CryptoContextCtrl.h

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/*
  Copyright (C) 2004-2006 the Minisip Team
  Copyright (C) 2011 Werner Dittmann for the SRTCP support
  
  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with GNU ccRTP.  If not, see <http://www.gnu.org/licenses/>.
*/



#ifndef CRYPTOCONTEXTCTRL_H
#define CRYPTOCONTEXTCTRL_H

#include <commoncpp/config.h>

#define REPLAY_WINDOW_SIZE 64

#ifdef SRTP_SUPPORT
#include <ccrtp/crypto/SrtpSymCrypto.h>
#endif

NAMESPACE_COMMONCPP

    class __EXPORT CryptoContextCtrl {
    public:
    CryptoContextCtrl( uint32 ssrc );

    CryptoContextCtrl( uint32 ssrc,
               const  int32 ealg,
               const  int32 aalg,
               uint8* masterKey,
               int32  masterKeyLength,
               uint8* masterSalt,
               int32  masterSaltLength,
               int32  ekeyl,
               int32  akeyl,
               int32  skeyl,
               int32  tagLength );
    ~CryptoContextCtrl();

    void srtcpEncrypt( uint8* rtp, size_t len, uint64 index, uint32 ssrc );

    void srtcpAuthenticate(uint8* rtp, size_t len, uint32 roc, uint8* tag );

     void deriveSrtcpKeys();

     bool checkReplay(uint32 newSeqNumber);

    void update( uint32 newSeqNumber );

    inline int32
    getTagLength() const
        {return tagLength;}


    inline int32
    getMkiLength() const
        {return mkiLength;}

    inline uint32
    getSsrc() const
        {return ssrcCtx;}

    CryptoContextCtrl* newCryptoContextForSSRC(uint32 ssrc);

    private:

        uint32 ssrcCtx;
        bool   using_mki;
        uint32 mkiLength;
        uint8* mki;

        uint32 s_l;

        /* bitmask for replay check */
        uint64 replay_window;

        uint8* master_key;
        uint32 master_key_length;
        uint8* master_salt;
        uint32 master_salt_length;

        /* Session Encryption, Authentication keys, Salt */
        int32  n_e;
        uint8* k_e;
        int32  n_a;
        uint8* k_a;
        int32  n_s;
        uint8* k_s;

        int32 ealg;
        int32 aalg;
        int32 ekeyl;
        int32 akeyl;
        int32 skeyl;
        int32 tagLength;

        void*   macCtx;

#ifdef SRTP_SUPPORT
        SrtpSymCrypto* cipher;
        SrtpSymCrypto* f8Cipher;
#else
        void* cipher;
        void* f8Cipher;
#endif

    };

END_NAMESPACE

#endif

---