WO2000070842A2

WO2000070842A2 - Method for the management of data by a security module and corresponding security module

Info

Publication number: WO2000070842A2
Application number: PCT/FR2000/001354
Authority: WO
Inventors: Frédéric MAYANCE
Original assignee: Schlumberger Systemes
Priority date: 1999-05-18
Filing date: 2000-05-18
Publication date: 2000-11-23
Also published as: WO2000070842A3; EP1192795A2; FR2793979B1; CN1143517C; FR2793979A1; CN1353905A

Abstract

The invention relates to a method for the management of data belonging to a user card that can be introduced into at least one terminal, by a security module. Said card is subjected to at least one authentication process by said security module. The invention is characterized in that the method comprises the following stages: the card is introduced into a terminal; each time the user card is authenticated, a logical channel is allocated to said terminal in the security module; contextual data relating to the authentication stage are stored in a storage location associated with the logical channel, said storage location being located in a memory of the security module; and the card is withdrawn from the terminal. The invention is particularly suitable for use in telephony.

Description

METHOD FOR MANAGING DATA BY A MODULE

SECURITY AND SECURITY MODULE

The present invention relates to a data management method, by a security module, of a user card capable of being inserted into at least one terminal, said card being subjected to at least one authentication by said security module. It also relates to a security module adapted for its implementation.

The invention finds a particularly advantageous application in the field of telephony.

In the field of telephony, there are terminal administration systems which include an administration server and security modules generally embedded in hubs connected to said terminals. A concentrator comprises a computer, several security modules and an electronic card with which said modules are connected. The terminals are called public telephones. A security module guarantees the validity of a user card inserted in a public telephone, in particular through authentication of said card. To this end, said card includes secret data making it possible to guarantee its validity. Public telephone administration systems as well as secret data are managed by telephone operators. The concentrator manages several security modules, generally around thirty. A security module manages only one public telephone. The electronic card is used to administer communication between the telephones and the administration server. Although this device allows management of a fleet of public telephones, it has the disadvantage of being cumbersome to administer. In addition, the device thus set up is costly for telephone operators. Also, a technical problem to be solved by the object of the present invention is to propose a data management method, by a security module, of a user card capable of being introduced into at least one terminal, said card being subject at least one authentication by said security module, as well as a security module, which would make it possible to easily manage a fleet of terminals, at low cost, and this by reducing the administration device for said terminals.

A solution to the technical problem posed is characterized, according to a first object of the present invention, in that said data management method comprises the steps according to which:

- the card is introduced into a terminal,

- we allocate, in the security module, a logical channel to said terminal, - each authentication of the user card, we store in a memory location associated with the logical channel, contextual data relating to the authentication step, said location memory in a memory of the security module, - the card is removed from the terminal.

According to a second object of the present invention, this solution is characterized in that the security module comprises:

means for allocating a logical channel to said terminal into which the card is inserted, a memory location associated with the logical channel capable of storing contextual data relating to each authentication step of the user card, said memory location is found in a memory of the security module. Thus, as will be seen in detail below, the data management method as well as the security module of the invention make it possible to manage several public telephones in parallel by means of a security module. To this end, contextual data is stored defining the state in which a set of user cards is located at a given time during a connection session of said cards, for several telephones, the data being saved in a memory. of the security module.

The description which follows with reference to the appended drawings, given by way of nonlimiting example, will make it clear what the invention consists of and how it can be implemented.

FIG. 1 is a diagram showing a security module, a terminal and a user card for implementing the method according to the invention. FIG. 2 is a diagram of the security module of FIG. 1 comprising several memory locations.

FIG. 3 is a diagram showing a first communication between the security module and the terminal of FIG. 1.

FIGS. 4a, 4b, 4c, 4d and 4e are diagrams representing a memory location of the security module of FIG. 2.

FIG. 5 is a diagram showing a memory location of the security module of FIG. 2.

FIG. 6 is a diagram showing a second communication between the security module and the terminal of FIG. 1. The present description of the invention relates to the example of integrated circuit cards. By integrated circuit card is meant any portable object, card in ISO format or not, subscriber identification module, electronic label, badge, etc.

It will be noted that the term “introduction” of a card into a terminal, used subsequently, generally means " cooperation ". The invention relates both to a card with a contact interface which requires a physical introduction into the terminal, as well as a card with a contactless interface which are able to communicate with the terminal without physical contact with the latter (by radio frequency. ..) or a card with the two interfaces.

In FIG. 1 is shown a security SAM module, a terminal P and a CARD user card. Terminal P is a public telephone. The SAM module comprises a memory comprising at least one memory location M. Preferably, the memory of the SAM security module is a non-volatile EEPROM memory. Preferably, the SAM security module comprises several memory locations M. As shown in FIG. 2, advantageously, the memory locations M are placed contiguously in a CHANNEL file of the non-volatile memory EEPROM, and, a chronological counter RECMAN is associated at a memory location M as well as an allocation area CN. The CN allocation area as well as the RECMAN chronological counter have respective initial values VI and V2. The SAM security module also includes at least one ISSUER file comprising a MASTER master key and a cumulative CBCPT counter of units. Advantageously, the module includes several ISSUER files. Each ISSUER file corresponding to a type of cards issued.

When a user wants to telephone, he introduces his CARD card into the public telephone P. Before initiating a communication, a first authentication A is carried out by means of the SAM security module, via the telephone P and then the communication.

The first authentication A comprises the steps described below, as shown in FIG. 3. In a first step, an identifier ID of the user card is read, said identifier being unique for each card.

In a second step, an available LC logical channel is sought and a logical channel for the public telephone P in which the user card CARD is located is allocated in the SAM security module. Prior to allocation, an LC logical channel is sought by means of a first GETCHANNELSTATUS command sent from the public telephone P to the SAM security module. A logical channel LC includes an identifier NB. Said module returns a list of all the channels used, advantageously their identifier NB. We deduce the channels that are available and choose one of the available channels. After allocation, a memory location M is associated with the logical channel LC by writing the identifier NB of the logical channel LC allocated in the area CN for allocation of the chosen memory location M. Thus, the memory location M is no longer free.

The lifetime of the non-volatile EEPROM memory depends on the number of registrations made. In order to avoid associating a memory location M of the non-volatile EEPROM memory with a logical channel LC, for example, in ascending order, and consequently of always using the same locations, the chronological counter RECMAN of each location is used. memory M as described below. When a LC logical channel is closed, the value of the RECMAN chronological counter of the associated memory location M is incremented, relative to the maximum value of all the chronological counters of the memory locations M. The oldest memory location M is the one with the smallest RECMAN time counter value. Thus, the oldest free memory location M is associated with a logical channel LC. As shown in FIG. 4a, the CHANNEL file comprises four memory locations M l, M2, M3 and M4 used. Their counters RECMAN chronological values have an initialization value V2 equal to zero.

In this example, the value of a RECMAN chronological counter is incremented by one. As shown in FIG. 4b, the channel associated with the third location M3 is released. Its RECMAN3 counter is incremented by one and worth one. As shown in FIG. 4c, the channel associated with the second location M2 is released. His counter

RECMAN2 is incremented by one compared to the third counter. Its value is two. The channel associated with the fourth memory location M4 is released, its counter RECMAN4 is worth three, as shown in FIG. 4d. finally, a logical channel LC with identifier NB3 is allocated and the oldest free memory location M is associated, ie, as shown in FIG. 4e, the third memory location M3. Thus, the method of the present invention allows, on the one hand, to avoid always choosing the same memory location M to write data there as we will see later, and, on the other hand, not to be restricted to the number of memory locations M for the choice of LC logical channel identifiers to be allocated. We can thus have the choice between, for example, two hundred and fifty five LC channel identifiers while having only ten memory locations M. Of course, this memory management method described above can be applied to any application other than that of telephony.

In a third step, in the SAM security module, the secret key KEY of the CARD card is recalculated, using the identifier ID of said card and a master key MASTER of said SAM module. This step is also called the key diversification step. In order to choose the MASTER master key, in the SAM module, an ISSUER file is selected during the step of reading the identifier of the user card, the correlation being made between the type of cards and the master key by means of the identifier of said user card. The allocation of the LC logical channel and the diversification of the key are done by means of a second DIVERSIFYKEY command sent from the public telephone P to the SAM security module. Said second command takes into account in particular the identifier NB of the channel allocated to the public telephone P, an identifier ALGOID2 of a diversification algorithm ALGO2, an identifier of the master key MASTER used and, where appropriate, a diversifier RAND.

In a fourth step, as shown in FIG. 5, the contextual data DATA relating to the authentication step A is stored in the memory location M associated with the allocated logical channel LC. The contextual data DATA comprises an identifier ALGOID 1 an ALGO 1 signature algorithm, the identifier ID of the CARD user card, the identifier of the MASTER master key used, the diversified key KEY, an ABACUS abacus of the CARD user card, and, status data STATE .... The ABACUS abacus has a first VO value. It allows the units used in the CARD user card to be counted, the STATE state data makes it possible to manage in the SAM security module a sequence of commands in order to memorize the state of the SAM module at a given instant, and this for a LC logical channel given. Thus, according to the state in which we are, we know what are the authorized commands and in what state we are after the execution of one of the commands according to the result of said execution. According to a particular embodiment, the SAM module comprises a table in which a number and a set of bytes are assigned to each state. An authorized command is represented by one of the bytes. The first quartet of the byte includes the number of the state in which we are after execution of the command, if there has been no error. The second quartet includes the number of the state in which we are when there has been an error (not shown). If another user uses a second CARD in a second P-phone, the second card can be validated using the SAM module, for example, after a first authentication of a first user card. The contextual data of the first card is not lost, we can continue to manage the first card. The method of said invention thus allows, thanks to this management of contextual data by the SAM security module, to execute different authentication sessions in parallel, an authentication session corresponding to a call duration and consequently manage multiple public telephones P by means of the security module SAM, a public telephone P having an allocated logical channel LC and an associated memory location M.

Finally, in a last step, we send a random number RAND to the card, we store said random number in the memory location M associated with the allocated logical channel LC, we calculate in the card a cryptogram by encrypting the secret key KEY using in particular the ALGO 1 signature algorithm, the random number RAND, and, the cryptogram is sent to the security module SAM (not shown). In said SAM module, the value of the cryptogram is checked by means of the secret key KEY recalculated during the third step.

Thus, the first authentication A carried out, the communication can be established. The ABACUS chart on the card is updated according to the number of units used during communication. The value of the ABACUS abacus is read in order to verify that the abacus has been updated. Thereafter, a second authentication A is carried out which corresponds to the last step of the first authentication A described above.

Said second authentication A takes into account the value of the abacus abacus read previously, the identifier ALGOID 1 of the ALGO 1 signature algorithm used and the ID identifier of the card, which have been saved in the memory location M. In the case where the same RAND random number is used, the steps concerning said random number are not useful since the latter is stored in the memory location M.

Subsequently, in the memory location M associated with the logical channel LC allocated, the contextual data DATA such as the new value VN of the abacus ABACUS, the new state data STATE, and, if necessary, the new RAND random number generated, said new state data replacing the old ones. The same is true for the new random RAND number, if applicable. If a power off of the SAM module occurs, said second authentication A is performed again.

This second authentication A makes it possible to verify that no fraudster has used a pirate card to telephone. In fact, if a user introduces a fraudulent card, the cryptogram calculated by said card and returned to the SAM module is erroneous since it is different from that calculated in said SAM module. The identifier of the fraudulent card is different from that of the valid card previously inserted in the public telephone P, as is the value of the ABACUS chart.

When the communication is finished, the CARD card is removed from the public telephone P. The allocated logical channel LC is no longer useful. Also, the logical channel LC associated with the terminal P is closed. To this end, the area CN allocation of the memory location M associated with the initialization value VI is initialized and the chronological counter RECMAN is updated. If necessary, the contextual data DATA is deleted in the memory location M associated with the logical channel LC which is freed. The method of the present invention has an advantage according to which the number of units used per type of card is counted in the SAM security module in an optimized manner. Indeed, as shown in Figure 6, instead of performing an update for each unit used, it suffices to update the cumulative counter CBCPT of units of an ISSUER file of the SAM module by subtracting the new value VN of the abacus ABACUS of the card of the first value VO of said abacus, the new value VN being stored in the memory location M after each new second authentication A. When the subtraction has been made, the first value VO is replaced by the second value VN memorized, for the next second authentication A. This update is triggered by means of a third INCBILLING command taking into account a channel identifier NB corresponding to an ISSUER file and public telephone P used, said command being sent from the public telephone P to the SAM module.

It will be noted that when a public telephone P comprises said security module SAM, the management of the channels described above does not apply since only one logical channel is used, and, the contextual data DATA are stored in a volatile memory. RAM.

Of course, the invention is in no way limited to the field of telephony, it can extend to other fields in which a terminal administration system is implemented, such as for example an administration system of parking meters.

Claims

1 - Data management method, by a security module (SAM), of a user card (CARD) capable of being inserted into at least one terminal (P), said card being subjected to at least one authentication (A) by said security module (SAM), characterized in that it comprises the steps according to which:

the card (CARD) is introduced into a terminal (P), a logical channel (LC) is allocated in said security module (SAM) to said terminal (P),

- each authentication (A) of the user card (CARD), contextual data (DATA) relating to the authentication step (A) is stored in a memory location (M) associated with the logical channel (LC) memory location (M) located in a memory of the security module (SAM),

- the card (CARD) is removed from the terminal (P).

2 - Method according to claim 1, characterized in that the memory of the security module (SAM) is a non-volatile memory (EEPROM). 3 - Method according to claims 1 or 2, characterized in that the oldest memory location (M) is associated with a free logical channel (LC).

4 - Method according to one of the preceding claims, characterized in that a chronological counter (RECMAN) is associated with a memory location (M).

5 - Method according to claims 3 and 4, characterized in that the oldest memory location (M) is the one whose value of the chronological counter (RECMAN) is the smallest. 6 - Method according to one of the preceding claims, characterized in that it comprises an additional step according to which: prior to allocation, a logical channel (LC) is sought by means of a first command

(GETCHANNELSTATUS).

7 - Method according to one of the preceding claims, characterized in that the security module (SAM) comprises several memory locations (M). 8 - Method according to one of the preceding claims, characterized in that it comprises an additional step according to which: the logical channel (LC) associated with the terminal (P) is closed.

9 - Method according to claim 8, characterized in that when a logical channel (LC) is closed, the value of the chronological counter (RECMAN) of the associated memory location (M) is incremented, relative to the maximum value of all the chronological counters of the memory locations (M).

10 - Method according to one of the preceding claims, characterized in that a memory location (M) is associated with a logical channel (LC) by entering an identifier (NB) of the logical channel (LC) allocated in a zone (CN ) allocation of the memory location (M).

11 - Security module (SAM) intended to manage a user card (CARD) inserted in at least one terminal (P), said card being able to be subjected to at least one authentication (A) by said security module (SAM) , characterized in that it comprises: - means for allocating a logical channel (LC) to said terminal (P) into which the card (CARD) is inserted, a memory location (M) associated with the logical channel (LC) capable of storing contextual data (DATA) relating to each authentication step (A) of the user card (CARD), said memory location (M) being in a security module memory (SAM).

12 - Module according to claim 11, characterized in that the memory of the security module (SAM) is a non-volatile memory (EEPROM).

13 - Module according to claims 11 or 12, characterized in that the oldest memory location (M) free is associated with a logic channel (LC).

14 - Module according to one of the preceding claims l i to 13, characterized in that a chronological counter (RECMAN) is associated with a memory location (M). 15 - Module according to claims 13 and 14, characterized in that the oldest memory location (M) is the one whose value of the chronological counter (RECMAN) is the smallest.

16 - Module according to one of the preceding claims l i to 15, characterized in that it further comprises a first command (GETCHANNELSTATUS) capable of seeking a logical channel (LC) prior to allocation.

17 - Module according to one of the preceding claims 1 1 to 16, characterized in that it comprises several memory locations (M). 18 - Module according to one of the preceding claims 1 1 to 17, characterized in that it further comprises means for closing the logic channel (LC) associated with the terminal (P).

19 - Module according to one of the preceding claims lia 18, characterized in that it further comprises means for incrementing the value of the chronological counter (RECMAN) by the associated memory location (M), compared to the maximum value of all the chronological counters of the memory locations (M).

20 - Module according to one of the preceding claims 1 1 to 19, characterized in that it further comprises means for associating a memory location (M) with a logical channel (LC), said means being able to register an identifier (NB) of the logical channel (LC) allocated in an area (CN) of allocation of the memory location (M).