Added 'altcha' captcha system for account and channel creation.

src/utils/altchaUtils.js

@@ -0,0 +1,61 @@
+/*Canopy - The next generation of stoner streaming software
+Copyright (C) 2024  Rainbownapkin and the TTN Community
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.*/
+
+//Config
+const config = require('../../config.json');
+
+//NPM imports
+const { createChallenge, verifySolution } = require('altcha-lib');
+
+//Create empty array to hold cache of spent payloades to protect against replay attacks
+const spent = [];
+//Captcha lifetime in minutes
+const lifetime = 2;
+
+module.exports.genCaptcha = async function(){
+    //Set altcha expiration date
+    const expiration = new Date();
+
+    //Add four minutes
+    expiration.setMinutes(expiration.getMinutes() + lifetime);
+
+    //Generate Altcha Challenge
+    return await createChallenge({
+        hmacKey: config.altchaSecret,
+        maxNumber: 200000,
+        expires: expiration
+    });
+}
+
+module.exports.verify = async function(payload){
+    //If we already checked this payload
+    if(spent.indexOf(payload) != -1){
+        //Fuck off and die
+        return false;
+    }
+
+    //Get length before pushing payload to get index of next item
+    const payloadIndex = spent.length;
+
+    //Add payload to cache of spent payloades
+    spent.push(payload);
+
+    //Set timeout to splice out the used payload after its expired so we're not filling RAM with expired payloads that aren't going to resolve true anyways
+    setTimeout(() => {spent.splice(payloadIndex,1);}, lifetime * 60 * 1000);
+
+    //Return verification results
+    return await verifySolution(payload, config.altchaSecret);
+}