EDIT: Please check out the updated version of this article.

When encrypting a website, we need to understand the way a browser interprets our input, i.e. html/javascript. In this case, we can produce code that is only readable by a browser.

There are several ways to encrypt a page, the main idea behind all methods is it to convert a human-readable code to ONLY computer-readable one.

• By HTML only
• By JavaScript
  • Using hexadecimal values
  • Using “escape/unescape”
  • Using an advanced algarithm

By HTML Only
In HTML, all letters(chars) can be written in a ASCII form, i.e., if we have a small “a” that is to be converted, we simply look up its ASCII value and write it instead of the actual char: a, and so on.To sum up, the prefix is “&#”, then the ASCII code, and lastly a semicolon, “;”.

function encToASCII(_text)
{
	var _newText="";

	for(var i=0; i < _text.length;i++)
	{
		_newText += "&#" + _text.charCodeAt(i) + ";";
	}

	return _newText;
}

By JavaScript
JavaScript website encryption can be divided into several parts. One way is by using the hexadecimal value of a char, and write it instead of the actual char. We have to use JavaScript to perform this action, as it is shown below:

function encToHex(_text)
{
	var _newText="";
	for (var i=0; i < _text.length; i++)
	{
		_newText += "%" + decimalToHex(_text.charCodeAt(i));
	}
	return _newText;
}
function decimalToHex(_num)
{
	return _num.toString(16);
}

This method will only encrypt the given text, though, but, the user has to be able to see the encrypted text as a result (the browser won’t understand this code unless we have a function that will interpret it). This method is based on JavaScript, and we therefore need to use JavaScript to decrypt. Let us say that we encrypt “Hello World!”, which results “%48%65%6c%6c%6f%20%57%6f%72%6c%64%21”. As you might see, the prefix is “%”, and then the hexadecimal number. If the result above is our webpage, the source of that webpage should look similar to the example below:

<script type="text/javascript">
document.write(unescape("%48%65%6c%6c%6f%20%57%6f%72%6c%64%21"));
</script>

There is also, as you might see, an opportunity to use functions escape and unescape as they are. Their actual usage is to encode/decode the url, i.e., replacing spaces, “special chars.” to url friendly one. All letters and numbers will stay the same, they will not be changed.

document.write(escape("Hello World!"));

The result you will get is Hello%20World%21. It replaces spaces with %20, and “!” with %21. Both of them are special characters(chars).

Unescape function will decode to a normal string.

document.write(unescape("Hello%20World%21"));

function en_doc(t,k)
{
	var a;
	var b;
	var r=new Array();
	for (var i=0; i<t.length ;i++)
	{
		a=t.charCodeAt(i);
		b=k.charAt(i%k.length);
		a^=b;
		r[i]=String.fromCharCode(a);
	}
	return r.join("");
}

The code shown above is my own advanced algorithm. First, we declare “a”, which is a char at certain place in string t; and b, which is a digit at certain place in k. The text to encrypt is placed in t (all chars), and the key to encrypt with is placed in k (only digits). The variable r is an array of the result/output.

First of all, we assign a to the char code at i. The variable b is then assigned to the char at i mod the length of key.

<script src="https://dev.clizware.net/lib/scrypto1.js"></script>

<script src="https://clizware.webs.com/lib/scrypto1.js"></script>

In this post I will go through a simple encryption method I’ve done few years ago. It is actually so simple, but I’ve heard that some currently-used encryption algorithms are based on this principle.

Here is the code: (function “ec_t” – encryption method; function “dc_t” – decryption method)

/*
 * Sample encryption and
 * decryption by Artem Los
 * 
 */ 

  //Encrypt
    function ec_t(t, key) {
        var c = "";
        var d = "";
        var _key2 = StringToAsc(key);
        var e = genKey(_key2 , t.length);
        var _keyA =  new String (key.length);

        for (i = 0; i < t.length; i++) {

            var _def_t = eval(t.charCodeAt(i));
            var _def_e = eval(e.charAt(i));
            var _def_a = eval(_keyA.charAt(0));

            c = _def_e + _def_t +_def_a;
            d += String.fromCharCode (c);

        }
        return d;
    }

    function genKey(key, l) {
        var _vectorA = key;
        while (_vectorA.length < l) {
            _vectorA += _vectorA;
        }
        return _vectorA;
    }
    function StringToAsc(text) {
        var _vectorA = "";

        for (i = 0; i < text.length; i++) {
            _vectorA +=  text.charCodeAt(i);
        }
        return _vectorA;
    }

    //Decrypt
    function dc_t(t, key) {
        var c = "";
        var d = "";
        var _key2 = StringToAsc(key);
        var _keyA = new String(key.length);
        var e = genKey(_key2, t.length);

        for (i = 0; i < t.length; i++) {

            c = t.charCodeAt(i) - e.charAt(i) - _keyA.charAt (0);
            d +=  String.fromCharCode (c);
        }
        return d;

    }

    function do_e() {

        var _vecB = unescape (  in01.value);
        var _passA = pass.value;

        if (_passA != "") {
            if (ra01.checked == true) {
                var _vecC = ec_t(_vecB, _passA );
                in02.value = escape ( _vecC);
            }

            else {
                    var _vecC = dc_t(_vecB , _passA);
                    in02.value = _vecC;
            }
        }
    }

If you want to view this code in-work, enter the link below:
Encrypter

Why and how did it work?
The code above works on a simple principle, I discovered it without looking at internet, though! 😛

Say we have a table where all letters have an id, i.e., a number. The table looks as follows: A-1, B-2, C-3 …
First of all, we need to define our message, say we have “BAC” corresponding to “213”.
Then we need a key, say “CBA” – “321”. (it is in the same format as the message).

The result is therefore 435 or DCE. When we decrypt we have to do the same but backwards, using the key, i.e., instead of addition use subtraction.

This is done with function “ec_t” and “dc_t”.
If the message is longer than the key, then we need to duplicate the key so it matches the message length. All that is done in function “getKey”.

It is better that you use function “do_e” instead of “ec_t”, because then all letters will go through a escape function, which means that the text will be more copy-friendly, i.e., easier to copy without missing some letters which can affect the result.

Good luck!