One Time Pad

by mifeng

HTML

http://travisdazell.blogspot.hk/2012/11/many-time-pad-attack-crib-drag.html

JavaScript

function toHex(text) {
    return text.split("").map(function(c) {
        return c.charCodeAt().toString(16);
    }).join("");
}

function toASCII(hex) {
    return hex.match(/../g).map(function(h) {
        return String.fromCharCode(parseInt(h, 16));
    }).join("");
}

function xor(h1, h2) {
    var result = "";
    for (var i = 0; i < h1.length; i += 2) {
        var h1c = h1.slice(i, i + 2),
            h2c = h2.slice(i % h2.length, (i + 2) % (h2.length + 2)),
            xor = parseInt(h1c, 16) ^ parseInt(h2c, 16);
        
        result += ("0" + xor.toString(16)).slice(-2);
    }
    return result;
}

//var guess = " YOU WOULD HAVE THEM DO UNTO YOU";
//var guess = "NS OUT THAT MAKING THESE CHALLENGES IS VERY DIFFICULT.";
var guess = "QUOTE: DO UNTO OTHERS AS YOU WOULD HAVE THEM DO UNTO YOU.";
var key = "It's the eye of the tiger It's the thrill of the fight Ri";
var position = 0;//48; // 48
var cipher1 = "18216827654e48216f452c2b7420466f20202072274926365279062107246f212421003c29242c4c38682a2b0030274575283d28482d6f0747";
var cipher2 = "0020072775262636002a2c31003b2e61204828613f202922527401317436003720246c382d3c2e293f00263500222d3779462d2e2e3269113c";

var gh = toHex(guess);
var cc = xor(cipher1, cipher2);

console.log("===========");
console.log("cipher chars: " + cipher1.length / 2);
console.log("guess chars: " + guess.length);
console.log("guessing: " + guess);

// matching xor
function match(i) {
    var gr = xor(gh, cc.slice(i, i + gh.length));
    console.log("CHAR[" + i/2 + "]:" + toASCII(gr));
}

// brutal guess
function brutal() {
    var ALPHA = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    var POS   = 48;
    var original_guess = guess;
    
    for (var k = 0; k < ALPHA.length; k += 1) {
        
    }
}

// manual guess
function manual() {
    if (position) { match(position); }
    else {
        for (var i = 0; i <= cc.length - gh.length; i += 2) {
            match(i);
        }
    }
}

manual();