decrypt.js

#! /usr/bin/env node

var fs = require("fs");



var argv = process.argv;

//                     4556454e54484f52495a4f4e
//                     0617071EE10C9F5B
var key1 = new Buffer("FFD8FFE000104A464946004556454E54", "hex");
var key2str;
var key2str_1 = key2str = "HORIZON EVENT";
var key2 = new Buffer(key2str);
//var key4 = new Buffer("480617071EE10C9F5B0000000000", "hex");
var key4 = new Buffer("480617071EE10C9F5B0000000000", "hex");

var key = Buffer.concat([key1, key2]);
//var key = new Buffer("ENT HORIZONEV");

var shift = 0;

var data = (argv[2] && new Buffer(argv[2].replace(/[^0-9a-f]/gi, ""), "hex")) || fs.readFileSync("masked_key.png");
//var data = new Buffer("4F52495A4F4EFFD9", "hex");
//var key = new Buffer("49454E44AE426082", "hex");

var newData = new Buffer(data.length);

while((key.length <= 50)){
	key = Buffer.concat([key, (new Buffer(key2str_1))]);
}
/*
while(key.length % 8 != 0){
	key = Buffer.concat([key, (new Buffer([0]))]);
}
*/

key = new Buffer("ffd8ffe000104a464946004556454e54484f52495a4f4e204556454e54484f52495a4f4e204556454e54484f52495a4f4e204556454e54484F52495A4F4EFFD9", "hex");
//484F52495A4F4EFFD9

//key = key.slice(0, 58);

while(newData[0xEFFF8] != 0x49){
	for(var i = 0; i < data.length; i++){
		newData[i] = data[i] ^ key[i % key.length];
	}
	break;
	if(argv[2]){
		break;
	}
}
console.log(key.length.toString(10));
console.log(key.toString("hex"));

if(argv[2]){
	console.log(newData);
	console.log(newData.toString("hex").toUpperCase());
	console.log(encodeURIComponent(newData.toString()));
}else{
	fs.writeFileSync("out.png", newData);
}
//console.log(newData.toString("hex").toUpperCase());

//4F 52 49 5A 4F 4E FF D9
//49 45 4E 44 AE 42 60 82

steg.js

#! /usr/bin/env node

var pngparse = require("pngparse");

var argv = process.argv;

//                     4556454e54484f52495a4f4e
//                     0617071EE10C9F5B
/*
var key1 = new Buffer("FFD8FFE000104A464946004556454E54", "hex");
var key2str;
var key2str_1 = key2str = "HORIZON EVENT";
var key2 = new Buffer(key2str);
var key4 = new Buffer("480617071EE10C9F5B", "hex");
var key = (argv[3] && new Buffer(argv[3].replace(/[^0-9a-f]/gi, ""), "hex")) || Buffer.concat([key1, key2, key4]);

var shift = 0;
*/

//var data = (argv[2] && new Buffer(argv[2].replace(/[^0-9a-f]/gi, ""), "hex")) || fs.readFileSync("steg.png");
//var data = new Buffer("4F52495A4F4EFFD9", "hex");
//var key = new Buffer("49454E44AE426082", "hex");

var newData = new Buffer(200);
newData.fill(0);
pngparse.parseFile("steg.png", function(err, file){
	var data = file.data;
	var i2 = 0;
	for(var i = 0; i < newData.length * 8; i++){
		if((i+1) % 4){
			newData[(i2 / 8) >>> 0] |= (data[i] & 1) << (7 - (i2 % 8));
			i2++
		}
	}
	console.log(newData);
	console.log(newData.toString("hex").toUpperCase());
	console.log(escape(newData.toString()));
});
	
//console.log(newData.toString("hex").toUpperCase());

//4F 52 49 5A 4F 4E FF D9
//49 45 4E 44 AE 42 60 82