Abstract:
The present invention provides a method for providing message transmission in H.323 communication system. The method includes: the first endpoint and second endpoint confirming authentication information through a GK; according to said authentication information, the first endpoint and second endpoint exchanging message directly. Since H.235 protocol of ITU-T describes the authentication and privacy technique used in H.323 systems and provides security service for message transmission in GK-routed model, the present invention can guarantee the security of the authentication information. The functions of middle entities need not to be modified for applying the method provided by the present invention because Diffie-Hellman key exchange technology is adopted in this method. The present invention increases the network scalability of the symmetric key system by adopting negotiation mode. The present invention designates and improves the security framework of message transmission in direct-routed model of H.323 system, thereby improving the security of H.323 system.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]     This is a continuation of International Application No. PCT/CN2005/000146, which was filed on Feb. 2, 2005, and which, in turn, claimed the benefit of Chinese Patent Application No. 200410004124.3, which was filed on Feb. 7, 2004, the entire disclosures of which are hereby incorporated herein by reference. 
     
    
     BACKGROUND OF THE DISCLOSURE  
       [0002]     1. Field of the Technology  
         [0003]     The invention relates to network communication technology in general, and more specifically, to a method for providing message transmission in H.323 communication system.  
         [0004]     2. Background of the Invention  
         [0005]     In communication systems, Packet-Based Network (PBN) can not provide a guaranteed quality of service (QoS) and secure service due to technical reasons of itself, which makes PBN become a kind of network without QoS guarantee and security guarantee. The security of H.323 systems, which operate over PBN, therefore involves great concern.  
         [0006]     Generally, authentication and privacy techniques are employed by H.323 systems to provide secure services. These authentication and privacy techniques employed by H.323 systems are described in H.235 protocol of Telecommunication Standardization Sector of International Telecommunication Union (ITU-T).  
         [0007]     The H.235 protocol of ITU-T describes several security frameworks of authentication and privacy techniques for H.323 systems. At present, the security framework is in general based either on symmetric cryptosystem or on certificate with signatures. The framework based on symmetric cryptosystem, e.g., precontracted password, is simple and easy to be implemented, but the network scalability is poor, requiring that both participants of communication possess a common key in advance. The framework based on certificate with signatures has high security and strong network scalability, but it is complicated to implement and needs support of certification authority institution.  
         [0008]     As international standards, the security frameworks for H.323 systems provided by H.235 protocol of ITU-T are not described in detail hereinafter. Please refer to H.235 protocol of ITU-T to obtain detailed description.  
         [0009]     H.323 systems provide two routing modes for H.225 protocol based message transmission: Gatekeeper (GK)-routed model and direct-routed model. In the GK-routed model, H.225 protocol messages between two endpoints are transferred through GKs. In the direct-routed model, H.225 protocol messages between two terminals are exchanged directly, rather than transferred through GKs, so the direct routing mode is also referred to as non GK-routed model.  
         [0010]     All the security frameworks in H.235 protocol of ITU-T described above aim at technical schemes of security guarantee in the GK-routed model, and so far there has been no specific solution put forward for technique schemes of security guarantee in the non GK-routed model in H.235 protocol of ITU-T. Since the non GK-routed model is very important and widely used in H.323 systems, H.225 protocol message transmission in the non GK-routed model also needs security guarantee.  
       SUMMARY OF THE INVENTION  
       [0011]     The present invention provides a method for providing message transmission in H.323 communication system.  
         [0012]     The method for providing message transmission in H.323 communication system where first endpoint needs to exchange message with second endpoint includes: 
        the first endpoint and second endpoint confirming authentication information through a GK;     according to said authentication information, the first endpoint and second endpoint exchanging message directly.        
 
         [0015]     The present invention also provides a method for providing first endpoint and second endpoint with authentication information in a communication system.  
         [0016]     According to one aspect, the method for providing first endpoint and second endpoint with authentication information in a communication system includes: 
        sending, by the first endpoint, an access request (ARQ) message containing first key parameter of the first endpoint to first GK where the first endpoint locates;     upon receiving the ARQ message, sending, by the first GK, a location request (LRQ) message containing the first key parameter to second GK where the second endpoint locates;     upon receiving the LRQ message, sending, by the second GK, an information request (IRQ) message containing the key first parameter to the second endpoint;     upon receiving the LRQ message, the second endpoint getting the first key parameter and generating second key parameter of the second endpoint based on the first key parameter;     the second endpoint generating a share key based on the first key parameter and the second key parameter;     sending, by the second endpoint, an information response request (IRR) message containing the second key parameter to the second GK;     upon receiving the IRR message, sending, by the second GK, an location confirm (LCF) message containing the second key parameter to the first GK;     upon receiving the LCF message, sending, by the first GK, an access confirm (ACF) message containing the second key parameter to the first endpoint;     upon receiving the ACF message, the first endpoint getting the second key parameter and generating the share key based on the first key parameter and the second key parameter.        
 
         [0026]     According to another aspect, the method for providing first endpoint and second endpoint with authentication information in a communication system includes: 
        ending, by the first endpoint, an access request (ARQ) message containing first key parameter of the first endpoint to a GK where the first endpoint and second endpoint locate;     upon receiving the ARQ message, sending, by the GK, an information request (IRQ) message containing the first key parameter to the second endpoint;     upon receiving the LRQ message, the second endpoint getting the first key parameter and generating second key parameter based on the first key parameter;     the second endpoint generating a share key based on the first key parameter and the second key parameter;     sending, by the second endpoint, an information response request (IRR) message containing the second key parameter to the GK;     upon receiving the IRR message, sending, by the GK, an access confirm (ACF) message containing the second key parameter to the first endpoint;     upon receiving the ACF message, the first endpoint getting the second parameter and generating the share key based on the first key parameter and the second key parameter.        
 
         [0034]     Seen from the description of above mentioned technical scheme provided by the present invention, it is obvious that the authentication information for direct message transmission between different endpoints needs to be confirmed through negotiation, and the authentication information needs to be negotiated through GK in a secure manner so as to guarantee security of negotiated authentication information between different endpoints. Since a GK can perform security authentication to endpoints dominated by the GK, endpoints can also perform security authentication to their home GKs, and different GKs perform mutual authentication to each other. Because the security of RAS messages can be guaranteed, the security of negotiated authentication information can be guaranteed through secure RAS message. The authentication information of the present invention adopts Diffie-Hellman key exchange technology, which needs not to encrypt and decrypt the intermediate key information such as ClearToken, thereby having no special demands for the intermediate entities such as GK in H.323 system and applying no effect to the performance of intermediate entities. When RAS messages are used to negotiate the shared key, there is no need to statically precontract shared key between different endpoints, which not only permits direct secure message transmission between different endpoints, but also increases the scalability of the H.323 network which is poor by using symmetrical key system in H.235 protocol before. Therefore, the present invention designates and provides a secure framework of message transmission in H.323 system in direct routing mode, thereby improving the security of H.323 system. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0035]      FIG. 1  is a schematic flow illustrating message transmission in a H.323 system in accordance with a preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0036]     The present invention will be described in detail hereinafter with reference to accompanying drawings.  
         [0037]     According to a preferred embodiment of the present invention, authentication required information for direct message transmission between different endpoints is confirmed through GK routing, and then different endpoints exchange messages directly based on the negotiated authentication required information.  
         [0038]     In this way, the present invention puts forward how to negotiate the authentication information for direct message transmission between different endpoints through message transmission of GK-routed model.  
         [0039]     Since H.235 protocol of ITU-T provides secure frameworks for message transmission of GK-routed model in H.323 systems, negotiating the authentication information between different endpoints through message transmission of GK-routed model in the present invention can guarantee the security of negotiating the authentication information.  
         [0040]     In the present invention, H.225 protocol RAS message transmission is adopted to negotiate the authentication information for direct message transmission between different endpoints. In order to guarantee the security of negotiated authentication information, the security of RAS message should be guaranteed, so the technical scheme provided by the present invention should be implemented under the condition that the security of RAS message is guaranteed.  
         [0041]     Since the RAS message should be transmitted through such network entities as endpoint and GK, in order to guarantee the security of RAS message, the GK should perform security authentication to its dominated endpoints, and these endpoints should perform security authentication to their home GK respectively, leading to the endpoints and their home GK trust in each other. Authentication should be implemented between different GKs to avoid malicious network attacks. Through above authentications, secure transmission of RAS message between different endpoints dominated by the same home GK and different GKs can both be guaranteed.  
         [0042]     Direct message transmission between different endpoints includes Q.931 message transmission. Shared key is involved in authentication between different endpoints. Since the key exchange technology based on Diffie-Hellman needs no encryption during the procedure of negotiating shared key between an endpoint of one participator and an endpoint of the other participator, it is adopted in the present invention to negotiate the shared key between different endpoints. In this way, there is no need to encrypt information during the procedure of negotiating the shared key, so the performance of the middle entities such as GK in H.323 systems may not be affected by the negotiating process of the shared key.  
         [0043]     In this embodiment, different endpoints are set as Endpoint  1  and Endpoint  2 , which adopt direct-routed model, rather than GK-routed model, to implement secure message transmission. In the present embodiment, the steps of determining authentication information for direct message transmission between Endpoint  1  and Endpoint  2  include: firstly, Endpoint  1  transmits its key parameters to Endpoint  2  through GK-routed model, and then Endpoint  2  generates its own key parameters according to the key parameters of Endpoint  1  and transmits its own key parameters to Endpoint  1  through GK-routed model. In this way, a shared key between Endpoint  1  and Endpoint  2  is generated, and when using this shared key, the security of direct-routed Q.931 message transmission between Endpoint  1  and Endpoint  2  can be guaranteed.  
         [0044]     The detailed technical scheme of determining the authentication information during direct message transmission between Endpoint  1  and Endpoint  2  provided in this embodiment includes: set home GK of Endpoint  1  as GK 1 , and Endpoint  1  can load its key parameters in a parameter dhkey of ClearToken, designate in a ClearToken that the ClearToken is transmitted by Endpoint  1  and will be transmitted to Endpoint  2 , and then load the ClearToken in a RAS message, say an access request (ARQ) message, where the called address in the ARQ message is the address of Endpoint  2 . Endpoint  1  transmits the ARQ message to GK 1 .  
         [0045]     Upon receiving the ARQ message transmitted from Endpoint  1 , GK 1  decides whether GK 1  is the home GK of Endpoint  2  according to the called address in the ARQ message. If GK 1  is the home GK of Endpoint  2 , i.e., Endpoint  1  and Endpoint  2  belongs to the same GK, GK 1  will load the ClearToken contained in the ARQ message in an information request (IRQ) message and transmit the IRQ message to Endpoint  2 . If GK 1  is not the home GK of Endpoint  2 , GK 1  should inquire the address of Endpoint  2  through other GKs connected with it. If a GK, say GK 2 , is connected with GK 1 , GK 1  carries the ClearToken contained in the ARQ message in a location request (LRQ) message and transmits the LRQ message to GK 2 .  
         [0046]     Upon receiving the LRQ message, GK 2  can determine that the ClearToken information needs to be transmitted to Endpoint  2  according to the ClearToken contained in the LRQ message. GK 2  decides whether it is the home GK of Endpoint  2  according to the called address in the LRQ message, if so, GK 2  will load the ClearToken in an information request (IRQ) message and transmit the IRQ message to Endpoint  2  in time; otherwise, GK 2  should go on to inquire the address of Endpoint  2  to other GKs connected with it.  
         [0047]     Upon receiving the IRQ message transmitted from GK 2 , Endpoint  2  obtains the key parameters of Endpoint  1  from the dhkey of ClearToken in the IRQ message, generates key parameters of Endpoint  2 , computes a session key by Diffie-Hellman algorithm, and then carries the key parameters of Endpoint  2  in dhkey of ClearToken in an information request response (IRR) message. It needs to designate in the ClearToken that the ClearToken is transmitted by Endpoint  2  and will be transmitted to Endpoint  1 . Then Endpoint  2  transmits the IRR message to its home GK, GK 2 .  
         [0048]     Upon receiving the IRR message, GK 2  determines that the ClearToken will be transmitted to Endpoint  1  according to the ClearToken, i.e., GK 2  determines the endpoint which should be responded in the IRR message is Endpoint  1 . Then GK 2  decides whether it is the home GK of Endpoint  1 , if so, Endpoint  1  and Endpoint  2  belong to the same GK, GK 2 , and GK 2  should load the ClearToken of the IRR message in an access confirm (ACF) message and transmit the ACF message to Endpoint  1 . If the GK 2  is not the home GK of Endpoint  1 , Endpoint  1  and Endpoint  2  belong to different GKs, Endpoint  1  belonging to GK 1  and Endpoint  2  belonging to GK 2 . Since a location confirm (LCF) message corresponds to the LRQ message, GK 2  should load the ClearToken of the IRR message in the LCF message and transmit the LCF message to GK 1 . Upon receiving the LCF message from GK 2 , GK 1  determines that the ClearToken needs to be transmitted to Endpoint  1  according to the ClearToken in the LCF message, and carries the ClearToken in an ACF message and transmits the ACF message to Endpoint  1 . Endpoint  1  obtains the key parameters of Endpoint  2  from the ClearToken contained in the ACF message. In this way, A shared key between Endpoint  1  and Endpoint  2  is generated and can be used for direct-routed message transmission.  
         [0049]     Since H.235 protocol permits various kinds of message authentication to be carried in H.323 message, the technical scheme provided in the present invention is applicable to GK-routed model without any modification, i.e., the endpoints belonging to the same home GK or different home GKs obtain a shared key using the above method, and implement message transmission using the shared key through GK-routed model.  
         [0050]     Now, the technical scheme of the present invention will be described in detail hereinafter with reference to  FIG. 1 .  
         [0051]     In  FIG. 1 , the dashed lines indicate the H.225 protocol based RAS message transmission, and the solid lines indicate the H.235 protocol based Q.931 message transmission. EP 1  and EP 2  indicate two different endpoints in a H.323 system, and GK 1  and GK 2  indicate two different GKs in the H.323 system. GK 1  is home GK of EP 1 , and GK 2  is home GK of EP 2 .  
         [0052]     In this embodiment of the present invention, GK discovery procedure (GRQ/GCF), endpoint registration procedure (RRQ/RCF) and security negotiation between endpoint and its home GK will not be described in detail. Please refer to H.235 protocol for the detailed description.  
         [0053]     Step 1: EP 1  carries the desired shared key parameters in ClearToken of an ARQ message, sets the generalID in the ClearToken as EP 2 , and sets the sendersID in the ClearToken as EP 1 . In this way, it can be defined that the ClearToken is transmitted from EP 1  to EP 2 . EP 1  transmits the ARQ message to its home GK, GK 1 .  
         [0054]     Step 2: Upon receiving the ARQ message, GK 1  transforms the ARQ message to a LRQ message and inquires address of EP 2  to GK 2  since the called endpoint in the ARQ message is EP 2  which doesn&#39;t belong to GK 1 . When transforming the ARQ message, GK 1  knows that information in the ClearToken is to be transmitted to EP 2  according as the generalID in the ClearToken is EP 2 , so GK 1  carries all information in the ClearToken of the ARQ message in the LRQ message, and transmits the LRQ message to GK 2 .  
         [0055]     Step 3: Upon receiving the LRQ message transmitted from GK 1 , GK 2  determines the generalID of ClearToken in the LRQ message is EP 2 , indicating that GK 2  need to transmit the ClearToken information to EP 2 . Since GK 2  is the home GK of EP 2 , GK 2  carries the ClearToken in an IRQ message and then transmits the IRQ message to EP 2 , thereby transmitting the ClearToken to EP 2  in time.  
         [0056]     Step 4: Upon receiving the IRQ message transmitted from GK 2 , EP 2  extracts the dhkey parameter of EP 1  from the ClearToken of the IRQ message, generates Diffie-Hellman parameter of its own, computes a session key using Diffie-Hellman algorithm, and then sets its own Diffie-Hellman parameter to the dhkey parameter in ClearToken of an IRR message. At last, sets generalID in the ClearToken as EP 1 , and sets sendersID in the ClearToken as EP 2 , indicating that the ClearToken is transmitted from EP 2  to EP 1 . After that, EP 2  transmits an IRR message to GK 2 .  
         [0057]     Step 5: Upon receiving the IRR message transmitted from EP 2 , GK 2  determines that the ClearToken needs to be transmitted to EP 1  according to the generalID contained in the ClearToken of the IRR message. GK 2  should load the ClearToken in a message and transmits the message to EP 1 . GK 2  may load the ClearToken in a LCF message which corresponds to the LRQ message in Step 2, and transmit the LCF message to GK 1 .  
         [0058]     Step 6: Upon receiving the LCF message transmitted from GK 2 , GK 1  extracts the ClearToken information contained in the LCF message and knows that the ClearToken should be transmitted to EP 1  according to generalID in the ClearToken, so GK 1  carries the ClearToken information in an ACF message and transmits the ACF message to EP 1 .  
         [0059]     Upon receiving the ACF message transmitted from GK 1 , EP 1  obtains Diffie-Hellman parameters of EP 2  from the ClearToken of the ACF message, and then computes a session key using Diffie-Hellman algorithm. In this way, a shared key between EP 1  and EP 2  is generated through Diffie-Hellman key exchange, and the shared key is expressed as ShareddKeyEp 1 Ep 2 . After the shared key between EP 1  and EP 2  is generated, the security of direct message transmission between EP 1  and EP 2  can be guaranteed.  
         [0060]     The method for applying key during direct message transmission between EP 1  and EP 2  is the same as the specification of H.235 protocol, which will be illustrated as Step 7 to Step 10:  
         [0061]     Step 7: EP 1  encrypts a call setup request (Setup) message using ShareddKeyEp 1 Ep 2  and then directly transmits the Setup message to EP 2 .  
         [0062]     Step 8: Upon receiving the Setup message directly transmitted from EP 1 , EP 2  performs authentication to the transmitting party of the Setup message, EP 1 , using ShareddKeyEp 1 Ep 2 , and if authentication is successful, EP 2  encrypts an Altering message using ShareddKeyEp 1 Ep 2 , and directly transmits the encrypted Altering message to EP 1 .  
         [0063]     Step 9: EP 2  encrypts a call connection message using ShareddKeyEp 1 Ep 2  and directly transmits the encrypted call connection message to EP 1 .  
         [0064]     Step 10: When any party of EP 1  and EP 2  desires to release the call connection, the initiating party of release will encrypt a call release message using ShareddKeyEp 1 Ep 2  and directly transmit the encrypted call release message to the other party. For example, EP 1  desires to release the call connection, and then EP 1  encrypts the call release message using ShareddKeyEp 1 Ep 2  and directly transmits the encrypted call release message to EP 2 .  
         [0065]     Step 1 to Step 10 in the embodiment describe a method for securing direct message transmission between two endpoints which belong to different GKs. The method is also adopted to secure direct message transmission between two endpoints which belong to the same GK, and under this condition, since EP 1  and EP 2  belong to the same GK, i.e., GK 1  and GK 2  is the same GK, Step 2 and Step 5 can be skipped, with other steps reserved, which will not be illustrated in detail.  
         [0066]     To sum up, what is said above is just a relatively preferred embodiment of the present invention. It is not intended to limit the protection scope of the present invention.