/*
  Copyright (C) 2013 Grégory Soutadé
  
  This file is part of gPass.
  
  gPass 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 3 of the License, or
  (at your option) any later version.
  
  gPass 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 gPass.  If not, see <http://www.gnu.org/licenses/>.
*/

var {Cc, Ci} = require("chrome");

var hmac = Cc["@mozilla.org/security/hmac;1"]
    .createInstance(Ci.nsICryptoHMAC);

exports.hmac = {
    hmac_init : function (key) {
	var keyObject = Cc["@mozilla.org/security/keyobjectfactory;1"]
            .getService(Ci.nsIKeyObjectFactory)
            .keyFromString(Ci.nsIKeyObject.HMAC, key);
	hmac.init(hmac.SHA256, keyObject);
    },

    hmac_digest : function (message) {
	var data = new Uint8Array(message.length);
	for(i=0; i<message.length; i++)
	    data[i] = message.charCodeAt(i);
	hmac.update(data, data.length);
	res = hmac.finish(false);
	hmac.reset();
	return res;
    }
};