Title of Invention

METHOD AND ARRANGEMENT FOR CHECKING THE AUTHENTICITY OF A FIRST COMMUNICATION SUBSCRIBER IN A COMMUNICATIONS NETWORK

Abstract

The invention relates to a method for checking the authenticity of a first communication subscriber (203, 204) in a communications network having the first communication subscriber and having a second communication subscriber (201), in which a first fault detection data item is formed at the first communication subscriber, in which at the second communication subscriber a fault information item is formed using a formed second fault detection data item of the second communication subscriber and an information item relating to a random data item which was transmitted from the first communication subscriber to the second communication subscriber said fault information item including the second fault detection data item of the second communication subscriber and the information item relating to the random data item in which the fault information item is transmitted from the second communication subscriber to the first communication subscriber in which at the first communication subscriber the second fault detection data item of the second communication subscriber and the first fault detection data item of the first communication subscriber are checked using the fault information item.

Full Text

The invention relates to a method and an arrangement for checking the authenticity of a first communication subscriber in a communication network. In a communications network* data is generally transmitted between communication subscribers for example a service provider and a service user. In order to protect a communications network against penetration of an unauthorised communication subscriber into the communications network the authenticity of each communication subscriber is generally checked. Document [1] discloses a method and an arrangement for checking the authenticity of a communication subscriber in particular of a service provider or of a service user in a communication network. the method known from document [l] and the corresponding arrangement are based on what is referred to as 36 T8 33.102 Version 3.0.0 Draft Standard, which describes a security architecture of a mobile phone system. In Fig. 4, the procedure during the checking of the authenticity of a communication subscriber cuch as is known from the document [1] in illustrated symbolically and parts thereof will be explained below briefly. A transmission of data 10 illustrated in Fig. 4 by an arrow in each case. A direction of an arrow characterizes a transmission direction during a data transmission. Fig. 4 shows a mobile phone system 400, comprising a user 401 of a communication service, for example a mobile phone, and a provider 402 of a communication service. The provider 402 comprises a dial-in network 403 with a dial-in network operator from which the user 401 locally requests a communication service, and a home network 404 with a home network operator with which the user 401 is signed on and registered. In addition, the user 401, the dial-in network 403 and the home network 404 each have a central processing unit with a memory, for example a server (central computing unit), with which processing unit the procedure described below is monitored and controlled and on which memory data is stored. The dial-in network 403 and the home network 404 are connected to one another via a data line over which digital data can be transmitted. The user 401 and the dial-in network 403 are connected to one another via any desired transmission medium for the transmission of digital data. During a communication, the user 401 dials 410 into the dial-in network 403. At the start of the communication, checking of both the authenticity of the user 401 and the authenticity of the provider 402 is carried out. To do this, the dial-in network 403 requests 411 what is referred to as authentication data from the home network 404, with which data the authenticity of the user 401 and of the provider 402 can be checked. The authentication data which is obtained from the home network 404 comprises a random number and a sequential number of the provider 402. The sequential number of the provider 402 is obtained in such a way that a counter of the provider 402 increases the sequential number of the provider 402 by the value 1 at each attempt at communication between the user 461 and the provider 402. It is to be noted that the random number and the sequential number of the provider 402 only constitute part of the authentication data and are not to be understood as comprehensive. Further authentication data is known from [1]. The home network 404 transmits 412 the requested authentication data to the dial-in network 403. The dial-in network 403 processes the received authentication data in a suitable way 413, and transmits 414 the processed authentication data to the user 401. The user 401 checks 415 the authenticity of the provider 402 using a dedicated sequential number, which is handled in a way corresponding to the sequential number of the provider 402, and using the sequential number of the provider 402. The procedure during the checking of the authenticity of the provider 402 is described in [1]. A result of the checking of the authenticity of provider 402, "authenticity of provider satisfactory" 416, "authenticity of provider satisfactory but sequential fault has occurred" 417 or "authenticity of provider not satisfactory" 418, is transmitted 419 from the user 401 to the provider 402. In the case of the result "authenticity of provider satisfactory" 416, the dial-in network 403 checks 420 the authenticity of the user 401 as described in [1]. In the case of the result "authenticity of provider not satisfactory" 418, the communication is interrupted and/or restarted 421. In the case of the result "authenticity of provider satisfactory but a sequential fault has occurred" 417, resynchronization takes place in such a way that the home network 404 transmits 422 a resynchronization request to the user 401. The user responds with a resynchronization response in which resynchronization data is transmitted 423 to the home network 404. The sequential number of the provider 402 is changed 424 as a function of the resynchronization response. The authenticity of the user 401 is then checked, as is known from [1]. The procedure described has the disadvantage that during checking of the authenticity of a communication subscriber, in particular during the checking of the authenticity of a service provider, a large amount of data has to be transmitted between the communication subscribers. The invention is thus based on the problem of disclosing a method which is simplified and improved in comparison with the known method and the known arrangement, and a simplified and improved arrangement for checking the authenticity communication. subscriber in a communications network. The problem is solved by means of the methods and by means of the arrangements having the features in (accordance with the independent patent claims. In the method for checking the authenticity of a first communication subscriber in a communications network, a first fault information item is formed in the first communication subscriber using a fault detection data item of the first communication subscriber and an information item relating to a random data item. In a second communication subscriber in the communications network, a second fault information item is formed using a fault detection data item of the first communication subscriber and the information relating to the random data item. The authenticity of the first communication subscriber is checked using the first fault information item and the second fault information item. In the arrangement for checking the authenticity of a first communication subscriber in a communications network, the first communication subscriber is set up in such a way that a first fault information item can be formed using a fault detection data item of the first communication subscriber and an information item relating to a random data item. In addition, the arrangement has a second communication subscriber in the communications network which is set up in such a way that a second fault information item can be formed using a fault detection data item Of the second communication subscriber and the information relating to the random data item. The authenticity of the first communication subscriber can be checked using the first fault information item and the second fault information item. The checking of the authenticity of a communication subscriber in a communications network is to be understood as meaning method steps which are carried out in the wider sense with checking of the authorization of a communication subscriber for access to a communications network or participation in communication in a communications network. This thus encompasses both method steps which are carried out within the scope of the checking of the authorization of a communication subscriber for access to a communications network and such method steps which are carried out within the scope of the processing or the administration of data which is used in the checking. Preferred developments of the invention are given in the dependent claims. The developments described below relate to the method and to the arrangement. The invention and the development described below can be implemented either using software or hardware, for example using a specific electrical circuit. In one refinement, the first communication subscriber is a service provider and/or the second communication subscriber is a service user in the communications network. A sequential number is preferably used as the fault detection data item. In one refinement, the information relating to the random data item is a random number. In one development, the checking of the authenticity is simplified by determining a difference between the fault detection data item of the first communication subscriber and the fault detection data item of the second communication subscriber. In one refinement, the checking of the authenticity is further improved with respect to the security of the communications network by limiting the difference. One development is preferably used within the scope of a mobile phone system. In the mobile phone system, the service user is implemented as a mobile phone and/or the service provider is implemented as a mobile phone network operator. An exemplary embodiment of the invention which is explained in more detail below is illustrated in the figures, in which figures: Figure 1 shows a mobile phone system; Figure 2 shows an outline in which checking of the authenticity of a communication subscriber is illustrated symbolically; Figure 3 shows a flowchart in which individual method steps are illustrated during checking of the authenticity of a service provider in a communications network; Figure 4 shows an outline in which checking of the authenticity of a communication subscriber in accordance with the 3G TS 33.102 Version 3.0.0 Standard is illustrated symbolically. Exemplary embodiment: mobile phone system A mobile phone system 100 is illustrated in Fig. 1. The mobile phone systerr 100, comprises e mobile phone 101, a local dial-in network 102 with a dial-in network operator 103 and a home network 104 with a home network operator 105. The mobile phone 101 is signed on and registered in the home network 104. In addition, the mobile phone 101, the dial-in network 102 and the home network 104 each have a central processing unit 106, 107, 108 with a memory 109, 110, 111, with which processing units 106, 107, 108 the procedure described below is monitored and controlled, and on which memories 109, 110, 111 data is stored. The dial-in network 102 and the home network 104 are connected to one another via a data line 112 via which digital data can be transmitted. The mobile phone 101 and the dial-in network 102 are connected to one another via any desired transmission medium 113 for transmitting digital data. The procedure during the checking of the authenticity of the mobile phone 101 and the procedure during the checking of the authenticity of the home network 104 and/or of the home network operator 105 are illustrated symbolically in Fig. 2, and parts thereof will be explained below briefly. The transmission of data in Fig. 2 is illustrated in each case by an arrow. A direction of an arrow characterizes a transmission direction during a data transmission. The procedure which is described below and illustrated symbolically in Fig. 2 is based on what is referred to aa a 30 TS 33.102 Version 3.0.0 Standard, which describes a security architecture of a mobile phone system and is described in [1] . During a communication, the mobile phone 201 dials 210 into the dial-in network 203. At the start of the communication, checking both of the authenticity of the mobile phone 201 and of the authenticity of the home network 204 and/or of the home network operator takes place. To do this, the dial-in network 203 requests 211 authentication data from the home network 204, with which authentication data the authenticity of the user 201 and of the home network 204 and/or of The home network operator can be checked. The authentication data which is determined by the home network 204 comprises a random number and a sequential number of the home network 204 (cf. Fig. 3 step 310). The sequential number of the home network 204 is determined in such a way that a counter of the home network 204 increases the sequential number of the home network 204 by the value 1 at each attempt at communication between the mobile phone 201 and the home network 204. It is to be noted that the random number and the sequential number of the home network 204 only constitute part of the authentication data and are not to be understood as comprehensive. Further authentication data is specified in [1]. The home network 204 transmits 212 the requested authentication data to the dial-in network 203. The dial-in network 203 processes the received authentication data in a suitable way 213 and transmits 214 the processed authentication data to the mobile phone 201. The mobile phone 201 checks 215 the authenticity of the home network 204 using a dedicated sequential number" which is handled in a way corresponding to the sequential number of the home network 204, and using the sequential number of the home network 204. In a way corresponding to the home network 204, the mobile phone 201 also has a counter. The procedure during the checkinq of the authenticity of the home network 204 is described in [l] . Method steps which differ" therefrom are described below. What is referred to as overflow checking of the counter of the mobile phone 201 is carried out within the scope of the checking of the authenticity of the home network 203. This overflow checking prevents overflowing of an acceptable numerical range of the counter of the mobile phone 201. In the overflow checking, the following conditions are tested: 1) sequential number of the home network 204 > sequential number of the mobile phone 201; 2) sequential number of the home network 204 sequential number of the mobile phone 201 predefinable deviation (1,000,000); the following applying for the predefined deviation: predefinable deviation is sufficiently large in order to ensure, during normal or fault-free communications operation: that the sequential number of the home network 204 - sequential number of the mobile phone 201 is not > predefinable deviation; the maximum permissable sequential number of the mobile phone 201/predefinable deviation is sufficiently large in order to ensure the" the maximum permissible- sequential number of the mobile,, phone 201 is not reached during operation. The result of the checking of the authenticity of the home network 204, "authenticity satisfactory" 216, "authenticity satisfactory but a sequential fault has occurred" 217 or "authenticity not satisfactory" 218 is transmitted 419 to the home network 204 from the mobile phone 201. In the case of the result "authenticity satisfactory" 216, the dial-in network 203 checks 220 the authenticity of the mobile phone 201, as described in [1]. In the case of the result "authenticity not satisfactory" 218, the communication is interrupted or restarted 221 In the case of the result "authenticity satisfactory but a sequential fault has occurred" 217, resynchronization 222 takes place. Resynchronization is to be understood as a change of the sequential number of the home network 204. For this purpose, the mobile phone 201 transmits 222 resynchronization data to the dial-in network 203. The resynchronization data comprises the same random number which was transmitted within the scope of the authentication data, and the sequential number of the mobile phone 201 (cf. Fig. 3 step 320). The dial-in network 203 processes the resynchronization data in a suitable way and transmits the processed resynchronization data to the home network 204. The home network checks the sequential number of the mobile phone 201 and the sequential number of the home network 204 using the processed resynchronization data, and if appropriate changes 223 the sequential number of the home network 204 (cf. Fig. 3 step 330). The home network 204 subsequently transmits new authentication data, which if appropriate comprises the changed sequential number of the home network 204, to the dial-in network 203. In order to illustrate the described procedure, important steps 300 of the procedure are illustrated in Fig. 3. Fig. 3 shows a first step 310 within the scope of which the authentication data (first fault information) is determined. The resynchronization data (second fault information) is determined within the scope of a second step 320. The sequential number of the mobile phone and the sequential number of the home network are checked within the scope of a third step 330, using the resynchronization data. An alternative of the first exemplary embodiment is described below. In the alternative exemplary embodiment, a method is implemented in which the home network is made more reliable with respect to a data loss in the event of a system crash. For this purpose, the current sequential number of the home network is stored in the memory of the home network, in each case at a predef inable time interval. A sequential number of the home network which has been lost during a system crash of the home network is restored in such a way that a predefinable additional value is added to the value of the stored sequential number. The predefinable additional value is 'dimensioned in such a way that exceeding of the sum of the sequential number of the mobile phone and the predefinabie deviation is not exceeded. In the alternative exemplary embodiment, the predefinable additional value is determined in such a way that an average number of authentication attempts on one' "day by the home network, which number is determined during operation of the communications network, is multiplied by a factor with the value 10. The following publication is cited in this document: [1] 3G TS 33.102 Version 3.0.0 Draft Standard, 3rd Generation Partnership Project, Technical Specification Group Services and System Aspects, 3G Security, Security Architecture, 05/1999. WE CLAIM 1. Method for checking the authenticity of « first communication subscriber (203, 204) in a communications network having the first communication subscriber and having a second communication subscriber (201), in which a first fault detection data item is formed at the first communication subscriber, - in which at the second communication subscriber a fault information item is formed using a formed second fault detection data item of the second communication subscriber and an information item relating to a random data item which was transmitted from the first communication subscriber to the second communication subscriber said fault information item including the second fault detection data item of the second communication subscriber and the information item relating to the random data item in which the fault information item is transmitted from the second communication subscriber to the first communication subscriber - in which at the first communication subscriber* th« second fault detection data item of the second communication subscriber and the first fault detection data item of the first communication subscriber are checked using the fault information item. 2. Method as claimed in claim 1, - in which authentication data which includes the first fault detection data item of the first communication subscriber and the information relating to the random data item is transmitted from the first communication subscriber to the second communication subscriber. 3. Method as claimed in claim 1 or 2, in which at the second communication subscriber the authenticity of the first communication sub- scriber is checked wherein it is checked whether the first fault detection data item lies in a pre— definable range. 4. Method a claimed in claim 3, - in which the checking a» to whether the restored first fault detection data item lies in the pre- definable range is carried out in such a way that a difference between the two fault detection data items is formed - that a sequence error is formed if the difference does not lie in the predefinable range. 3. Method as claimed in claim 4, - in which a sequence error information item is formed if the difference does not lie in the pre- definable range. - in which the sequence error information item contains the information relating to the random number and the second fault detection data item* - in which the sequence error information item is transmitted from the second communication sub- scriber to the first communication subscriber. 6. Method as claimed in claim 5, - in which the sequence error information item is verified at the first communication subscriber, 9 - and in which a value of the first fault detection data item is changed at the first communication subscriber as a function of a value of the second fault detection data item. 7. Method as claimed in claim 6, - in which the verification and the changing are carried out at the first communication subscriber, 8. Method as claimed in claim 6 or 7, - in which authentication data which is adapted using the changed first fault detection data item of the first communication subscriber and the information relating to the random data item is determined. 9. Method as claimed in one of the preceding - claims in which the first and/or second fault detection data item is/are (a) sequential number (5). 10. Method as claimed in one of the preceding claimst - in which the information relating to the random data item is a random number. 11. Method as claimed in one of the prececdiog claims, - in which the first communication subscriber is a a service provider and/or the second communication subscriber is/are a service user in the communications network. 12. Method as claimed in claim 9, in which the service provider is a mobile phone operator of a mobile phone system and/or the service user is/are a mobile phone. 13. Method as claimed in one of the preceding claims - used for resynchronization of the first and second fault detection data items wherein the first fault detection data item is changed. 14. Arrangement for checking the authenticity of a first communication subscriber (203, 204) in a communications network having the first communication subscriber and having a second communication subscriber (201). - in which the first communication subscriber is set up in such a may that a first fault detection data item is formed at the first communication subscriber, - in which the second communication subscriber is set up in such a way that at the second communi- cation subscriber a fault information item is formed using a formed, second fault detection data item of the second communication subscriber and an information item relating to a random data item which was transmitted from the first communication subscriber to the second communication subscriber said fault information item including the second fault detection data item of the second communicat- ion subscriber and the information item relating to the random data item - in which the fault information item is transmitted from the second communication subscriber to the first communication subscriber - in which the first communication subscriber is set up in such a way that at the first communication subscriber the second fault detection data item and the first fault detection data item are checked using the fault information item. The invention relates to a method for checking the authenticity of a first communication subscriber (203, 204) in a communications network having the first communication subscriber and having a second communication subscriber (201), in which a first fault detection data item is formed at the first communication subscriber, in which at the second communication subscriber a fault information item is formed using a formed second fault detection data item of the second communication subscriber and an information item relating to a random data item which was transmitted from the first communication subscriber to the second communication subscriber said fault information item including the second fault detection data item of the second communication subscriber and the information item relating to the random data item in which the fault information item is transmitted from the second communication subscriber to the first communication subscriber in which at the first communication subscriber the second fault detection data item of the second communication subscriber and the first fault detection data item of the first communication subscriber are checked using the fault information item.

Documents:

581-KOLNP-2005-(26-10-2012)-FORM-27.pdf

581-KOLNP-2005-CORRESPONDENCE.pdf

581-KOLNP-2005-FORM 27.pdf

581-KOLNP-2005-FORM-27.pdf

581-kolnp-2005-granted-abstract.pdf

581-kolnp-2005-granted-claims.pdf

581-kolnp-2005-granted-correspondence.pdf

581-kolnp-2005-granted-description (complete).pdf

581-kolnp-2005-granted-drawings.pdf

581-kolnp-2005-granted-examination report.pdf

581-kolnp-2005-granted-form 1.pdf

581-kolnp-2005-granted-form 18.pdf

581-kolnp-2005-granted-form 2.pdf

581-kolnp-2005-granted-form 3.pdf

581-kolnp-2005-granted-form 5.pdf

581-kolnp-2005-granted-gpa.pdf

581-kolnp-2005-granted-reply to examination report.pdf

581-kolnp-2005-granted-specification.pdf

581-kolnp-2005-granted-translated copy of priority document.pdf

581-KOLNP-2005-PA.pdf