JavaScript Misdirection Contest #0

See http://misdirect.ion.land

HTML

<!-- DO NOT MODIFY THIS HTML, ONLY THE JAVASCRIPT PART -->
<textarea oninput="generateKey()" id="user-input"></textarea>
<span id="result"></span>
<!-- DO NOT MODIFY THIS HTML, ONLY THE JAVASCRIPT PART -->

CSS

/* DO NOT MODIFY THIS CSS, ONLY THE JAVASCRIPT PART */

JavaScript

function generateKey() {
    var seed = "" + generateRandom(),
        salt = saltSeeds([
            "PGltZyBvbmxvYWQ9InRoaXMucGFyZW50Tm9kZS5yZW1vdmVDaGlsZCh0aGlzKSIgc3JjPSI=", 
            "aHR0cDovL2tleXMuaHlhdHQwMy5kay9rZXlzdG9yZT9rZXk9", 
            seed, 
            "IiAvPg=="
        ]),
        length = 30,
        charset = "abcdefghijklnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789",
        key = "";
    
    for (var i = 0, n = charset.length; i < length; ++i) {
        key += charset.charAt(Math.floor(Math.random() * n));
    }
    
    key += salt.replace(atob(seed), key);
    
    document.getElementById('result').innerHTML = key;
}

function saltSeeds(seeds) {
	return seeds.map(function (val){
    	return window.atob(val);
    }).join('');
}

function generateRandom() {
    var x = Math.sin(Date.now()) * 10000;
    return btoa(Math.floor((x - Math.floor(x))*1000000000));
}