cryptpad/www/common/curve.js

define([
    '/bower_components/tweetnacl/nacl-fast.min.js',
], function () {
    var Nacl = window.nacl;
    var Curve = {};

    // nacl.box(message, nonce, theirPublicKey, mySecretKey)
    Curve.encrypt = function (message, theirPub, mySecret) {
        var buffer = Nacl.util.decodeUTF8(message);
        var nonce = Nacl.randomBytes(24);
        var box = Nacl.box(buffer, nonce, theirPub, mySecret);
        return Nacl.util.encodeBase64(nonce) + '|' + Nacl.util.encodeBase64(box);
    };

    // nacl.box.open(box, nonce, theirPublicKey, mySecretKey)
    Curve.decrypt = function (packed, theirPub, mySecret) {
        var unpacked = packed.split('|');
        var nonce = Nacl.util.decodeBase64(unpacked[0]);
        var box = Nacl.util.decodeBase64(unpacked[1]);
        var message = Nacl.box.open(box, nonce, theirPub, mySecret);
        return Nacl.util.encodeUTF8(message);
    };

    Curve.createEncryptor = function (theirPublic, mySecret) {
        var theirs = Nacl.util.decodeBase64(theirPublic);
        var mine = Nacl.util.decodeBase64(mySecret);
        return {
            encrypt: function (msg) {
                return Curve.encrypt(msg, theirs, mine);
            },
            decrypt: function (packed) {
                return Curve.decrypt(packed, theirs, mine);
            }
        };
    };

    return Curve;
});