/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Doug Turner <dougt@meer.net>.
 * Portions created by the Initial Developer are Copyright (C) 2005
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Doug Turner <dougt@meer.net>
 *   Honza Bambas <honzab@firemni.cz>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsISupports.idl"
interface nsIInputStream;
interface nsIKeyObject;

/**
 * nsICryptoHMAC
 * This interface provides HMAC signature algorithms.
 */

[scriptable, uuid(8FEB4C7C-1641-4a7b-BC6D-1964E2099497)]
interface nsICryptoHMAC : nsISupports
{
    /**
     * Hashing Algorithms.  These values are to be used by the
     * |init| method to indicate which hashing function to
     * use.  These values map onto the values defined in
     * mozilla/security/nss/lib/softoken/pkcs11t.h and are 
     * switched to CKM_*_HMAC constant.
     */
    const short MD2    = 1;
    const short MD5    = 2;
    const short SHA1   = 3;
    const short SHA256 = 4;
    const short SHA384 = 5;
    const short SHA512 = 6;

    /**
     * Initialize the hashing object. This method may be
     * called multiple times with different algorithm types.
     *
     * @param aAlgorithm the algorithm type to be used.
     *        This value must be one of the above valid
     *        algorithm types.
     *
     * @param aKeyObject
     *        Object holding a key. To create the key object use for instance:
     *        var keyObject = Components.classes["@mozilla.org/security/keyobjectfactory;1"]
     *            .getService(Components.interfaces.nsIKeyObjectFactory)
     *              .keyFromString(Components.interfaces.nsIKeyObject.HMAC, rawKeyData);
     *
     * WARNING: This approach is not FIPS compliant.
     *
     * @throws NS_ERROR_INVALID_ARG if an unsupported algorithm
     *        type is passed.
     *
     * NOTE: This method must be called before any other method 
     *        on this interface is called.
     */
    void init(in unsigned long aAlgorithm, in nsIKeyObject aKeyObject);

    /**
     * @param aData a buffer to calculate the hash over
     *
     * @param aLen the length of the buffer |aData|
     *
     * @throws NS_ERROR_NOT_INITIALIZED if |init| has not been 
     *         called.
     */
    void update([const, array, size_is(aLen)] in octet aData, in unsigned long aLen);

    /**
     * Calculates and updates a new hash based on a given data stream.
     *
     * @param aStream an input stream to read from.
     *
     * @param aLen how much to read from the given |aStream|.  Passing
     *        PR_UINT32_MAX indicates that all data available will be used 
     *        to update the hash. 
     *
     * @throws NS_ERROR_NOT_INITIALIZED if |init| has not been 
     *         called.
     *
     * @throws NS_ERROR_NOT_AVAILABLE if the requested amount of 
     *         data to be calculated into the hash is not available.
     *
     */
    void updateFromStream(in nsIInputStream aStream, in unsigned long aLen);
    
    /**
     * Completes this HMAC object and produces the actual HMAC diegest data.
     *
     * @param aASCII if true then the returned value is a base-64 
     *        encoded string.  if false, then the returned value is
     *        binary data.  
     *
     * @return a hash of the data that was read by this object.  This can
     *         be either binary data or base 64 encoded.
     *
     * @throws NS_ERROR_NOT_INITIALIZED if |init| has not been 
     *         called.
     *
     * NOTE: This method may be called any time after |init|
     *       is called.  This call resets the object to its
     *       pre-init state.
     */
    ACString finish(in PRBool aASCII);

    /**
     * Reinitialize HMAC context to be reused with the same
     * settings (the key and hash algorithm) but on different 
     * set of data.
     */
    void reset();
};