
 }
};

3. Inhibiting Debugging and Client-Side Manipulation

While client-side code cannot be fully hidden, you can implement friction to deter casual attackers from inspecting your logic or intercepting network rqeuests.

Blocking Developer Tools: You can monitor for keyboard shortcuts and events typically used to access browser debugging features. When detected, you can programmatically close the tab or redirect the user.

// Security deterrent script
document.addEventListener('keydown', (e) => {
   // Detect F12, Ctrl+Shift+I, or Ctrl+S
   if (e.key === 'F12' || (e.ctrlKey && e.shiftKey && e.key === 'I') || (e.ctrlKey && e.key === 's')) {
       e.preventDefault();
       window.location.href = 'about:blank';
   }
});

// Disable right-click context menu
document.oncontextmenu = (e) => {
   e.preventDefault();
   return false;
};

// Detect console usage via window resize (often triggered by DevTools opening)
const baseWidth = window.innerWidth;
const baseHeight = window.innerHeight;
window.addEventListener('resize', () => {
   if (window.innerWidth !== baseWidth || window.innerHeight !== baseHeight) {
       window.location.href = 'about:blank';
   }
});

Note: These client-side measures provide a layer of obfuscation but should never replace robust server-side authentication, rate limiting, and input validation. Always assume the client environment is untrusted.