Once, I wrote about hash function that I improved. Though, that was C#. In this post I will show you how to get hash code with Java Script. (previous post)

function getStableHash(input,hashLength)
{
	/* Copyright (C) 2012 Artem Los,
	 * All rights reserved.
	 *
	 * code based on:
	 * http://blog.clizware.net/news/631
	 *
	 * originaly from: http://stackoverflow.com/questions/548158/fixed-length-numeric-hash-code-from-variable-length-string-in-c-sharp
	 */	

	 var _length = Math.pow(10,hashLength); //result in 10 numbers, if hashLength is 10
	 var hash = 0;

	 for (var j = 0; j < input.length; j++)
	 {
		 hash += input.charCodeAt(j);
		 hash += (hash << 10);
		 hash ^= (hash >> 6);
	 }

	 hash += (hash << 3);
	 hash ^= (hash >> 11);
	 hash += (hash << 15);

	 var result = ((hash % _length) + _length) % _length;//hash.mod(_length)

	 var check = parseInt(_length / result);
	 if (check > 1)
	 {
		 result *= check;
	 }

	 return result;
}

In order to calculate a hash value, you need to define two main variables. First of all, the string to calculate hash from (input), and eventually, the length of the result (hashLength). It is recommended that you set the hashLength to 8 or in some cases 10.

Please take a look at this code in work http://editor.clizware.net/?id=9

Another good method to encrypt ASCII based text. To view this example in work, http://editor.clizware.net/?id=7 (remember to press compile)

//Copyright (C) 2012 Artem Los, All rights reserved

function mod_c(text,key,enc_dec)
{
	//only for 128 ascii values
	if (key == "")
	{
		return "Error: no key given";
	}
	if (enc_dec === true)
	{
		var result = "";

		for (var i=0; i < text.length; i++)
		{
			result += String.fromCharCode( (text.charCodeAt(i) + key.charCodeAt(i % key.length)).mod(128)    );
		}
		return result;
	}
	else if(enc_dec === false)
	{
		var result = "";

		for (var i=0; i < text.length; i++)
		{
			result += String.fromCharCode( (text.charCodeAt(i) - key.charCodeAt(i % key.length)).mod(128)  );
		}
		return result;
	}
	else
	{
		return "Error: enc_dec is not given";
	}
}

Number.prototype.mod = function(n) {
return ((this%n)+n)%n;
}

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>