/*
 * A JavaScript implementation of the RSA Data Security, Inc. MD5 Message
 * Digest Algorithm, as defined in RFC 1321.
 */

/*
 * Convert a 32-bit number to a hex string with ls-byte first
 */
var hex_chr = "0123456789abcdef";
function rhex(num) {
	str = "";
	for(j = 0; j <= 3; j++)
		str += hex_chr.charAt((num >> (j * 8 + 4)) & 0x0F) + hex_chr.charAt((num >> (j * 8)) & 0x0F);
	return str;
}

/*
 * Convert a string to a sequence of 16-word blocks, stored as an array.
 * Append padding bits and the length, as described in the MD5 standard.
 */
function str2blks_MD5(str) {
	nblk = ((str.length + 8) >> 6) + 1;
	blks = new Array(nblk * 16);
	for(i = 0; i < nblk * 16; i++) blks[i] = 0;
	for(i = 0; i < str.length; i++)
		blks[i >> 2] |= str.charCodeAt(i) << ((i % 4) * 8);
	blks[i >> 2] |= 0x80 << ((i % 4) * 8);
	blks[nblk * 16 - 2] = str.length * 8;
	return blks;
}

/*
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally 
 * to work around bugs in some JS interpreters.
 */
function add(x, y) {
	var lsw = (x & 0xFFFF) + (y & 0xFFFF);
	var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
	return (msw << 16) | (lsw & 0xFFFF);
}

/*
 * Bitwise rotate a 32-bit number to the left
 */
function rol(num, cnt) {
	return (num << cnt) | (num >>> (32 - cnt));
}

/*
 * These functions implement the basic operation for each round of the
 * algorithm.
 */
function cmn(q, a, b, x, s, t) {
	return add(rol(add(add(a, q), add(x, t)), s), b);
}
function ff(a, b, c, d, x, s, t) {
	return cmn((b & c) | ((~b) & d), a, b, x, s, t);
}
function gg(a, b, c, d, x, s, t) {
	return cmn((b & d) | (c & (~d)), a, b, x, s, t);
}
function hh(a, b, c, d, x, s, t) {
	return cmn(b ^ c ^ d, a, b, x, s, t);
}
function ii(a, b, c, d, x, s, t) {
	return cmn(c ^ (b | (~d)), a, b, x, s, t);
}

/*
 * Take a string and return the hex representation of its MD5.
 */
function MD5(str) {
	x = str2blks_MD5(str);
	var a =  1732584193;
	var b = -271733879;
	var c = -1732584194;
	var d =  271733878;
 
	for(i = 0; i < x.length; i += 16) {
		var olda = a;
		var oldb = b;
		var oldc = c;
		var oldd = d;

		a = ff(a, b, c, d, x[i+ 0], 7 , -680876936);
		d = ff(d, a, b, c, x[i+ 1], 12, -389564586);
		c = ff(c, d, a, b, x[i+ 2], 17,  606105819);
		b = ff(b, c, d, a, x[i+ 3], 22, -1044525330);
		a = ff(a, b, c, d, x[i+ 4], 7 , -176418897);
		d = ff(d, a, b, c, x[i+ 5], 12,  1200080426);
		c = ff(c, d, a, b, x[i+ 6], 17, -1473231341);
		b = ff(b, c, d, a, x[i+ 7], 22, -45705983);
		a = ff(a, b, c, d, x[i+ 8], 7 ,  1770035416);
		d = ff(d, a, b, c, x[i+ 9], 12, -1958414417);
		c = ff(c, d, a, b, x[i+10], 17, -42063);
		b = ff(b, c, d, a, x[i+11], 22, -1990404162);
		a = ff(a, b, c, d, x[i+12], 7 ,  1804603682);
		d = ff(d, a, b, c, x[i+13], 12, -40341101);
		c = ff(c, d, a, b, x[i+14], 17, -1502002290);
		b = ff(b, c, d, a, x[i+15], 22,  1236535329);    

		a = gg(a, b, c, d, x[i+ 1], 5 , -165796510);
		d = gg(d, a, b, c, x[i+ 6], 9 , -1069501632);
		c = gg(c, d, a, b, x[i+11], 14,  643717713);
		b = gg(b, c, d, a, x[i+ 0], 20, -373897302);
		a = gg(a, b, c, d, x[i+ 5], 5 , -701558691);
		d = gg(d, a, b, c, x[i+10], 9 ,  38016083);
		c = gg(c, d, a, b, x[i+15], 14, -660478335);
		b = gg(b, c, d, a, x[i+ 4], 20, -405537848);
		a = gg(a, b, c, d, x[i+ 9], 5 ,  568446438);
		d = gg(d, a, b, c, x[i+14], 9 , -1019803690);
		c = gg(c, d, a, b, x[i+ 3], 14, -187363961);
		b = gg(b, c, d, a, x[i+ 8], 20,  1163531501);
		a = gg(a, b, c, d, x[i+13], 5 , -1444681467);
		d = gg(d, a, b, c, x[i+ 2], 9 , -51403784);
		c = gg(c, d, a, b, x[i+ 7], 14,  1735328473);
		b = gg(b, c, d, a, x[i+12], 20, -1926607734);
    
		a = hh(a, b, c, d, x[i+ 5], 4 , -378558);
		d = hh(d, a, b, c, x[i+ 8], 11, -2022574463);
		c = hh(c, d, a, b, x[i+11], 16,  1839030562);
		b = hh(b, c, d, a, x[i+14], 23, -35309556);
		a = hh(a, b, c, d, x[i+ 1], 4 , -1530992060);
		d = hh(d, a, b, c, x[i+ 4], 11,  1272893353);
		c = hh(c, d, a, b, x[i+ 7], 16, -155497632);
		b = hh(b, c, d, a, x[i+10], 23, -1094730640);
		a = hh(a, b, c, d, x[i+13], 4 ,  681279174);
		d = hh(d, a, b, c, x[i+ 0], 11, -358537222);
		c = hh(c, d, a, b, x[i+ 3], 16, -722521979);
		b = hh(b, c, d, a, x[i+ 6], 23,  76029189);
		a = hh(a, b, c, d, x[i+ 9], 4 , -640364487);
		d = hh(d, a, b, c, x[i+12], 11, -421815835);
		c = hh(c, d, a, b, x[i+15], 16,  530742520);
		b = hh(b, c, d, a, x[i+ 2], 23, -995338651);

		a = ii(a, b, c, d, x[i+ 0], 6 , -198630844);
		d = ii(d, a, b, c, x[i+ 7], 10,  1126891415);
		c = ii(c, d, a, b, x[i+14], 15, -1416354905);
		b = ii(b, c, d, a, x[i+ 5], 21, -57434055);
		a = ii(a, b, c, d, x[i+12], 6 ,  1700485571);
		d = ii(d, a, b, c, x[i+ 3], 10, -1894986606);
		c = ii(c, d, a, b, x[i+10], 15, -1051523);
		b = ii(b, c, d, a, x[i+ 1], 21, -2054922799);
		a = ii(a, b, c, d, x[i+ 8], 6 ,  1873313359);
		d = ii(d, a, b, c, x[i+15], 10, -30611744);
		c = ii(c, d, a, b, x[i+ 6], 15, -1560198380);
		b = ii(b, c, d, a, x[i+13], 21,  1309151649);
		a = ii(a, b, c, d, x[i+ 4], 6 , -145523070);
		d = ii(d, a, b, c, x[i+11], 10, -1120210379);
		c = ii(c, d, a, b, x[i+ 2], 15,  718787259);
		b = ii(b, c, d, a, x[i+ 9], 21, -343485551);

		a = add(a, olda);
		b = add(b, oldb);
		c = add(c, oldc);
		d = add(d, oldd);
	}
	return rhex(a) + rhex(b) + rhex(c) + rhex(d);
}

function valid_js() {
	/*
	// anything that claims NS 4 or higher functionality better work 
	if (navigator.userAgent.indexOf("Mozilla/") == 0) {
		return (parseInt(navigator.appVersion) >= 4);
	}
	return false;
	*/
	return true;
}
 
function hash(form,login_url) {
	
	// this is Javascript enabled browser
	//document.login_form[".js"].value=1;
	// rudimentary check for a 4.x brower. should catch IE4+ and NS4.*
	var url;

	if (arguments.length > 1 && login_url != "") { // in case login_url is not passed in
		url = login_url;
	} else {
		url = "login.php";
	}
	url += "?";
      
	if (valid_js()) {
		var passwd = form.passwd.value;
		var hash1 = MD5(form.passwd.value);
		var challenge = form[".challenge"].value;
		var hash2 = MD5(form.passwd.value) + challenge;
		var hash;
		if(form.passwd.value) {
			hash=MD5(hash2);
		} else {
			hash="";
		}
		var js = 0;

		for(i=0; i< form.elements.length; i++) {
			if(form.elements[i].name.length <=0) {
				continue;
			}
			if(i > 0) {
				url += "&";
			}
			url += form.elements[i].name;
			url += "=";
			if(form.elements[i].name == "passwd") {
				url += hash;
			} else if (form.elements[i].type == "checkbox" && !form.elements[i].checked) {
				url += "";
			} else if (form.elements[i].type == "radio" && !form.elements[i].checked) {
				url += "";
			} else if (form.elements[i].name == ".save"){
				url += "1"; // "Sign in" causes problem with the space
			} else if (form.elements[i].name == ".js"){
				js = 1;
				url += "1"; 
			} else {
				url += escape(form.elements[i].value);
			}
		}
		// indicate the password is hashed.
		url += "&.hash=1";
		if(js == 0){
			url += "&.js=1";
		}
		url += "&.md5=1";
		location.href=url;
		// prevent from running this again. Allow the server response to submit the form directly
		form.onsubmit=null;
		// abort normal form submission
		return false;
	}
	// allow normal form submission
	return true;
}