A method of carrying out an authentication check between a base station and a mobile station in a mobile radio system.

A method for carrying out authentication testing between a fixed station and a mobile station in a mobile broadcasting system

Description I full

Background of the invention

The present invention relates to a method for carrying out an authentication test process between a fixed station and a mobile station in a mobile broadcasting system, in particular a mobile cellular telephone system. The proposed method can also be applied to mobile phone systems. Others, such as automated pager systems, for example.

In the case of a mobile cellular telephone system, for example, an authentication test process is performed before any communication is established between the mobile station and the fixed station. The fixed station requests information about the mobile station in terms of its identity by asking the mobile station to send its identity number, and thus the mobile station is forced to reveal its identity to the fixed station so that the latter (the fixed station) knows which mobile station bears the costs of the call that followed the request. .

On the other hand, the mobile station must ensure that it is in contact with the correct authorized fixed station, i.e. with a genuine fixed station that is genuinely approved for communication line connection when the mobile station is the calling party (since the mobile station is Subscriber A) and - i.e. the mobile station - She will clearly bear the costs of the call.

In order to perform the authentication test, it must be preceded by knowledge of the formation and composition of the authentication signals, that is, the “response” signals at the fixed station. A random number (RAND) is sent from the fixed station to the mobile stations located within the area covered by the fixed station, and the mobile station responds with a known signal. Given (Response 1) In a similar manner, the fixed station forms the same response (Response 1) from the random number and the identity of the mobile station calling. These signals usually match, and the fixed station instructs the mobile station to enter a communication channel.

General description of the invention

Thus, in the previously known method of carrying out authentication tests, a pair of RAND-Resonse signals is formed for a given mobile station, that is, a given response signal is generated in the mobile station for a received random call number, and thus a fixed station can receive a number of such response signals. For any number of different random call numbers, this means that it is possible to create a fixed 'false' station capable of transmitting a number of different random numbers alternately, and receiving a correspondingly different number of answer signals. Thus, the false fixed station can create a shared mobile station that is not authorized to send calls through the system. This shortcoming or deficiency in the known authentication test is due to the fact that the test is one-way, meaning that only the fixed station requires the response signal as proof of the mobile station’s documentation and approval.

According to the current method, the authentication test has been made two-way, meaning that it is not only the fixed station that requires knowledge of the identity of the mobile station, but rather the mobile station also requires knowledge of the identity of the fixed station.

The purpose of this current invention is to find an improved test method to ensure authentication, so that it is impossible for a false fixed station to enter with the intention of trying to find out the approved and authenticated code of the mobile telephone system.

The method of this present invention is described in the steps stated in the paragraph highlighting the claim element (1). Further developments and steps of the proposed method are announced in the following two protection elements (2-3).

Brief explanation of the drawings

Now this invention will be described in more detail through the attached drawings

It contains:

Figure (1) shows a regular connection plan between two fixed stations and a group of stations

Mobile.

Figure (2) shows a tabular map of a form of the proposed method.

Figure (3) shows a diagram of the total amounts of inputs and outputs in a documentation accounting system integrated into a mobile station, while Figure (4) is a tabular map showing another form of the proposed method.

Detailed description

Figure (1) shows a reliable fixed station (MS1-MSn) listening by sending random numbers to a group of mobile stations over a given control channel. Among these mobile stations, a response signal is received from the mobile station MSk indicating that it wishes to issue a call over a given control channel. Given an address, as described above, a one-way authentication test is performed where the fixed station requires a response from the MSk. This process will be described in more detail below with reference to Figure (2). Since communication is unidirectional during this stage, a false base station (BSF) is able to obtain a response from a number of mobile stations when it sends the aforementioned random number (RAND) in the aforementioned manner. Thus, the false base station (BSF) can create The set of random responses can then be exploited by a mobile station illegally.

In order to prevent this from happening and in line with the merits of this invention, there is a proposed method for documenting the test shown in the graphic map of the sequence of stages in Figure (2).

A reliable fixed station listens to a number of mobile stations (MS1-MSn) within the area covered by the said fixed station during a random number (RAND) transmission in the sequential phase (1). A certain MSk that wishes to issue a call responds by emitting a response signal (1) as indicated by the relay phase (2). This signal in the precise operating device in the mobile station consists of several input data (PIN), (ESN), and (DN), in addition to the received random number (RAND) [Figure (3)], where the symbol (PIN) represents the personal identification number of the mobile station. The symbol (ESN) represents the electronic serial number, and the symbol (DN) represents the managed number (the number to be called). Thus, the mobile station (MSk) becomes one of the subscribers (A), and then a device is issued

Operation 13 Response signal (1) consisting of an 18 binary digit authenticated signal and an 8 binary digit random signal sent to the fixed base station.

The fixed station performs a calculation of the response signal (1) in a manner similar to the views of the sequential stage (3) of the entering authenticated signals and random signals, and it is compared with the value of the response signal calculated and sent by the mobile station, the sequential stage (4). When the values match, the fixed base station allows the station to enter. The mobile phone is transferred to a communication channel with a specific location, sequential stage (5), and communication is carried out in a known way, sequential stage (6). This method described previously is known before.

According to the proposed method, the fixed station gives a response signal (response 2) consisting of another random number (random 2) and the personal identification number (PIN) to the mobile station, and this last number is known to the fixed base station (sequential stages 2 and 3) and sends both The two signals (response 2 and random 2) are sent to the mobile station, sequential stage (7). The mobile station then estimates the signal value (response 2) through the personal identification number (PIN).

The receiving random number (random 2), the sequential stage (8). A comparison is now made in the mobile station, sequential stage (9), between the received response signal (response 2) and the value composing the response signal (2). If these two values agree and match, the mobile station forms a third response value (response 3) and sends this value to the station. Fixed, sequential phase (10). The signal [response (3)] consists of the random signal (random 2) and the personal identification number (PIN) of the mobile station. The fixed station forms the third response (response 3) in a similar way from the two numbers [random (2)] and (PIN) known at the fixed station (sequential stage (1)). A comparison is made [sequential stage (12)] between the two received values that make up the third response (response 3). If the two values agree and match, communication continues and communication takes place.

The steps of the method according to the sequential stages (7), (8) and (9) provide a documentary test by which the mobile station decides whether the base station is reliable or unreliable, as verification of the second response signal (response 2) sent from the base station is done. At the mobile station, it was done

Also compare it with the second response value (response 2) calculated at the aforementioned mobile station. Therefore, the second response signal (Response 2) from the base station can be considered as a response signal from the mentioned station. The aforementioned method constitutes the main difference between the proposed method and the known method according to the sequential stages (2), (3) and (4).

The testing carried out according to sequential stages (10), (11) and (12) essentially replicates the method carried out according to sequential stages (2), (3) and (4), i.e. a test carried out from the base station verifies that the mobile station is reliable.

There is a fundamental difference related to the known documentation method (according to sequential stages 1-4).

The only thing that the mobile station also requires is a second response (response 2) from the base station, and this response is verified according to the sequential stages (7-9). So the false base station must know exactly how to calculate this response signal, so this test is a two-way test.

The authentication test according to the sequential stages (2), (3) and (4) can be carried out on a common control channel in the mobile broadcasting system, and the authentication test according to the sequential stages (7 - 12) can be carried out on the communication channel established between the fixed base station and the mobile station. (MSK) (sequential stages (5) and (6)).

Figure (4) represents a diagram of the sequence of stages showing the steps of the first method in the case of implementing the two-way authentication test alone. In this case, the steps according to the sequential stages (1-3) replace the steps according to the sequential stages (1-6). Shown in Figure (2). In this case also, no known one-way authentication test is performed before performing a two-way test. For example, a calling station such as MSK requests a call from the fixed base station. When the connection is made and the base station receives that call, it searches for a vacant speech channel and asks the mobile station (MSK) to enter that vacant channel. In this way, a pure communication takes place over the speech channel without the need to conduct an authentication test, and then

The actual documentation test is conducted in the previously mentioned manner with reference to the sequential stages (7 12) of Figure (2), meaning that only a two-way documentation test is conducted.