cryptocontext.h

MiniSip Client with DomainKeys Authentication, Sip, Audio communications, Echo Cancel

/*
 Copyright (C) 2004-2006 the Minisip Team
 
 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 this library; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

/* Copyright (C) 2004 
 *
 * Authors: Israel Abad <[e-mail]>
 *          Erik Eliasson <[e-mail]>
 *          Johan Bilien <[e-mail]>
 *	    Joachim Orrblad <[e-mail]>
*/


#ifndef CRYPTOCONTEXT_H
#define CRYPTOCONTEXT_H

#include<libminisip/libminisip_config.h>

#include<libmcrypto/aes.h>
#include<libmcrypto/hmac.h>
#include<libmutil/MemObject.h>

#include<libminisip/rtp/RtpPacket.h>

#define REPLAY_WINDOW_SIZE 64

class LIBMINISIP_API CryptoContext : public MObject{
	public:
		CryptoContext( uint32_t ssrc );
		
		CryptoContext( uint32_t ssrc, int roc, uint16_t seq_no,
			        int key_deriv_rate,
				//enum encr_method encryption, 
				uint8_t ealg, 
				//enum auth_method authentication,
				uint8_t aalg,
				unsigned char * master_key,
				unsigned int master_key_length,
				unsigned char * master_salt,
				unsigned int master_salt_length,
				uint8_t ekeyl, 
				uint8_t akeyl,
				uint8_t skeyl,
				uint8_t encr, 
				uint8_t auth,
				uint8_t tag_length );
		~CryptoContext();
		
		void set_roc( unsigned int roc );
		unsigned int get_roc();

		void rtp_encrypt( RtpPacket * rtp, uint64_t index );
		void rtp_authenticate( RtpPacket * rtp, uint32_t roc, 
				unsigned char * tag );
		void derive_srtp_keys( uint64_t index );
		uint64_t guess_index( unsigned short new_seq_nb );
		bool check_replay( unsigned short new_seq_nb );
		void update( unsigned short new_seq_nb );

		int get_tag_length();
		int get_mki_length();

		virtual std::string getMemObjectType(){return "CryptoContext";};

		uint32_t getSsrc();

	private:

		uint32_t ssrc;
		bool using_mki;
		unsigned int mki_length;
		unsigned char * mki;

		unsigned int roc;
		unsigned int guessed_roc;
		unsigned short s_l;
		unsigned int key_deriv_rate;

		/* bitmask for replay check */
		uint64_t replay_window;

		unsigned char * master_key;
		unsigned int master_key_length;
		unsigned int master_key_srtp_use_nb;
		unsigned int master_key_srtcp_use_nb;
		unsigned char * master_salt;
		unsigned int master_salt_length;
		
		/* Session Encryption, Authentication keys, Salt */
		int n_e;
		unsigned char * k_e;
		int n_a;
		unsigned char * k_a;
		int n_s;
		unsigned char * k_s;
		
		//enum encr_method encryption;
		//enum auth_method authentication;
		uint8_t ealg;
		uint8_t aalg;
		uint8_t ekeyl;
		uint8_t akeyl;
		uint8_t skeyl;
		uint8_t encr;
		uint8_t auth;
		uint8_t tag_length;
};

#endif