Javascript token generation

xor_encryption.js

function getRandomInt(min, max) {
    min = Math.ceil(min);
    max = Math.floor(max);
    return Math.floor(Math.random() * (max - min + 1)) + min;
}

function encrypt(plaintext, key) {
    let cyphertext = [];
    // Convert to hex to properly handle UTF8
    plaintext = Array.from(plaintext).map(function (c) {
        if (c.charCodeAt(0) < 128) return c.charCodeAt(0).toString(16).padStart(2, '0');
        else return encodeURIComponent(c).replace(/\%/g, '').toLowerCase();
    }).join('');
    // Convert each hex to decimal
    plaintext = plaintext.match(/.{1,2}/g).map(x => parseInt(x, 16));
    // Perform xor operation
    for (let i = 0; i < plaintext.length; i++) {
        cyphertext.push(plaintext[i] ^ key.charCodeAt(Math.floor(i % key.length)));
    }
    // Convert to hex
    cyphertext = cyphertext.map(function (x) {
        return x.toString(16).padStart(2, '0');
    });
    return cyphertext.join('');
}

// Super simple XOR decrypt function
function decrypt(cyphertext, key) {
    try {
        cyphertext = cyphertext.match(/.{1,2}/g).map(x => parseInt(x, 16));
        let plaintext = [];
        for (let i = 0; i < cyphertext.length; i++) {
            plaintext.push((cyphertext[i] ^ key.charCodeAt(Math.floor(i % key.length))).toString(16).padStart(2, '0'));
        }
        return decodeURIComponent('%' + plaintext.join('').match(/.{1,2}/g).join('%'));
    } catch (e) {
        return false;
    }
}

function generateRandomToken(passphrase, min, max, debug){
	var randomVal = ''+getRandomInt(min, max);
	var token = encrypt(passphrase.toUpperCase(), ('' + getRandomInt(min, max)).toUpperCase());
	if(debug)
        	console.log("Token generated: " + token.toUpperCase() + "\nPassphrase: " + passphrase.toUpperCase() + "\nKey: " + randomVal);
	return token;
}

function findKey(token, passphrase, min, max, debug) {
    var key = -1;
    for (i = min; i <= max; i++) {
        var test = decrypt(token, '' + i);
	if(debug)
        	console.log("Token: " + token.toUpperCase() + "\tKey: " + i + "\tDecrypted: " + test.toUpperCase());
        if (test.toUpperCase() === passphrase.toUpperCase()) {
            key = i;
        }
    }
    if (key >= 0) {
        console.log("FOUND!\nToken: " + token.toUpperCase() + "\nPassphrase: " + passphrase.toUpperCase() + "\nKey: " + key);
    }
    return key;
}
var min = 1;
var max = 200;
var passphrase = "sl_code!9"
var passkey = generateRandomToken(passphrase, min, max, false)
var found_key = findKey(passkey, passphrase, min, max, false)
jQuery("#random_token_voucher").text(('' + passkey).toUpperCase())