Script

function getRandom( min, max ) {
        if( min > max ) {
                return( -1 );
        }
        if( min == max ) {
                return( min );
        }

    return( min + parseInt( Math.random() * ( max-min+1 ) ) );
}

/*
  Synchronous xmlHttpRequest/POST:
*/
function xmlhttpPost(url, params) {
        var xmlHttp = null;
        try {
            // Mozilla, Opera, Safari sowie Internet Explorer (ab v7)
            xmlHttp = new XMLHttpRequest();
        } catch(e) {
            try {
                // MS Internet Explorer (ab v6)
                xmlHttp  = new ActiveXObject("Microsoft.XMLHTTP");
            } catch(e) {
                try {
                    // MS Internet Explorer (ab v5)
                    xmlHttp  = new ActiveXObject("Msxml2.XMLHTTP");
                } catch(e) {
                    xmlHttp  = null;
                }
            }
        }
        if (xmlHttp) {
            xmlHttp.open('POST', url, false);
                xmlHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
                xmlHttp.setRequestHeader("Content-length", params.length);
                xmlHttp.setRequestHeader("Connection", "close");
            xmlHttp.send(params);
            return xmlHttp.responseText;
        } else {
                return false;
        }

}



/*
INPUTS (Oakley Group 2)
*/
p = "FFFFFFFF"+ "FFFFFFFF"+     "C90FDAA2"+     "2168C234"+     "C4C6628B"+     "80DC1CD1"+
        "29024E08"+     "8A67CC74"+     "020BBEA6"+ "3B139B22"+ "514A0879"+     "8E3404DD"+
        "EF9519B3"+ "CD3A431B"+ "302B0A6D"+ "F25F1437"+ "4FE1356D"+ "6D51C245"+
        "E485B576"+ "625E7EC6"+ "F44C42E9"+ "A637ED6B"+ "0BFF5CB6"+ "F406B7ED"+
        "EE386BFB"+ "5A899FA5"+ "AE9F2411"+ "7C4B1FE6"+ "49286651"+ "ECE65381"+
        "FFFFFFFF"+ "FFFFFFFF";
g = "2";


function send() {
        document.getElementById("success").style.display = "none";
        msgwdw = document.getElementById("messageWindow");
        if (msgwdw == null) {
                debug = false;
        } else {
                debug = true;
        }
        frmSubject = document.getElementById("subject").value;
        frmFrom = document.getElementById("senderName").value;

        // generate random r
        randomValue = new Clipperz.ByteArray();
        iv = new Clipperz.ByteArray();
        ctr = "";
        c = (128/8)
        for (i=0; i<c ; i++) {
                randomValue.appendByte(getRandom(0, 255));
                iv.appendByte(getRandom(0, 255));
        }
        for (i = 0; i < 8; i++) {
                ctr += getRandom(48, 57)
        }

        if (debug) msgwdw.innerHTML = "<strong>Own random:</strong><br /> "+randomValue.toHexString()+"<br />";

        // calculate dhU = g^r mod p
        pB = new Clipperz.Crypto.BigInt(p,16);
        gB = new Clipperz.Crypto.BigInt(g,10);
        randomB = new Clipperz.Crypto.BigInt(randomValue.toHexString(),16);

        dhUB = gB.powerModule(randomB, pB);

        // Send dhU and reqeust dhS
        dhSx = xmlhttpPost("securecontactform_rcv_en.jsp","type=getDH&dhU="+dhUB.asString(16)+"&ctr="+ctr+"&name="+frmFrom+"&subject="+frmSubject);

        if (debug) msgwdw.innerHTML = msgwdw.innerHTML+"<strong>Sent dhU:</strong><br /> 0x"+dhUB.asString(16)+"<br />";

        // calculate k = dhS^r mod p
        dhSB = new Clipperz.Crypto.BigInt(dhSx, 16);
        dhSB = new Clipperz.Crypto.BigInt("0x"+dhSx, 16);
        if (debug) msgwdw.innerHTML = msgwdw.innerHTML+"<strong>Received dhS:</strong><br /> 0x"+dhSB.asString(16)+"<br />";

        dhB = dhSB.powerModule(randomB, pB);
        dh = "0x"+dhB.asString(16);
        if (debug) msgwdw.innerHTML = msgwdw.innerHTML+"<strong>dh:</strong><br /> 0x"+dhB.asString(16)+"<br />";

        kS = dh.substr(0,34)

        // encryypt message c = aes(m,k) (128bit, mode: ofb)
        key = new Clipperz.ByteArray(kS,16);
        if (debug) msgwdw.innerHTML = msgwdw.innerHTML+"<strong>AES key:</strong><br /> "+kS+"<br />";


        plainText = document.getElementById("message").value;
        if (debug) msgwdw.innerHTML = msgwdw.innerHTML+"<strong>Plaintext:</strong><br /> "+plainText+"<br />";

        plainByte = new Clipperz.ByteArray(plainText);
        for (i=(plainByte.length() % 16); i<16 && i != 0;i++)  {
                plainByte.appendByte("0");
        }

        numBlocks = Math.ceil(plainByte.length()/16)
        ivOrig = iv.clone();
        encPlain = new Clipperz.ByteArray();
        for (i = 0; i < numBlocks; i++) {

                iv = new Clipperz.ByteArray(
                        Clipperz.Crypto.AES.encryptBlock(new Clipperz.Crypto.AES.Key({key:key}),
                        iv.arrayValues()));

                for (j=0; j<16; j++) {
                        encPlain.appendByte(iv.byteAtIndex(j) ^ plainByte.byteAtIndex((i*16)+j));
                }
        }
        //Send encrypted message
        xmlhttpPost("securecontactform_rcv_en.jsp","type=recvMsg&msg="+encPlain.toHexString().substr(2)+"&iv="+ivOrig.toHexString().substr(2));

        if (debug) msgwdw.innerHTML = msgwdw.innerHTML+"<strong>Sent encrypted message: </strong><br />"+numBlocks+"Blocks/ "+encPlain.length()+"Bytes/ "+encPlain.toHexString()+"<br />";


        document.getElementById("success").style.display = "inline";
}