/*
    @shortdesc Javascript functions to encrypt / decrypt protected data
    @public
    @author Gauthier de Valensart, (mail: cfr website : http://www.ioswebdesign.com)
    @version 0.01b1
    @date 2007-January-07
    
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
    FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
    COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
    IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
    CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

/* Usefull functions */
function e(d)
{
	return document.getElementById(d);
}

function validate()
	{
		var k = document.getElementById('key').value.toUpperCase();
		var r = md5(k);
		var result = alphac(s, k, r, false);
		
		if(k == result)
		{
			while(c.length % 4 != 0)
			{
				c += '=';
			}
			c = alphac(c, k, r, false);
			d = decodeBase64(c);
			document.getElementById('protectedData').innerHTML = d;
		}
		else
		{
			alert('Code incorrect. Merci d\'essayer à nouveau.');	
			return false;
		}
	}
	
function input(i,c)
{
	if(i.value.length >= 5 && c != 13) validate();	
}

/* Alphac functions by Joseph Myers : http://www.myersdaily.org/joseph/javascript/alphac.html */

c64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'.split(''), l64 = {};
for (i=0; i<64; i++)
l64[c64[i]] = i;

function alphar(s) {
// I only pray--let me be ready.
var i;
// s must contain only base-64 characters!
s = s.replace(/[^0-9A-Za-z+\/]+/g, '');
s = s.split('');
// preparse k into n-series
for (i=0; i<s.length; i++)
s[i] = l64[s[i]];
return s;
}

// circular--acraw(acraw(a, k, r, sec), k, r, sec) == a
function acraw(s, k, r, seed) {
/* seed is a sec feature;
read some papers about non-repeated initializations */
var i;
s = s.split('');
// isn't it thrilling?
for (i=0; i<s.length; i++)
s[i] = c64[l64[s[i]] ^ k[i%k.length] ^ r[i%r.length] ^ seed];
return s.join(''); // yahoo!
}

function alphac(s, k, r, on) { /* encrypt = on | off */
// get read, get set
var d, i; k=alphar(k), r=alphar(r);
// dump empty stuff
if (r.length == 0 || k.length == 0 || s.length == 0) return s;
// split s into bunches of base-64/non-base-64
s = s.match(/[^0-9A-Za-z+\/]+|[0-9A-Za-z+\/]+/g);
i = /[0-9A-Za-z+\/]/.test(s[0]) ? 0 : 1;
// give a 1-2 punch! go!
if (on)
for (; i<s.length; i+=2)
d = c64[Math.floor(Math.random()*64)],
s[i] = acraw(s[i], k, r, l64[d])+d; /* si + d, Sidney Hall */
else
for (; i<s.length; i+=2)
d = s[i].length-1,
s[i] = acraw(s[i].substring(0, d), k, r, l64[s[i].charAt(d)]);
// finished!
return s.join('');
}

/* BASE 64 function from http://ostermiller.org/calc/encode.html */

var END_OF_INPUT = -1;

var base64Chars = new Array(
    'A','B','C','D','E','F','G','H',
    'I','J','K','L','M','N','O','P',
    'Q','R','S','T','U','V','W','X',
    'Y','Z','a','b','c','d','e','f',
    'g','h','i','j','k','l','m','n',
    'o','p','q','r','s','t','u','v',
    'w','x','y','z','0','1','2','3',
    '4','5','6','7','8','9','+','/'
);

var reverseBase64Chars = new Array();
for (var i=0; i < base64Chars.length; i++){
    reverseBase64Chars[base64Chars[i]] = i;
}

var base64Str;
var base64Count;

function setBase64Str(str){
    base64Str = str;
    base64Count = 0;
}
function readBase64(){    
    if (!base64Str) return END_OF_INPUT;
    if (base64Count >= base64Str.length) return END_OF_INPUT;
    var c = base64Str.charCodeAt(base64Count) & 0xff;
    base64Count++;
    return c;
}

function encodeBase64(str){
    setBase64Str(str);
    var result = '';
    var inBuffer = new Array(3);
    var lineCount = 0;
    var done = false;
    while (!done && (inBuffer[0] = readBase64()) != END_OF_INPUT){
        inBuffer[1] = readBase64();
        inBuffer[2] = readBase64();
        result += (base64Chars[ inBuffer[0] >> 2 ]);
        if (inBuffer[1] != END_OF_INPUT){
            result += (base64Chars [(( inBuffer[0] << 4 ) & 0x30) | (inBuffer[1] >> 4) ]);
            if (inBuffer[2] != END_OF_INPUT){
                result += (base64Chars [((inBuffer[1] << 2) & 0x3c) | (inBuffer[2] >> 6) ]);
                result += (base64Chars [inBuffer[2] & 0x3F]);
            } else {
                result += (base64Chars [((inBuffer[1] << 2) & 0x3c)]);
                result += ('=');
                done = true;
            }
        } else {
            result += (base64Chars [(( inBuffer[0] << 4 ) & 0x30)]);
            result += ('=');
            result += ('=');
            done = true;
        }
        lineCount += 4;
        if (lineCount >= 76){
            result += ('\n');
            lineCount = 0;
        }
    }
    return result;
}

function readReverseBase64(){   
    if (!base64Str) return END_OF_INPUT;
    while (true){      
        if (base64Count >= base64Str.length) return END_OF_INPUT;
        var nextCharacter = base64Str.charAt(base64Count);
        base64Count++;
        if (reverseBase64Chars[nextCharacter]){
            return reverseBase64Chars[nextCharacter];
        }
        if (nextCharacter == 'A') return 0;
    }
    return END_OF_INPUT;
}

function ntos(n){
    n=n.toString(16);
    if (n.length == 1) n="0"+n;
    n="%"+n;
    return unescape(n);
}

function decodeBase64(str){
    setBase64Str(str);
    var result = "";
    var inBuffer = new Array(4);
    var done = false;
    while (!done && (inBuffer[0] = readReverseBase64()) != END_OF_INPUT
        && (inBuffer[1] = readReverseBase64()) != END_OF_INPUT){
        inBuffer[2] = readReverseBase64();
        inBuffer[3] = readReverseBase64();
        result += ntos((((inBuffer[0] << 2) & 0xff)| inBuffer[1] >> 4));
        if (inBuffer[2] != END_OF_INPUT){
            result +=  ntos((((inBuffer[1] << 4) & 0xff)| inBuffer[2] >> 2));
            if (inBuffer[3] != END_OF_INPUT){
                result +=  ntos((((inBuffer[2] << 6)  & 0xff) | inBuffer[3]));
            } else {
                done = true;
            }
        } else {
            done = true;
        }
    }
    return result;
}

/* Md5 functions from MD5 code (md5.js) by Joseph Myers is based on md5.js by Paul Johnston and Greg Holt.*/
function md5cycle(x, k) {
var a = x[0], b = x[1], c = x[2], d = x[3];

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

a = gg(a, b, c, d, k[1], 5, -165796510);
d = gg(d, a, b, c, k[6], 9, -1069501632);
c = gg(c, d, a, b, k[11], 14,  643717713);
b = gg(b, c, d, a, k[0], 20, -373897302);
a = gg(a, b, c, d, k[5], 5, -701558691);
d = gg(d, a, b, c, k[10], 9,  38016083);
c = gg(c, d, a, b, k[15], 14, -660478335);
b = gg(b, c, d, a, k[4], 20, -405537848);
a = gg(a, b, c, d, k[9], 5,  568446438);
d = gg(d, a, b, c, k[14], 9, -1019803690);
c = gg(c, d, a, b, k[3], 14, -187363961);
b = gg(b, c, d, a, k[8], 20,  1163531501);
a = gg(a, b, c, d, k[13], 5, -1444681467);
d = gg(d, a, b, c, k[2], 9, -51403784);
c = gg(c, d, a, b, k[7], 14,  1735328473);
b = gg(b, c, d, a, k[12], 20, -1926607734);

a = hh(a, b, c, d, k[5], 4, -378558);
d = hh(d, a, b, c, k[8], 11, -2022574463);
c = hh(c, d, a, b, k[11], 16,  1839030562);
b = hh(b, c, d, a, k[14], 23, -35309556);
a = hh(a, b, c, d, k[1], 4, -1530992060);
d = hh(d, a, b, c, k[4], 11,  1272893353);
c = hh(c, d, a, b, k[7], 16, -155497632);
b = hh(b, c, d, a, k[10], 23, -1094730640);
a = hh(a, b, c, d, k[13], 4,  681279174);
d = hh(d, a, b, c, k[0], 11, -358537222);
c = hh(c, d, a, b, k[3], 16, -722521979);
b = hh(b, c, d, a, k[6], 23,  76029189);
a = hh(a, b, c, d, k[9], 4, -640364487);
d = hh(d, a, b, c, k[12], 11, -421815835);
c = hh(c, d, a, b, k[15], 16,  530742520);
b = hh(b, c, d, a, k[2], 23, -995338651);

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

x[0] = add32(a, x[0]);
x[1] = add32(b, x[1]);
x[2] = add32(c, x[2]);
x[3] = add32(d, x[3]);

}

function cmn(q, a, b, x, s, t) {
a = add32(add32(a, q), add32(x, t));
return add32((a << s) | (a >>> (32 - 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);
}

function md51(s) {
txt = '';
var n = s.length,
state = [1732584193, -271733879, -1732584194, 271733878], i;
for (i=64; i<=s.length; i+=64) {
md5cycle(state, md5blk(s.substring(i-64, i)));
}
s = s.substring(i-64);
var tail = [0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0];
for (i=0; i<s.length; i++)
tail[i>>2] |= s.charCodeAt(i) << ((i%4) << 3);
tail[i>>2] |= 0x80 << ((i%4) << 3);
if (i > 55) {
md5cycle(state, tail);
for (i=0; i<16; i++) tail[i] = 0;
}
tail[14] = n*8;
md5cycle(state, tail);
return state;
}

/* there needs to be support for Unicode here,
 * unless we pretend that we can redefine the MD-5
 * algorithm for multi-byte characters (perhaps
 * by adding every four 16-bit characters and
 * shortening the sum to 32 bits). Otherwise
 * I suggest performing MD-5 as if every character
 * was two bytes--e.g., 0040 0025 = @%--but then
 * how will an ordinary MD-5 sum be matched?
 * There is no way to standardize text to something
 * like UTF-8 before transformation; speed cost is
 * utterly prohibitive. The JavaScript standard
 * itself needs to look at this: it should start
 * providing access to strings as preformed UTF-8
 * 8-bit unsigned value arrays.
 */
function md5blk(s) { /* I figured global was faster.   */
var md5blks = [], i; /* Andy King said do it this way. */
for (i=0; i<64; i+=4) {
md5blks[i>>2] = s.charCodeAt(i)
+ (s.charCodeAt(i+1) << 8)
+ (s.charCodeAt(i+2) << 16)
+ (s.charCodeAt(i+3) << 24);
}
return md5blks;
}

var hex_chr = '0123456789abcdef'.split('');

function rhex(n)
{
var s='', j=0;
for(; j<4; j++)
s += hex_chr[(n >> (j * 8 + 4)) & 0x0F]
+ hex_chr[(n >> (j * 8)) & 0x0F];
return s;
}

function hex(x) {
for (var i=0; i<x.length; i++)
x[i] = rhex(x[i]);
return x.join('');
}

function md5(s) {
return hex(md51(s));
}

/* this function is much faster,
so if possible we use it. Some IEs
are the only ones I know of that
need the idiotic second function,
generated by an if clause.  */

function add32(a, b) {
return (a + b) & 0xFFFFFFFF;
}

if (md5('hello') != '5d41402abc4b2a76b9719d911017c592') {
function add32(x, y) {
var lsw = (x & 0xFFFF) + (y & 0xFFFF),
msw = (x >> 16) + (y >> 16) + (lsw >> 16);
return (msw << 16) | (lsw & 0xFFFF);
}
}