Encryption / decryption controls

/************************************************************************************************************
                   Encryption/decryption script written by Mark Wilton-Jones - 2002
*************************************************************************************************************

Please see http://www.howtocreate.co.uk/jslibs/ for details and a demo of this script
Please see http://www.howtocreate.co.uk/jslibs/termsOfUse.html for terms of use
_________________________________________________________________________

This script can encrypt or decrypt text using a user-defined password (best kept to 8 characters max).

To use:
_________________________________________________________________________

Inbetween the <head> tags, put:

	<script src="PATH TO SCRIPT/comphash.js" type="text/javascript" language="javascript1.2"></script>

To invoke this script, use:

	For encryption:
		var myOutput = completeHash('TEXT TO ENCRYPT','password')

	For decryption:
		var myOutput = unHash('ENCRYPTED TEXT','password')

*******************************************************************************************************
                               And here's the actual code
******************************************************************************************************/

function completeEscape(oString) {
	var strArray = new Array(), fromChar = new Array();
	for( var x = 0; x < oString.length; x++ ) { strArray[x] = oString.charAt( x ); }
	//lower case
	fromChar['a'] = '61'; fromChar['b'] = '62'; fromChar['c'] = '63'; fromChar['d'] = '64'; fromChar['e'] = '65';
	fromChar['f'] = '66'; fromChar['g'] = '67'; fromChar['h'] = '68'; fromChar['i'] = '69'; fromChar['j'] = '6A';
	fromChar['k'] = '6B'; fromChar['l'] = '6C'; fromChar['m'] = '6D'; fromChar['n'] = '6E'; fromChar['o'] = '6F';
	fromChar['p'] = '70'; fromChar['q'] = '71'; fromChar['r'] = '72'; fromChar['s'] = '73'; fromChar['t'] = '74';
	fromChar['u'] = '75'; fromChar['v'] = '76'; fromChar['w'] = '77'; fromChar['x'] = '78'; fromChar['y'] = '79';
	fromChar['z'] = '7A';
	//upper case
	fromChar['A'] = '41'; fromChar['B'] = '42'; fromChar['C'] = '43'; fromChar['D'] = '44'; fromChar['E'] = '45';
	fromChar['F'] = '46'; fromChar['G'] = '47'; fromChar['H'] = '48'; fromChar['I'] = '49'; fromChar['J'] = '4A';
	fromChar['K'] = '4B'; fromChar['L'] = '4C'; fromChar['M'] = '4D'; fromChar['N'] = '4E'; fromChar['O'] = '4F';
	fromChar['P'] = '50'; fromChar['Q'] = '51'; fromChar['R'] = '52'; fromChar['S'] = '53'; fromChar['T'] = '54';
	fromChar['U'] = '55'; fromChar['V'] = '56'; fromChar['W'] = '57'; fromChar['X'] = '58'; fromChar['Y'] = '59';
	fromChar['Z'] = '5A';
	//numbers
	fromChar['0'] = '30'; fromChar['1'] = '31'; fromChar['2'] = '32'; fromChar['3'] = '33'; fromChar['4'] = '34';
	fromChar['5'] = '35'; fromChar['6'] = '36'; fromChar['7'] = '37'; fromChar['8'] = '38'; fromChar['9'] = '39';
	//misc
	fromChar['*'] = '2A'; fromChar['/'] = '2F'; fromChar['_'] = '5F'; fromChar['+'] = '2B'; fromChar['-'] = '2D';
	fromChar['@'] = '40'; fromChar['.'] = '2E';

	for( var x = 0; x < strArray.length; x++ ) {
		strArray[x] = ( strArray[x] == escape( strArray[x] ) ) ? ( fromChar[strArray[x]] ) : escape( strArray[x] ).replace( /%/, '' ); }
	return strArray.join( '' );
}

function completeHash(oString,oKey) {
	if( oKey.length < 5 ) { window.alert( 'The key must be at least 5 characters long' ); return oString; }
	var oKeyNum = new Array(), oOutStr = '', oOp = new Array('+=','/=','-=','*= 0.01 *');
	for( var x = 0; x < oKey.length; x++ ) { oKeyNum[x] = parseInt( '0x' + completeEscape( oKey.charAt( x ) ) ); }
	for( var x = 0, y = ''; x < oString.length; x += Math.round( oKey.length / 2 ), y = 'O.O' ) {
		var theNum = parseInt( '0x' + completeEscape( oString.substr( x, Math.round( oKey.length / 2 ) ) ) );
		if( isNaN( theNum ) ) { window.alert( 'Encrypton failed.\nYour browser treated a character as a member of the extended\ncharacter set instead of a member of the standard Ascii\ncharacter set.\nI recommend using Netscape 4 if you want to encrypt this\ntext as it does not suffer from that problem.' ); return oString; }
		for( var z = 0; z < oKey.length; z++ ) { eval( 'theNum ' + oOp[z % 4] + ' ' + oKeyNum[z] + ';' ); }
		oOutStr += y + theNum; }
	return oOutStr;
}

function unHash(oString,oKey) {
	if( oKey.length < 5 ) { window.alert( 'The key must be at least 5 characters long' ); return oString; }
	var oKeyNum = new Array(), oOutStr = oString.split( 'O.O' ), oOutStr2 = '', oOp = new Array('-=','*=','+=','/= 0.01 *');
	for( var x = 0; x < oKey.length; x++ ) { oKeyNum[x] = parseInt( '0x' + completeEscape( oKey.charAt( x ) ) ); }
	for( var x = 0; x < oOutStr.length; x++ ) {
		oOutStr[x] = parseFloat( oOutStr[x] ); //otherwise, if the first operator is +, it will just append
		for( var z = oKey.length - 1; z >= 0; z-- ) { eval( 'oOutStr[x] ' + oOp[z % 4] + ' ' + oKeyNum[z] + ';' ); }
		oOutStr[x] = decToHex( Math.round( oOutStr[x] ) );
	}
	oOutStr = oOutStr.join( '' );
	for( x = 0; x < oOutStr.length; x += 2 ) { oOutStr2 += unescape( '%' + oOutStr.substr( x, 2 ) ); }
	return oOutStr2;
}

function decToHex(oNum) { //function to convert decimal to hex
	var hexChars = new Array('0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'), outP = '',d;
	for( var x = oNum; x > 0; x = ( x - ( x % 16 ) ) / 16 ) {
		outP = hexChars[x % 16] + '' + outP;
	}
	if( outP.length % 2 ) { outP = '0' + outP; } return outP;
}