Method of mobile radio unit registration and IC card registration for a mobile radio communication system.

FIELD OF THE INVENTION

The present invention relates to a method of registering an ID (identification) information containing type mobile unit for use in a mobile communications network and a method of registering an IC (integrated circuit) card used with an IC card insertion type mobile unit for use in a mobile communications network. The invention also relates to an ID information containing type mobile unit, an IC card, and an IC card insertion type mobile unit implementing such methods.

BACKGROUND OF THE INVENTION

For mobile units used for mobile telephones such as car telephones, portable telephones, etc., Japan currently employs a leasing system under which the subscriber leases the mobile equipment from the communications carrier that provides the telephone network, but a purchase system of the mobile equipment is expected to be introduced soon. While it is hoped that the introduction of the purchase system will help to further increase the use of mobile telephones, such problems as illegal duplication of mobile units (clone mobile units) are expected to arise. In fact, other countries where purchase plans are employed are facing such problems.

There are two types of information stored in a memory of a mobile unit: information, such as built-in software, whose contents are identical with other mobile units of the same model, and information different for each individual mobile unit and used to authenticate the mobile unit to the communications network for connection. The former information need not be read out or written in from the outside, and also, the amount of information is large; therefore, it is so designed that external readout or write-in is difficult or impossible. On the other hand, the latter individualized information includes information concerning the telephone number (Mobile Subscriber Number: MSN) assigned to each subscriber of the telephone network, the mobile unit number (Mobile Station Identity: MSI) for identifying the mobile unit, the authentication key (MSN-key) for the communications network to authenticate the subscriber, and the authentication key (MSI-key) for the communications network to authenticate the mobile unit. The amount of such personal information is relatively small. After the mobile unit purchase system is put into effect, it is required when a contract is made between the communications carrier and the subscriber who purchased the mobile unit, that after sale of the product, personal information should be written into the mobile unit for registration with the communications carrier as soon as possible. Therefore, there must be a capability that such personal information is quickly written in and read out from the outside. Furthermore, the personal information must be alterable to allow for a possible future change in the contents of the contract.

In the case of an ID containing type mobile unit in which such personal information is stored in a nonvolatile memory such as an EEPROM contained in the mobile unit, a stand-alone ROM writer is connected to write the information into the internal EEPROM when the contract is made. It is desirable, from the standpoint of promoting the sales of mobile units, that the ROM writer be installed at every mobile unit dealer who is authorized under contract with the communications carrier so that the user who purchased the mobile unit can have the unit registered on the spot without having to take the unit to the communications carrier for registration.

Another method of sale which is desirable from the standpoint of sales promotion is to sell mobile units with no personal information written therein at mass-volume retail stores, so that the user who purchased one from such a store takes his mobile unit to an authorized dealer having the ROM writer and has the personal information written into the mobile unit for registration upon making a contract.

To make such a method of sale possible, the mobile unit must be designed so that personal information can be written in and read out from outside the unit. However, the fact that mobile units with no personal information written in are sold on the market and that the personal information stored in each mobile unit can be read out, means that duplicate units that cannot be distinguished by the communications network can be made easily by reading out the personal information and writing it into other mobile units with no personal information previously written therein.

Even if the personal information is stored in encrypted form so that the contents cannot be recognized, duplicates of mobile units that can be connected to the communications network can be made by simply copying the same contents into other mobile units of the same model. Even if perfect protection can be provided by some means against read out attempts, it is possible to make duplicate units by reading out personal information from a mobile unit of a previous model from which the personal information can be read out, and by writing it into other mobile units with no personal information written therein. Such illegal duplications of registered mobile units would not only make it impossible to collect basic charges that could otherwise be collected, but cause a problem that when a number of such indistinguishable mobile units are simultaneously connected to the communications network, the registration of mobile unit locations would become confused, thus disrupting the communications network system.

To facilitate the contract and registration procedures at the carrier's authorized dealers where the ROM writer is installed, it is desirable that the ROM writer be connected to a terminal installed at the communications carrier via a communication line so that the contract and registration procedures can be performed on-line. This, however, gives rise to the possibility that someone may intercept the communication line. It is therefore necessary to provide some measures so that if intercepted, duplication of mobile units cannot be made by using the intercepted information.

Furthermore, provisions must be made so that even if information known only to the communications carrier or the mobile unit manufacturer leaks out for some reason, duplication of mobile units cannot be made by using the information from one party alone unless the information from the other party is combined with it.

Moreover, for the mobile unit to be connected to the ROM writer via a cable, the mobile unit needs to be provided with a connector for cable connection with the ROM writer; this prevents a reduction in size of the mobile unit. Further, if the type of connector is different for each mobile unit model, the dealer needs to have as many ROM writers as the number of mobile unit models that the dealer carries.

On the other hand, it is planned that the personal information will be stored in an IC card instead of writing it directly into a mobile unit so that the IC card is inserted into a mobile unit for use in communication, allowing the shared use of one mobile unit by plurality of subscribers, or conversely, allowing one subscriber to use a plurality of mobile units. In this case also,the IC card must be made secure from illegal readout and write-in (dead copy), and furthermore, measures must be taken so that illegal duplication of the IC card cannot be made by using the information from one party alone, the communication carrier or the manufacturer, as in the case of the built-in ID type mobile unit.

Since each IC card is identical in physical shape, it can be inserted into any mobile unit. However, when the IC card is inserted into a mobile unit that cannot be connected to the communications network or that is not permitted to be connected to the communications network, such a mobile unit must not operate and transmit illegal radiowaves.

One way this can be accomplished is by storing information on the IC card that restricts the use only to the mobile units approved by the communications carrier for connection. In this case, when an additional mobile unit is approved for connection after the registration of the IC card, a request will have to be made to the communications carrier or its authorized dealer to have additional information written to the IC card in order that the additional mobile unit is able to be used. This imposes a cumbersome procedure on the subscriber.

SUMMARY OF THE INVENTION

Accordingly, one object of the present invention is to provide a method of mobile unit registration capable of preventing illegal duplication of mobile units.

Another object of the invention is to provide a method of mobile unit registration that does not require the provision of a connector for the connection with a ROM writer for mobile unit registration, and that does not need different ROM writers for different models.

Another object of the invention is to provide a method of IC card registration for an IC card insertion type mobile unit, wherein an additional mobile unit approved after the registration of the IC card can be registered for use with the IC card without having to undergo a cumbersome procedure.

Another object of the invention is to provide a mobile unit, IC card, and IC card insertion type mobile unit implementing the above methods.

According to the present invention, there is provided a method of registering a mobile unit for use in a mobile communications network, comprising the steps of: determining identification information for identifying each individual mobile unit; generating first information data by signature-encrypting the identification information with a carrier secret key of a communications carrier providing the mobile communications service; and writing the identification information into a memory module contained in the mobile unit by entering an identification information write command, containing the first data, into the memory module from which the identification information can be read out only when an identification information readout command, containing a mobile unit secret key of a manufacturer of the mobile unit, is entered.

According to the present invention, there is also provided a method of registering a mobile unit for use in a mobile communications network, comprising the steps of: coupling a mobile unit registration terminal to the mobile unit by power-conserving radio; sending identification information for identifying each individual mobile unit from the mobile unit registration terminal to the mobile unit by the power-conserving (low power) radio; and storing the identification information into the mobile unit.

According to the present invention, there is also provided a method of registering an IC card for an IC card insertion type mobile unit for use in a mobile communications network, comprising the steps of: determining identification information for identifying each individual IC card; generating first information data by signature-encrypting the identification information with a secret carrier key of the communications carrier which is providing the mobile communications network; and writing the identification information into the IC card by entering an identification information write command which contains the first information data, into the IC card from which the identification information can be read out only when an identification information readout command, which contains a mobile unit secret key of the manufacturer of the mobile unit, is entered.

According to the present invention, there is also provided a mobile unit for use in a mobile communications network, comprising: a memory module into which identification information for identifying each individual mobile unit is written only when an identification information write command is entered that contains first information data generated by signature-encrypting the identification information with a secret carrier key of the communications carrier providing the mobile communications network, and from which the identification information is read out only when an identification information readout command, which contains a mobile unit secret key of the manufacturer of the mobile unit, is entered; means for writing the identification information into the memory module by entering the identification information write command; and means for reading out the identification information by entering the identification information readout command into the memory module.

According to the present invention, there is also provided a mobile unit for use in a mobile communications network, comprising: means for being coupled to a mobile unit registration terminal by power-conserving radio; means for receiving identification information for registration of the mobile unit from the mobile unit registration terminal by the power-conserving radio; and means for storing the identification information.

According to the present invention, there is also provided an IC card for an IC insertion type mobile unit for use in a mobile communications network, comprising: an input/output terminal; means for holding identification information used for connection to the mobile communications network; means for decrypting identification information and writing the same into the identification information holding means when an identification information write command, which contains the identification information, signature-encrypted with a secret carrier key of the communications carrier providing the mobile communications network, is entered via the input/output terminal; and means for reading out the identification information from the identification information holding means and outputting the same at the input/output terminal when an identification information readout command is entered via the input/output terminal, which command contains a mobile unit secret key of the manufacturer of the mobile unit for a model that can be used with the IC card inserted therein.

According to the present invention, there is also provided an IC card insertion type mobile unit for use in a mobile communications network, comprising: means for storing a mobile unit secret key of the manufacturer of the mobile unit; and means for reading identification information from an IC card inserted into the mobile unit by entering an identification information readout command, which contains the mobile unit secret key stored in the storing means, into the IC card.

According to the present invention, there is also provided an IC card insertion type mobile unit for use in a mobile communications network, comprising: means for storing signature data generated by signature-encrypting a mobile unit public key corresponding to a mobile unit secret key of the manufacturer of the mobile unit by using a secret carrier key of the communications carrier providing the communications network; and means for reading identification information from an IC card inserted into the mobile unit by entering an identification information readout command, the command containing the signature data stored in the storing means, into the IC card.

BRIEF DESCRIPTION OF THE DRAWINGS

<ul id="ul0001" list-style="none"><li>Figure 1 is a block diagram showing the configuration of an ID containing type mobile unit according to one embodiment of the present invention;</li><li>Figure 2 is a block diagram showing the configuration of a COB device shown in Figure 1;</li><li>Figure 3 is a diagram schematically showing the data stored in an EEPROM shown in Figure 1;</li><li>Figure 4 is a diagram for explaining the outline of a mobile unit registration method according to the present invention;</li><li>Figure 5 is a block diagram showing a setup for on-line registration of a mobile unit with a communications carrier;</li><li>Figure 6 is a block diagram showing the configuration of a dealer's terminal 72 shown in Figure 5;</li><li>Figure 7 is a diagram showing the first half of a sequence for new mobile unit registration in the setup shown in Figure 5;</li><li>Figure 8 is a diagram showing the second half of the sequence for new mobile unit registration;</li><li>Figure 9 is a diagram showing the first half of a sequence for updating mobile unit's personal information;</li><li>Figure 10 is a diagram showing the second half of the sequence for updating mobile unit's personal information;</li><li>Figure 11 is a diagram showing the first half of a sequence for updating the contents of additional services;</li><li>Figure 12 is a diagram showing the second half of the sequence for updating the contents of additional services;</li><li>Figure 13 is a diagram showing the first half of a sequence for updating a credit card number;</li><li>Figure 14 is a diagram showing the second half of the sequence for updating a credit card number;</li><li>Figure 15 is a diagram for explaining a mobile unit registration method according to another embodiment of the present invention;</li><li>Figure 16 is a block diagram showing the configuration of a mobile unit 112 shown in Figure 15;</li><li>Figure 17 is a block diagram showing the configuration of a dealer's terminal 110 shown in Figure 15;</li><li>Figure 18 is a perspective view showing an external appearance of the dealer's terminal 110;</li><li>Figure 19 is a block diagram showing the configuration of an IC card insertion type mobile unit according to another embodiment of the present invention;</li><li>Figure 20 is a block diagram showing the configuration of an IC card 130;</li><li>Figure 21 is a diagram schematically showing the data stored in an EEPROM shown in Figure 19;</li><li>Figure 22 is a diagram for explaining the outline of an IC card registration method according to the present invention;</li><li>Figure 23 is a block diagram showing the configuration of an IC card registration terminal;</li><li>Figure 24 is a perspective view showing an external appearance of the IC card registration terminal;</li><li>Figure 25 is a block diagram showing the configuration of a COB device 172 shown in Figure 23;</li><li>Figure 26 is a diagram schematically showing the data stored in an EEPROM 146 shown in Figure 23;</li><li>Figure 27 is a diagram showing the outline of a process up to the registration of the IC card registration terminal;</li><li>Figure 28 is a diagram showing a setup for a registration procedure for the IC card registration terminal;</li><li>Figure 29 is a diagram showing the first half of a registration sequence for the IC card registration terminal;</li><li>Figure 30 is a diagram showing the second half of the registration sequence for the IC card registration terminal;</li><li>Figure 31 is a diagram showing a setup for an IC card registration procedure;</li><li>Figure 32 is a diagram showing a processing sequence for the authentication of the IC card registration terminal;</li><li>Figure 33 is a diagram showing the first portion of a processing sequence for new IC card registration;</li><li>Figure 34 is a diagram showing the middle portion of the processing sequence for new IC card registration;</li><li>Figure 35 is a diagram showing the last portion of the processing sequence for new IC card registration;</li><li>Figure 36 is a diagram showing the first portion of a processing sequence for updating IC card's personal information;</li><li>Figure 37 is a diagram showing the middle portion of the processing sequence for updating IC card's personal information;</li><li>Figure 38 is a diagram showing the last portion of the processing sequence for updating IC card's personal information;</li><li>Figure 39 is a diagram showing the first portion of a processing sequence for updating the contents of additional services registered on the IC card;</li><li>Figure 40 is a diagram showing the middle portion of the processing sequence for updating the contents of additional services registered on the IC card;</li><li>Figure 41 is a diagram showing the last portion of the processing sequence for updating the contents of additional services registered on the IC card;</li><li>Figure 42 is a diagram showing the first portion of a processing sequence for changing the credit card number registered on the IC card;</li><li>Figure 43 is a diagram showing the middle portion of the processing sequence for changing the credit card number registered on the IC card;</li><li>Figure 44 is a diagram showing the last portion of the processing sequence for changing the credit card number registered on the IC card;</li><li>Figure 45 is a diagram schematically showing the data stored in an EEPROM 20' of an IC card insertion type mobile unit according to another embodiment of the present invention;</li><li>Figure 46 is a diagram showing an example of a sequence for reading personal information from an IC card loaded into the mobile unit; and</li><li>Figure 47 is a diagram showing another example of a sequence for reading personal information from an IC card loaded into the mobile unit.</li></ul>

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 is a block diagram showing the hardware configuration of an ID containing type mobile unit according to one embodiment of the present invention. A radio unit 10, a microphone 12, and a speaker 14 are used to transmit and receive control signals and voice signals to and from a base station (not shown), the radio unit 10 being controlled by a central processing unit (CPU) 16 to carry out the functions of a mobile unit. Connected to the CPU 16 are a random access memory (RAM) 18, an electronically erasable programmable read-only memory (EEPROM) 20, a chip-on-board (COB) device 22, a signal controller 24,a keypad 26, and a display 28.

In accordance with control programs contained in the EEPROM 20, the CPU 16 controls the radio unit 10 and also performs control to register the mobile unit to a communications network and have its personal information written into the COB device 22. The RAM 18 temporarily stores data for various control operations. The RAM 18 also stores the personal information read out of the COB device for connection to the communications network. The personal information includes a fixed pattern for verifying the correctness of its contents. The signal controller 24 provides an interface between the CPU 16 and a dealer's terminal (to be described later) connected through an input/output terminal 29 for the writing of the personal information. They keypad 26 is used to accept inputs for personal information write operations as well as inputs for communication operations. The display 28 not only displays status associated with communication operations of the mobile unit, but is also used during personal information write operations.

Figure 2 is a block diagram showing the configuration of the COB device 22 shown in Figure 1. The COB device 22 comprises a CPU 30, a RAM 32, a ROM 34, and an EEPROM 36; the whole structure is sealed with resin, and only a power supply terminal and an input/output terminal 38 for communication between the CPU 30 and the CPU 16 of the mobile unit are exposed. The structure is such that the contents of the internal EEPROM 36 cannot be read out or written in unless specific commands are input to the CPU 30 via the input/output terminal 38.

The ROM 34 contains a control program 40 for the CPU 30, a password 42, and a common public key KE_COB 44 corresponding to a common secret key KD_COB determined through consultation among all communication carriers concerned. The password 42 is stored to allow the user to enter the COB device 22 into a mode (supervisor mode) to carry out a specific command (to be described later) only when a value that matches the password 42 is entered via the input/output terminal 38.

In the description given hereinafter, a secret key is denoted by KD and its corresponding public key is denoted by KE with the same subscript as attached to KD. The secret key KD and its corresponding public key are determined, e.g., in accordance with the RSA (Rivest-Shamir-Adleman) cryptosystem, but the present invention is not limited to this cipher system. It will be appreciated that the secret-key cryptosystem can also be applied analogically. In the RSA cryptosystem, when the encrypt calculation for converting a plaintext M into a ciphertext C with the public key KE is expressed as <maths id="math0001" num=""><math display="inline"><mrow><mtext>C = E (KE, M)   (1)</mtext></mrow></math><img file="EP0652681A2_D0001.tif" /></maths> then the decrypt calculation for converting the ciphertext C back into the plaintext M is expressed as<maths id="math0002" num=""><img file="EP0652681A2_D0002.tif" /></maths> The signature encryption in a digital signature is expressed as <maths id="math0003" num=""><math display="inline"><mrow><mtext>C = E (KD, M)   (3)</mtext></mrow></math><img file="EP0652681A2_D0003.tif" /></maths> and the decrypt process is expressed as<maths id="math0004" num=""><img file="EP0652681A2_D0004.tif" /></maths>    KE_COB 44 is stored in order to enable a carrier public key KE_Cj (to be described later) which have been signature-encrypted with KD_COB to be decrypted and then to be written into the EEPROM 36. That is, KE_COB is stored so that only the person who knows KD_COB corresponding to KE_COB is authorized to write KE_Cj. These contents are written into the ROM 34 in the manufacturing process of the COB device 22 during the manufacture of the COB device before it is shipped to the mobile unit manufacturer. The contents are unalterable. The control program 40 includes programs for controlling input/output operations via the input/out terminal 38 as well as programs for encrypt/decrypt calculations expressed by equations (1) to (4), and all encrypt/decrypt operations in the mobile unit are performed within the COB device 22.

The EEPROM 36 can store personal information such as MSN, MSI, etc., a carrier public key KE_Cj 50 corresponding to a carrier secret key KD_Cj known only to the communications carrier, and a mobile unit public key KE_MSNi 52 corresponding to a mobile unit secret key KD_MSNi known only to the manufacturer of the mobile unit. The carrier secret key KD_Cj/carrier public key KE_Cj pair is determined for each communications carrier; when one communications carrier provides a plurality of communications networks, the key pair is determined for each communications network. The mobile unit secret key KD_MSNi/public key KE_MSNi pair is determined for each mobile unit model.

Of the contents of the EEPROM 36, the carrier public key KE_Cj 50 is written into the EEPROM 36 in the manufacturing process of the mobile unit. If one mobile unit model is approved by a plurality of communications carriers for connection, the same number of KE_Cj's as the number of carriers are written. The mobile unit public key KE_MSNi 52 and the personal information 48 are written when the mobile unit is registered to the communications network. The personal information 48 includes a fixed pattern which is compared with fixed patterns (to be described later) in the EEPROM 20 when the personal information is read out by the CPU 16 of the mobile unit; only when a match is found with one of them, it is decided that the correct personal information has been read out. This serves to avoid wasteful communication with the communications network even when wrong information is written in the COB 22.

Figure 3 schematically shows the data stored in the EEPROM 20 of the mobile unit shown in Figure 1. The EEPROM 20 contains a control program 54 for the CPU 16, the aforementioned fixed patterns 56 which are compared with the fixed pattern read into the RAM 18 to verify the correctness, a flag 58 indicating whether or not personal information has been written in the COB device 22, and a mobile unit secret key KD_MSNi 60 and its corresponding mobile unit public key KE_MSNi 62. The fixed pattern 56 may be different for different communications carriers; therefore, multiple fixed patterns are stored. When the fixed pattern read into the RAM 18 matches any one of these patterns, then it is decided that the correct personal information is stored in the COB device 22.

The mobile unit secret key KD_MSNi and public key KE_MSNi are stored with their contents shuffled so that they cannot be easily recognized by reading out the contents of the EEPROM 20 and comparing them between different mobile units. The control program 54, fixed patterns 56, mobile unit secret key KD_MSNi, and mobile unit public key KE_MSNi are written during the manufacture of the mobile unit, while the flag 58 is caused to change state when the mobile unit is registered to the communications network.

Table 1 is a listing of commands that are accepted by the internal COB device 22 of the ID containing type mobile unit shown in Figures 1 and 2. <tables id="tabl0001" num="0001"><img file="EP0652681A2_D0005.tif" /></tables>

Referring to Table 1, when the command of item No. 1, containing a designated password, is entered, the entered password is compared with the password 42 contained in the ROM 34, and when they match, the unit goes into the supervisor mode. The command of item No. 4 is valid only in the supervisor mode. In the supervisor mode, when the command of item No. 4, containing E(KD_COB, KE_Cj) expressing the carrier public key KE_Cj encrypted with the common secret key KD_COB, is entered, decryption is performed using the common public key KE_COB held in the ROM 34 and KE_Cj is written into the EEPROM 36, upon which the unit returns to the normal mode. If, at this time, carrier public keys of other carriers are already stored, the KE_Cj is added to the bottom of the contents of the table. In the RSA cryptosystem, if KE_Cj is 0 or 1, the conversion result will be 1 or no change and the contents of the key can be easily known; therefore, if KE_Cj is 0 or 1, the write request will not be accepted. In other encryption systems, any value inappropriate to the encryption system employed will not be accepted. The command of item No. 6 is used to write the mobile unit public key KE_MSNi into the EEPROM 36 in the COB device 22. When the command of item No. 6, containing the carrier public key KE_Cj and E(KD_Cj, KE_MSNi) expressing the mobile unit public key KE_MSNi signature-encrypted with the carrier secret key KD_Cj is entered, if the entered KE_Cj matches one of the stored KE_Cj's, the entered E(KD_Cj, KE_MSNi) is decrypted with KE_Cj and the resulting KE_MSNi, is stored. The command of item No. 8 is used to write in the personal information. The command of item No. 8 contains the carrier public key KE_Cj, the mobile unit secret key KD_MSNi, E(KE_MSNi, E(KD_Cj, ID)) which expresses the personal information ID signature-encrypted with KD_Cj with the result further encrypted with KE_MSNi, and E(KD_Cj, RDM) which expresses the random number RDM (to be described later) signature-encrypted with KD_Cj. When this command is entered, if the entered KE_Cj matches one of the stored KE_Cj's, and if the RDM obtained by decrypting E(KD_Cj, RDM) with KE_Cj matches the RDM stored in the RAM 32 in the COB device 22, then the personal information obtained by decrypting the entered E(KE_MSNi, E(KD_Cj, ID)) with KD_MSNi and KE_Cj, is written into the EEPROM 36. The command of item No. 9 is used to read out the personal information. When the command of item No. 9, containing KD_MSNi, is entered, the stored personal information is encrypted with the stored KE_MSNi and decrypted with the entered KD_MSNi, i.e., ID = E(KD_MSNi, E(KE_MSNi, ID)) is calculated, and the result of the calculation is output as the personal information. By entering the command of item No. 10, the random sequence RDM used in the command of item No. 8 is output, and at the same time, is stored into the RAM 32. The command of item No. 11 is used to read out the carrier public key KE_Cj stored in the COB device 22. The command of item No. 11 contains the integer j that specifies the stored position of the requested KE_Cj, an arbitrary integer A which is neither 0 nor 1 (condition for RSA cryptosystem), and E(KD_Cj, A) expressing A signature-encrypted with KD_Cj. When this command is entered, if the result obtained by decrypting E(KD_Cj, A) with the KE_Cj stored in the jth position matches the entered A, then KE_Cj is output. The command of item No. 12 is used to perform a conversion operation using the conversion operating program stored in the COB device 22. When the command of item No. 12, containing the key K and integer A, is entered, E(K, A) is calculated and output.

The commands of item Nos. 6 and 8 each contain the carrier public key KE_Cj in order to select one of the stored KE_Cj's. Therefore, like the IC card to be described later, when no more than one KE_Cj is stored, i.e., when connection for services is limited to only one communications network, there is no need to enter KE_Cj. In entering the command of item No. 8 E(KD_Cj, ID), i.e., an ID with a digital signature encrypted with KD_Cj, is encrypted with KE_MSNi, and the result is entered. This is to prevent the ID from being deciphered by an eavesdropper when the ID is transmitted via a public network. If this is not a concern, or if it is to be written in a secret manner, data in the form of E(KD_Cj, ID) may be written in.

Figure 4 is a diagram for explaining the outline of a mobile unit registration method according to the present invention. First, the password PWD, common public key KE_COB, control programs and other data to be written into the ROM in the COB device are supplied in the form of a load module from the communications carrier to the COB manufacturer (step a). The data are written into the ROM to produce the COB device (step b), which is then shipped. At this stage, since the mobile unit in which the COB device will be installed, i.e., the communications carrier that provides the service is not known, only the common public key KE_COB is written as the public key. When the COB device is delivered, the mobile unit manufacturer receives the password PWD and signature data E(KD_COB, KE_Cj), i.e., the carrier public key KE_Cj with a signature encrypted with the common secret key KD_COB, from the communications carrier (step c), and writes the KE_Cj into the COB device by using the commands of item Nos. 1 and 4 shown in Table 1 (step d). At this time, if the mobile unit in which the COB device is to be installed is intended for use in more than one communications network, more than one KE_Cj is then written. With respect to authorized mobile unit models, the mobile unit public key KE_MSNi is registered with the communications carrier in advance (step e). The COB device with KE_Cj written therein is assembled into the mobile unit with the mobile unit secret key KD_MSNi, public key KE_MSNi, control programs, etc., written in its EEPROM (step f), and the mobile unit is shipped (step g). When registering the mobile unit, the mobile unit public key KE_MSNi stored in the mobile unit is read out and transmitted to the communications carrier (step h). The communications carrier compares the received KE_MSNi with the previously registered KE_MSNi, and when a match is found, transmits E(KD_Cj, ID), i.e., personal information signature-encrypted with KD_Cj, or E(KE_MSNi, E(DK_Cj, ID) if it is further encrypted with KE_MSNi), and E(KD_Cj, KE_MSNi), i.e., KE_MSNi signature-encrypted with KD_Cj (step i). Then, the commands of item Nos. 8 and 6, containing the received E(KD_Cj, ID) and E(KD_Cj, KE_MSNi), respectively, are entered into the COB device, thus writing the personal information ID and mobile unit public key KE_MSNi into the COB device (step j). To read out the personal information stored in the COB device, the command of item No. 9, containing the KD_MSNi stored in the EEPROM of the mobile unit, is entered.

In the above method of mobile unit registration, the personal information is written into the EEPROM within the COB device, and cannot be read out or written in by directly addressing the EEPROM. This arrangement prevents the personal information stored in the registered mobile unit from being copied to other mobile units having no personal information written therein. When reading out the personal information, the data encrypted with KE_MSNi in the COB device is decrypted by using the corresponding KD_MSNi. Therefore, the personal information cannot be read out correctly unless the mobile unit secret key KD_MSNi, which is known only to the mobile unit manufacturer, is entered. Even if it is attempted to enable readout by determining a KD_MSNi/KE_MSNi pair in a random manner and by illegally writing KE_MSNi, KE_MSNi with a digital signature encrypted with the secret key KD_Cj corresponding to the carrier public key KE_Cj held in the COB device must be entered in order to write KE_MSNi. Further, even if it is attempted to enable the writing of KE_MSNi by determining a KD_Cj/KE_Cj pair in a random manner and by illegally writing KE_Cj, the password and KE_Cj with a digital signature encrypted with the common secret key KD_COB must be entered in order to write KE_Cj. Furthermore, even if it is attempted to illegally write KE_COB by determining a KD_COB/KE_COB pair in a random manner, KE_COB cannot be altered illegally since KE_COB is stored in an unalterable ROM. As a result, the personal information cannot be read out without knowing the KD_MSNi determined by the mobile unit manufacturer. Also, the personal information cannot be written in unless one knows the KD_Cj corresponding to the KE_Cj stored in the COB device. Since KE_Cj cannot be altered arbitrarily, as already explained, it follows that the personal information cannot be written in unless one knows the KD_Cj determined by the communications carrier.

As described above, the personal information cannot be read out or written in without knowing a specific secret key. Besides, even a person who is in a position to know one or the other of the two keys, KD_MSNi and KD_Cj, cannot do both writing and reading unless he knows the other key, so that the personal information written in a mobile unit cannot be copied into other mobile units having no personal information written therein. Furthermore, KE_MSNi of every approved mobile unit model is registered with the communications carrier, and personal information is assigned only to mobile units having the registered KE_MSNi. This arrangement prevents the personal information from being written into mobile units of a model that cannot be connected to or is not permitted to be connected to the communications network.

Since the common secret key KD_COB is common to all carriers concerned, leakage of this key would have a serious effect. Accordingly, a password is entered using the command of item No. 2 prior to the entry of the command of item No. 4 unit, and the password is changed for every lot of COB devices to minimize the effect that would result when KD_COB was leaked out. It will be noted here that there will be no problem even if the COB manufacturer and the mobile unit manufacturer happen to be the same manufacturer.

Figure 5 is a system setup diagram according to the present invention, for explaining the procedure for on-line registration of a mobile unit when a mobile unit purchased at a dealer authorized under contract with the communications carrier is registered via a registration terminal installed at the dealer or when a mobile unit purchased at some other shop is taken to a dealer having a registration terminal to have the unit registered via the registration terminal. The mobile unit 70 and the dealer's terminal 72 are connected by a cable, and the dealer's terminal 72 is connected via a public network 76 to a carrier's terminal 74 installed at the communications carrier. The carrier's terminal 74 is connected on-line or off-line to a customer management system 78 provided for management of subscribers, and via a public network 82 to a credit company's database 80 to run a credit check on the user who applied for registration.

Figure 6 is a block diagram showing the detailed configuration of the dealer's terminal 72 of Fig. 5. The dealer's terminal 72 comprises a CPU 84, a signal processor 86, a RAM 88, an EEPROM 90, a key 92, and a modem 94, interconnected with one another, and connected via the modem 94 to the public network.

The signal processor 86 provides an interface between the CPU 84 and the mobile unit connected through an input/output terminal 102. The EEPROM 90 contains a program for performing conversion between a serial signal to and from the mobile unit and a signal transmitted and received via the modem 94, a control program, and the telephone number of the carrier's terminal 74. The key 92 is used for selection of operations.

The primary function of the dealer's terminal 72 is to perform conversion between a serial signal to and from the mobile unit and a signal transmitted and received via the modem 94, and control of the transmit/receive sequence to and from the carrier's terminal 74 for mobile unit registration is performed primarily by a program contained in the mobile unit. Furthermore, no information whatsoever concerning the encryption/decryption keys is stored in the dealer's terminal 72. In this manner, a high level of security can be maintained. To reduce the cost of the dealer's terminal, the display of the mobile unit is used to display the operating state during registration; further, the key 92 is only for selection of operations, and the numeric keys, etc., provided on the mobile unit are made use of as necessary.

Figure 6 shows an example in which connection is made to a conventional analog network via a modem, but it will be appreciated that the connection may be made to an analog network via a DTMF transmitter and receiver to perform transmission and reception using DTMF (dual tone multi-frequency) signals. Furthermore, connection with an ISDN network or a packet network can also be realized with ease.

Figures 7 and 8 are diagrams for explaining a sequence for a new mobile unit registration in the system setup illustrated in Fig. 5. Referring to Fig. 7, first the dealer's terminal is connected on-line to the carrier's terminal by dialing the communications carrier from the dealer's terminal installed at the dealer (steps a, b). When the controller of the mobile unit is activated from the dealer's terminal (step c), the controller of the mobile unit sends the command of item No. 10 in Table 1 to the COB device to request a random number from the COB device (step d). The COB device then generates a random number, and transfers the random number RDM to the controller of the mobile unit (step e) while, at the same time, storing its value RDM into its RAM. The controller of the mobile unit stores the received random number RDM into its RAM, and at the same time, sends a registration start request message, including the random number, to the carrier's terminal via the dealer's terminal (step f). The carrier's terminal signature-encrypts the received random number RDM with the carrier secret key (KD_CN, and returns the result E(KD_CN, RDM) (step g). The controller of the mobile unit sends the command of item No. 11 in Table 1, containing the E(KD_CN, RDM) just received, the RDM stored in the RAM, and the integer J (J = 1, 2, ...), to the internal COB (step h). The internal COB decrypts E(KD_CN, RDM) with the carrier public key KE_CN stored in its EEPROM at a position specified by the integer J, and determines whether the decrypted result matches the RDM contained in the entered command. If they match, the readout result is rendered OK and the KE_CN is returned to the controller of the mobile unit (step i). If they do not match, the readout result NG is returned. Upon receiving the readout result NG, the controller of the mobile unit updates the value of J to J + 1, and again sends the command of item No. 11 to the internal COB (step h). If KE_CN cannot be read out even when the value of J has reached a predetermined value, this means that the KE_CN for the communications network to which the applicant desires to subscribe is not stored in the COB in the mobile unit; i.e., it is found that the mobile unit that requested registration cannot be used in the communications network to which the applicant desires to subscribe. If KE_CN can be read out, it means that the mobile unit is usable; then, an operation menu is displayed on the display of the mobile unit for selection of operations, prompting the operator to input the credit card number of the applicant and the type of additional service the applicant desires to subscribe to (step j). When these pieces of information are input, the command of item No. 12 in Table 1 is entered three times to request the internal COB for encrypt calculation (step k), as a result of which E(KE_CN, KE_MSNm), i.e., the mobile unit public key KE_MSNm encrypted with the carrier public key KE_CN, E(KD_MSNm, credit card No.), i.e., the credit card No. signature-encrypted with the mobile unit secret key KD_MSNm, and E(KD_MSNm, additional service information), i.e., the additional service information signature-encrypted with KD_MSNm, are received from the internal COB (step l).

Referring next to Fig. 8, the controller of the mobile unit sends a telephone number request message, containing the above data, to the carrier's terminal (step m). The carrier's terminal performs decryption using the carrier secret key KD_CN, obtains KE_MSNm, and checks if the decrypted KE_MSNm matches any one of the previously registered KE_MSNi. If there is no match, the registration is denied. If there is a match, the credit card No. and the additional service information are recovered using the KE_MSNm. The recovered credit card No. is reported to the credit company's database 80 via the public network 82 (Fig. 5) for automatic investigation of the applicant's credit; if the result is OK, an assigned telephone number (DN) is received from the customer management system (step n). The telephone number received from the customer management system is encrypted with the mobile unit public key KE_MSNm and transferred to the controller of the mobile unit (step o). Upon receiving the encrypted telephone number E(KE_MSNm, DN), the controller of the mobile unit sends the command of item No. 12, containing the encrypted telephone number and the mobile unit secret key KD_MSNm, to the internal COB for encrypt calculation (step p), and then, receives the result of the calculations, i.e., the telephone number, which is displayed (step q). if the displayed telephone number is not one that the applicant desires, the process returns to step m. If the displayed telephone number is one that the applicant desires, the controller of the mobile unit sends a personal information request message, containing the telephone number E(KE_CN, DN) encrypted with the carrier public key, to the carrier's terminal (step r). E(KE_CN, DN) is calculated using the command of item No. 12. The carrier's terminal queries the customer management system and receives the personal information assigned from the customer management system (step s). Then, the personal information is signature-encrypted with the carrier secret key KD_CN, and is further encrypted with the mobile unit public key KE_MSNm to produce E(KE_MSNm, E(KD_CN, ID)), which is then transmitted from the carrier's terminal to the controller of the mobile unit along with E(KD_CN, KE_MSNm) which is the mobile unit public key KE_MSNm signature-encrypted with the carrier secret key KD_CN (step t). The controller of the mobile unit enters the command of item No. 6, containing the received E(KD_CN, KE_MSNm), into the internal COB, thus writing KE_MSNm (step u), and then enters the command of item No. 8, containing the received E(KE_MSNm, E(KD_CN, ID)) and the E(KD_CN, RDM) previously received in step g, into the internal COB, thus writing the personal information (step v).

In the above-described on-line registration sequence, every information whose contents need to be kept confidential is encrypted with the recipient's public key prior to transmission to prevent the contents from leaking out. Furthermore, for information that needs to be received only from a designated sender, the information is signature-encrypted with the secret key of the party that the recipient recognizes as the designated sender (the party whose public key is held by the recipient) prior to transmission to the recipient, thus preventing illegal writing by a party disguised as a communications carrier. Furthermore, since a match in random number is checked when writing personal information, if it is attempted to produce a duplicate mobile unit by transferring a message, obtained by intercepting the whole communication between the carrier's terminal and the mobile unit, to a mobile unit having no personal information written therein, the writing is prohibited as the random number RDM that the internal COB generates each time does not match.

When a faulty mobile unit is brought to the dealer and its repair is completed, the personal information is updated in a similar sequence to that described above. This procedure is necessary to prevent anyone from obtaining a duplicate of a legally registered mobile unit; e.g., consider a case in which someone, who has a legally registered mobile unit, deliberately broke another mobile unit having no personal information written therein and requested repair. By updating the personal information, if there is another mobile unit initially registered, the ID stored in that mobile unit no longer matches the ID registered to the communications network so that that other mobile unit can no longer be used. Updating personal information is performed in the sequence shown in Figures 9 and 10.

Updating the contents of additional services is performed in the sequence shown in Figs. 11 and 12 which is similar to the above sequence. Depending on the kind of additional service to be added, it may become necessary to change the ID information (e.g., dial lock, call waiting, etc.); therefore, the ID information is always sent and written in even if there is no change.

Updating the credit card number is also performed in a similar sequence, as shown in Figs. 13 and 14.

Figure 15 is a diagram for explaining a method of mobile unit registration according to another embodiment of the present invention. The same component elements as those shown in Fig. 5 are designated by the same reference numerals, and description of such elements will not be repeated here. In this embodiment, a dealer's terminal 110 and a mobile unit 112 are connected not by a cable but by radio (power-conserving radio) that uses very low power.

Figure 16 is a block diagram showing the configuration of the mobile unit 112 shown in Fig. 15. The same component elements as those shown in Fig. 1 are designated by the same reference numerals.

A power amplifier 114 contained in the transmitter of the radio unit 10 provides a transmitting power which is selectable by an instruction from the CPU 16. During the registration process, the CPU 16 switches the power of the power amplifier 114 to very low power and the frequency of a voltage-controlled oscillator 116 to a frequency capable of transmitting and receiving a predetermined frequency for registration processing. This allows the transmission and reception of signals to and from the dealer's terminal without using a cable. Furthermore, since the power of the power amplifier 114 is switched to very low power, the ID information is prevented from being intercepted with radiowaves leaking outside the housing, and also, consumption of the battery of the mobile unit can be reduced during ID writing.

Figure 17 is a block diagram showing the configuration of the dealer's terminal shown in Fig. 15. The same component elements as those shown in Fig. 6 are designated by the same reference numerals.

In Fig. 17, a CPU 84 is coupled to the mobile unit 112 by power-conserving radio via a radio unit 118 operating on the predetermined frequency for registration processing. During registration, the mobile unit 112 is placed inside the housing of the dealer's terminal 110 for increased security, as will be described later. Consequently, since the keys and display on the mobile unit cannot be used for registration processing, a keypad 120 includes keys, such as numeric keys, necessary for registration processing, in addition to the key for operation selection, and further, a display 122 is added.

Figure 18 is a diagram providing an external view of the dealer's terminal 110. The mobile unit is placed sideways in a drawer 124 provided in one side in such a manner that its antenna is coupled with a flat print antenna 126 formed on an inner surface of the drawer 124. The drawer 124 is then pushed in and locked with a key 128, which turns on the power to the dealer's terminal 110. The registration of the mobile unit, updating of the ID information, changing of additional services, and changing of the credit card number are performed, preferably in accordance with the respective sequences described with reference to Figures 7 to 14. However, if the security of the communication line and the authentication of the carrier and mobile manufacturer are not needed, the steps of encryption, digital signature, etc. may be omitted. Furthermore, the registration procedure may be performed off-line instead of connecting on-line to the carrier's terminal, in which case the modem 94 is not needed. In this case, however, it is required that an expected number of mobile unit registrations at the dealer be predicted and, based on the prediction, a sufficient number of ID information sets be provided in advance from the communications carrier.

In this embodiment, since the dealer's terminal 110 and the mobile unit 112 are connected not by a cable but by power-conserving radio, the mobile unit need not be provided with a connector for cable connection. This allows a further reduction in the size of the mobile unit. Furthermore, by providing a transmitting power selection function within the mobile unit, as previously described, the antenna and transmit/receive circuitry provided for the mobile unit to communicate with the base station can also be used for transmission and reception of signals to and from the dealer's terminal. Also, since the dealer's terminal does not require cables for connection with different mobile unit models, the dealer need not have different ROM writers for different models. Moreover, since no metal contacts are exposed on the mobile unit for connection with a ROM writer, the construction serves to reduce the possibility of the personal information being stolen through such contacts.

Figure 19 is a block diagram showing the configuration of an IC card insertion type mobile unit according to another embodiment of the present invention. The same component elements as those of the ID containing type mobile unit shown in Fig. 1 are designated by the same reference numerals. As compared with the ID containing type mobile unit of Fig. 1 in which the ID information is written in the COB device 22, the IC card insertion type mobile unit of Fig. 19 is enabled to be connected to the communication network when an IC card 130 holding the ID information is inserted into the mobile unit. Therefore, no control programs for registration processing are contained in the EEPROM 20 in the mobile unit.

Figure 20 is a block diagram showing the configuration of the IC card 130. The IC card 130 has a similar configuration to that of the COB device 22 shown in Fig. 2, and the same component elements are designated by the same numerals as those shown in Fig. 2. In the IC card 130, as in the COB device 22, the contents of the EEPROM 36 cannot be read out or written in unless specific commands are given to the CPU 30. The contents of the ROM 34 are written in during the manufacture of the IC card and are not alterable.

The EEPROM 36 contains the carrier public key KE_Cj and mobile unit public key KE_MSNi as well as the personal information 48. Unlike the ID containing type mobile unit, since one IC card can be used for only one communications network, only one KE_Cj is stored; on the other hand, since the mobile unit capable of being connected to the communications network may be available in more than one model, the IC card is designed to be capable of storing more than one KE_MSNi. KE_Cj, KE_MSNi, and personal information are written in when registering the IC card to the communications network. In cases where the IC cards are intended for a particular communications network, it is preferable that each IC card be fabricated with KE_Cj presaved during manufacture before shipment. In this case, it is preferable that KE_Cj be written into the ROM 34 instead of the EEPROM 36; then, the common public key KE_COB and password PWD need not be written into the ROM 34. Details of command accepted by the IC card will be described later.

Figure 21 schematically shows the data stored in the EEPROM 20 of the mobile unit shown in Fig. 19. The data construction is substantially the same as that for the ID containing type mobile unit shown in Fig. 3; differences are that the personal data write flag 58 of Fig. 3 is omitted and that the control program 54 does not contain programs for registration processing as previously described.

Figure 22 is a diagram for explaining the outline of a method of IC card registration according to the present invention. A load module containing password PWD, common public key KE_COB and control program data is supplied from the communications carrier to the IC card manufacturer responsible for the manufacture of the IC card (step a), where the data are written into the ROM of the IC card (step b) which is then shipped. The process up to this point is the same as the process up to the shipment of the COB device for the ID containing type mobile unit previously described with reference to Fig. 4. When the module unit that the mobile unit manufacturer manufactures is authorized by the communications carrier, KE_MSNi for that model of mobile unit is registered with the communications carrier (step j). In registering the IC card, first the passwords PWD and E(KD_COB, KE_Cj) are received from the communications carrier (step c), and KE_Cj is written into the IC card (step d). If KE_Cj is already written in the IC card at the IC card manufacturer before shipment, as previously described, the above process is not necessary; the elimination of this process is desirable from the standpoint of avoiding the problem of leakage of the password PWD. Next, E(KD_Cj, ID), the personal information ID signature-encrypted with KD_Cj, and E(KD_Cj, KE_MSNi), the registered KE_MSNi signature-encrypted with KD_Cj, are received from the communications carrier (step e), and the personal ID and KE_MSNi are written into the EEPROM contained in the IC card (step f). On the other hand, the mobile unit with KD_MSNi and KE_MSNi written in its EEPROM is shipped from the mobile unit manufacturer (step g). When the IC card with ID written therein is inserted into the mobile unit (step h), the ID can be read by the mobile unit by using KD_MSNi. When there are a plurality of mobile unit models authorized for use in the communications network to which the IC card is registered, KE_MSNi's for all such models are supplied from the communications carrier and stored on the IC card.

Like the ID containing type mobile unit described with reference to Fig. 4, in the above IC card registration method also, the EEPROM of the IC card cannot be read from or written to by directly addressing it, and therefore, simply copying the IC card is not possible. To read out the personal information, one has to know the mobile unit secret key KD_MSNi, and to write in, one has to know the carrier secret key KD_Cj. If one knows one or other of the secret keys, he cannot do both reading and writing unless he knows the other; therefore, copying is not possible. Furthermore, the IC card contains KE_MSNi for all models authorized for use in the communications network that provides the service; if the IC card is inserted into a mobile unit that does not have KD_MSNi corresponding to the KE_MSNi held in the IC card, the ID cannot be read by such a mobile unit. This prevents unauthorized mobile units from radiating undesired radiowaves.

Figure 23 is a block diagram showing the configuration of an IC card registration terminal used for on-line registration of the IC card.

This IC card registration terminal is, in fact, identical in construction to the ID containing type mobile unit described with reference to Figs. 1 to 3, except that the COB device 22, radio unit 10, speaker 12, microphone 14 and control programs required for operation as a mobile unit are removed, while the functions of the dealer's terminal described with reference to Fig. 6 and COB devices supporting a plurality of communications carriers are added. Preferably, this IC card registration terminal is registered with each communications carrier and given unique personal information ID_AN, like the ID containing type mobile unit. This registration terminal has a registration terminal secret key KD_AN and public key KE_AN corresponding to the mobile unit secret key KD_MSNi and public key KE_MSNi, respectively. As in the case of the mobile unit, the KD_AN/KE_AN pair is determined for each model of IC card registration terminal.

As shown in Fig. 23, the IC card registration terminal 140 has a CPU 142 to which are connected a RAM 144, an EEPROM 146, a keypad 168, a display 170, a plurality of COB devices 172, and a modem 174. The COB devices are provided one for each of the communications networks to which the IC card registration terminal can register, one of them being selected by means of a selector switch 176. Figure 24 shows an external view of the IC card registration terminal.

Figure 25 is a block diagram showing the configuration of the COB device 172. Each COB device 172 contained in the IC card registration terminal, shown in Fig. 25, has a similar configuration to that of the COB device 22 contained in the ID containing type mobile unit, shown in Fig. 2, and the IC card shown in Fig. 20. The EEPROM 36 of the COB device 172 stores therein personal information of the IC card registration terminal, which includes the number of the dealer at which the IC card registration terminal is installed, an authentication key of the IC card registration terminal, etc. In addition to KE_Cj, the registration terminal public key KE_AN and signature data E(KD_COB, KE_Cj), which is KE_Cj signature-encrypted with KD_COB, are stored.

The contents of the ROM 34 of the COB device 172 are written in during the manufacture of the COB device 172, and are not alterable. Of the contents of the EEPROM 36, KE_Cj and E(KD_COB, KE_Cj) are written in during the manufacture of the IC card registration terminal, and after the IC card registration terminal is delivered to the dealer, KE_AN and the personal information are written in for the registration of the IC card registration terminal with the communications carrier before starting the IC card registration service.

Figure 26 schematically shows the data stored in the EEPROM 146 of the IC card registration terminal 140 shown in Fig. 23. As in the EEPROM 20 of the ID containing type mobile unit shown in Fig. 3, the control program 54, fixed patterns 56, and ID write flag 58 are stored, and instead of the KD_MSNi/KE_MSNi pair, the KD_AN/KE_AN pair is stored. These are written in during the manufacture of the IC card registration terminal; of these data, the ID write flag is updated when the personal information has been written in.

Figure 27 is a diagram for explaining an outline of the process from the manufacture to the registration of the IC card registration terminal. The process shown is substantially the same as that for the ID containing type mobile unit registration described with reference to Fig. 4, but the KD_MSNi/KE_MSNi pair is replaced by the KD_AN/KE_AN pair. Furthermore, the signature data E(KD_COB, KE_Cj) received from the communications carrier in step c is not only decrypted with KE_COB and written in KE_Cj, but also written in the encrypted form into the COB device in step d. This is necessary because data signature-encrypted with KD_Cj needs to be entered when writing KE_Cj into the IC card during the IC card registration process, but this is not necessary when the IC card is shipped from the IC card manufacturer with KE_Cj already written therein.

As in the case of the ID containing type mobile unit, it is essential to know the carrier secret key KD_Cj if it is desired to write the terminal's personal information ID_AN into the COB device contained in the IC card registration terminal, and it is essential to know the registration terminal's secret key KD_AN if it is desired to read out ID_AN. Accordingly, making a duplicate of the IC card registration terminal is virtually impossible.

Table 2 is a listing of commands that are accepted by the COB device 172 contained in the IC card registration terminal 140. <tables id="tabl0002" num="0002"><img file="EP0652681A2_D0006.tif" /></tables>

The commands are substantially the same as those shown in Table 1 for the COB device 22 of the ID containing type mobile unit. The differences are that the commands for writing and reading the signature data E(KD_COB, KE_Cj) are added as commands of item Nos. 3 and 5, that KD_MSNi and KE_MSNi are replaced by KD_AN and KE_AN in commands of item Nos. 6, 8, and 9, and that KE_Cj is not input with commands of item Nos. 6 and 8. The command of item No. 3 is entered in supervisor mode. KE_Cj is not input with commands of item Nos. 6 and 8 because no selection is necessary since only one KE_Cj is stored in the COB device 172. However, for standardization of the process, KE_Cj may be input for comparison with the stored KE_Cj.

Figure 28 is a diagram showing a setup in which the IC card registration terminal delivered to the dealer is registered with the communications carrier to effect the IC card registration service before the dealer starts the registration service. In Fig. 28, the telephone number of the carrier's terminal 74 installed at the communications carrier is dialed from the IC card registration terminal delivered to the dealer, whereupon the IC card registration terminal 140 is connected to the carrier's terminal 74 via a public network 72 and a registration sequence for the registration of the IC card registration terminal is initiated.

Figures 29 and 30 show the registration sequence for registering the IC card registration terminal with the communications carrier. Registration with any additional communications carrier is performed in the same sequence.

In Fig. 29, first the COB device selector switch 176 (see Figs. 23 and 24) is set to select the COB device holding the public key KE_CN of the desired carrier CN, and the telephone number of that carrier's terminal is dialed to request a connection. When the carrier's terminal responds, the command of item No. 10 in Table 2 is entered into the internal COB device (step b), and the random number RDM is received (step c). At this time, the value of RDM is also stored into the RAM of the COB device. Upon receiving the random number RDM, the IC card registration terminal stores the same into its RAM, and at the same time, sends a registration start request message, containing the random number RDM, to the carrier's terminal (step d). Upon receiving the random number RDM, the carrier's terminal signature-encrypts the received random number RDM with the carrier secret key KD_CN, and returns the result E(KD_CN, RDM) (step e). Upon receiving E(KD_CN, RDM), the IC card registration terminal sends the command of item No. 11 in Table 2, containing the received E(KD_CN, RDM), the RDM stored in its RAM, and the integer J (J=1), to the internal COB (step f) to read out the carrier public key KE_CN (step g). Next, a message is displayed on the display prompting the operator to input the dealer number; when the dealer number is entered (step h), the command of item No. 12 in Table 2 is entered twice to request the internal COB for encrypt calculation (step i), as a result of which E(KE_CN, KE_AN), the registration terminal public key KE_AN encrypted with the carrier public key KE_CN, and E(KE_CN, dealer number), the dealer number encrypted with KE_CN, are received (step j).

Referring next to Fig. 30, the registration terminal sends a registration request message, containing the above data, to the carrier's terminal (step k). The carrier's terminal decrypts the data using the carrier secret key KD_CN, to derive the dealer number and KE_AN, which are then compared with the dealer numbers and KE_AN's stored in the carrier's terminal for a match (step l). If a match is found, E(KD_CN, KE_AN), KE_AN signature-encrypted with KD_CN, and E(KE_AN, E(KD_CN, ID_AN)), the registration terminal ID assigned to the registration terminal signature-encrypted with KD_CN with the result further encrypted with KE_AN, are sent back (step m). Upon receiving these data, the registration terminal writes KE_AN into the internal COB device by using the command of item No. 6 (step n), and ID_AN into the same by using the command of item No. 8 (step o).

Figure 31 is a diagram showing a setup in which the IC card 130 is registered with the communications carrier by using the IC card registration terminal 140. The same reference numerals are appended to the same component elements as those shown in Fig. 5 that illustrates the registration setup for the ID containing type mobile unit. When registering the IC card by connecting the IC card registration terminal 140 to the communications carrier via a public network 76, the IC card registration terminal 140 needs to be authenticated by using the ID_AN stored in its internal COB.

Figure 32 shows a sequence for the authentication of the IC card registration terminal. First, the switch 176 is operated to select the COB device corresponding to the communications carrier to which a connection is to be set up, and the telephone number of the carrier's terminal is dialed (step a). When the line is connected, the random number RDM is read out by using the command of item No. 10 (step b), and is transmitted to the carrier's terminal (step c). The carrier's terminal signature-encrypts RDM with KD_CN and returns the result E(KD_CN, RDM) (step d). The IC card registration terminal enters the command of item No. 11, containing the E(KD_CN, RDM) received from the carrier's terminal, the integer J (J=1), and RDM, into the internal COB to read out KE_CN (step e). Next, the KD_AN stored in the EEPROM 146 is read out, and the command of item No. 9, containing the same, is entered to read out ID_AN (step f). Then, the command of item No. 12 is entered twice into the internal COB, to calculate E(KE_CN, KE_AN) and E(KE_CN, ID_AN) (step g), which are then transmitted to the carrier's terminal (step h). Using KD_CN, the carrier's terminal decrypts the data to recover KE_AN and ID_AN, and if they are correct, sends an IC card write permit notice to the IC card registration terminal (step i), thereby displaying an operation permit message on the display 170.

Table 3 shows a listing of commands that the IC card 130 accepts. <tables id="tabl0003" num="0003"><img file="EP0652681A2_D0007.tif" /></tables>

The commands are substantially the same as those shown in Table 1 for the internal COB device of the ID containing type mobile unit. The differences are that the command for erasing KE_MSNi is added as command of item No. 7, and that with the command of item No. 8, KD_AN is input, instead of KD_MSNi, for ID information write; inputting KD_MSNi for read is the same. Since only one KE_Cj is stored, there is no need to input KE_Cj with the commands of item Nos. 6 and 7. On the other hand, since there is a possibility that more than one KE_MSNi may be stored, KE_MSNi is input with the command of item No. 9 to specify one KE_MSNi.

Figures 33 to 35 show a processing sequence for IC card registration. The portion enclosed with symbol * is a sequence for writing the carrier public key KE_CN into an IC card that does not contain KE_CN. This particular portion of the processing sequence is not necessary for IC cards shipped from the IC card manufacturer with KE_CN already written therein. The other portions of the processing sequence are substantially the same as the processing sequence for ID containing type mobile unit registration described with reference to Figs. 7 and 8. The differences are that the KE_CN readout process is finished in a single step since only one KE_CN is stored, that KE_AN is used, instead of KE_MSNi, when making a request to the carrier's terminal and when performing encryption at the carrier's terminal, and that there is a possibility that more than one KE_MSNi may be sent from the carrier's terminal.

Figures 36 and 38 show a sequence for updating the personal information assigned to the subscriber. When, e.g., an IC card is broken and replacement of the IC card is requested, the illustrated sequence is carried out to update the personal information. As in the case of the ID containing type mobile unit, this information updating is necessary to prevent anyone from obtaining a duplicate of a legally registered IC card; e.g., consider a case in which someone, who has a legally registered IC card, deliberately broke another IC card having no ID written therein and requested the dealer for replacement of the IC card. By updating the personal information when replacing the IC card, if there exists an IC card initially registered, the ID held in that IC card no longer matches the ID registered to the communications network, so that such an IC card can no longer be used.

Figures 39 to 41 show a sequence for updating the contents of additional services. Depending on the contents of additional services to be added, it may become necessary to change the ID information; therefore, the ID information is always written even when there is no need to change it. Figures 42 to 44 show a sequence for changing the credit card number.

According to the IC card registration method described above, the EEPROM 36 of the IC card 130 stores mobile unit public keys, KE_MSNi, for all IC card insertion type mobile units authorized for use in the communications network that the IC card holder subscribes to, i.e., for all mobile unit models that can perform communication when the IC card is inserted, and only the mobile units whose EEPROM 20 contains KD_MSNi corresponding to one of these public keys can read ID from the IC card. Therefore, after the IC card has been registered with the communications network, if any additional mobile unit model is approved for use, the KE_MSNi of that mobile unit model needs to be written into the IC card if the IC card is to be used with that additional mobile unit. For this purpose, the user needs to have the communications carrier or dealer write the KE_MSNi into his IC card, which is cumbersome.

Figure 45 schematically shows the data stored in an EEPROM 20' of an IC card insertion type mobile unit according to another embodiment of the invention that overcomes the above disadvantage. This EEPROM 20' stores, in addition to KD_MSNi, KE_MSNi, etc., a KE_Cj/E(KD_Cj, KE_MSNi) pair as an evidence of authorization by a communications carrier Cj, the latter of the pair being KE_MSNi signature-encrypted with the carrier secret key KD_Cj of the communications carrier concerned. KE_Cj is used to select one E(KD_Cj, KE_MSNi) when more than one E(KD_Cj, KE_MSNi) is stored, and is not necessary when there is no possibility that more than one E(KD_Cj, KE_MSNi) will be stored. To prevent abuse, it is desirable that these data also be stored in a shuffled form, as in KD_MSNi and KE_MSNi, so that they are unrecognizable by simple comparison.

Since the mobile unit holds KE_MSNi signature-encrypted with the carrier's KD_Cj, when an IC card authorized for use but with KE_MSNi not written therein is inserted into the mobile unit, the IC card can be made usable with the mobile unit by entering the command of item No. 6 in Table 3, containing the above data, and thereby writing KE_MSNi into the IC card. In such a case, KE_MSNi need not necessarily be stored during the registration of the IC card.

Figure 46 shows an example of a sequence starting from the time when the IC card is inserted and power is turned on to the mobile unit, until the personal information is read out to set the unit ready for communication. In Fig. 46, when the command of item No. 9, containing KD_MSNi and KE_MSNi, is entered after power on (step a), if the read result is OK and ID is read out, sleep mode is instructed to the IC card (step b), and the normal processing starts. If the read result is NG, one of the signature data E(KD_Cj, KE_MSNi) is read out (step c), and is input along with J (J=1) and KE_MSNi as the command of item No. 11, to the IC card, to read out KE_Cj (step d). In the IC card, the input signature data E(KD_Cj, KE_MSNi) is decrypted with the KE_Cj designated by the integer J and contained in the IC card; if KE_MSNi cannot be decrypted, the read result NG is returned, upon which the process returns to step c to read the next signature data which is input to the IC card as the command of item No. 11. If no signature data held in the mobile unit can be decrypted with the KE_Cj contained in the IC card, then it is decided that the mobile unit cannot be used. If the entered signature data is successfully decrypted using the KE_Cj contained in the IC card, the result OK is returned, upon which the command of item No. 6, containing this signature data, is entered to the IC card to store KE_MSNi into the IC card (step e). The ID is now ready to read out, so that the command of item No. 9, containing KE_MSNi and KD_MSNi, is entered into the IC card to read out the ID (step f).

Figure 47 is another example of the sequence up to the step where the ID is read out. In the sequence of Fig. 47, KE_MSNi is immediately registered to read out the ID without first determining whether the ID can be read out. If KE_MSNi is already stored in the IC card when a write is attempted, the write step is skipped. While the sequence of Fig. 47 is simpler in processing than the sequence of Fig. 46, the sequence always requires a certain length of time from the moment power is turned on, until the unit is set ready for communication.

In alternative embodiment, no KE_MSNi is written into the IC card, but the IC card control program is modified so that ID can be read out by entering KD_MSNi and E(KD_Cj, KE_MSNi) as the command of item No. 9 in Table 3, as shown in Table 4. <tables id="tabl0004" num="0004"><table frame="all"><tgroup cols="5" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="31.50mm" /><colspec colnum="2" colname="col2" colwidth="31.50mm" /><colspec colnum="3" colname="col3" colwidth="31.50mm" /><colspec colnum="4" colname="col4" colwidth="31.50mm" /><colspec colnum="5" colname="col5" colwidth="31.50mm" /><tbody valign="top"><row rowsep="1"><entry namest="col1" nameend="col1" align="right">9</entry><entry namest="col2" nameend="col2" align="left">ID information read</entry><entry namest="col3" nameend="col3" align="left">E(KD_Cj, KE_MSNi), KD_MSNi</entry><entry namest="col4" nameend="col4" align="left">ID Read result ((OK/NG)</entry><entry namest="col5" nameend="col5" align="left">KE_Cj is already registered</entry></row></tbody></tgroup></table></tables>

When the command shown in Table 4 is entered, the CPU 30 of the IC card decrypts E(KD_Cj, KE_MSNi) with the stored KE_Cj to recover KE_MSNi, then encrypts the stored ID with the recovered KE_MSNi and further encrypts the encrypted result with the entered KD_MSNi before output. In this case also, the processing in steps c, d, etc. shown in Fig. 46 should be carried out to determine which signature data matches the KE_Cj contained in the IC card, or, an ID readout operation should be repeated using respective signature data until an ID having a matching fixed pattern is read out.

In the IC card registration methods described above, depending on the model of the mobile unit in which the IC card is inserted, all the additional services that the user has subscribed to and that are registered on the IC card may not be available for use with the mobile unit even when communication is possible. Therefore, information concerning the additional services that can be used is stored in the EEPROM 20 (Fig. 21) or 20' (Fig. 45) of the mobile unit, and after the ID information is read out, the information stored in the EEPROM is compared with the information, contained in the ID information, concerning the additional services that the user has subscribed to; if there is any service that the user has subscribed to but cannot be used with the mobile unit, a message, such as "So and so service cannot be used with this mobile unit", is displayed on the display of the mobile unit. This enables the user to know, upon inserting his IC card into the mobile unit, if there is any service that cannot be used.

The commands that are accepted by the internal COB device of the ID containing type mobile unit, the commands that are accepted by the internal COB device of the IC card registration terminal, and the commands that are accepted by the IC card have been described with reference to Table 1, Table 2, and Table 3 (and Table 4), respectively. If a control program is created that can accept all of these commands, such a program can be used common to them. In this case, KE_Cj, which was not input with the command of item No. 6 for the IC card in the previous example, is also input to standardize the process.

The signature data E(KD_COB, KE_Cj) that the communications carrier delivers to the mobile unit manufacturer and the IC card registration terminal manufacturer for writing KE_Cj into the COB device and the IC card, should preferably be delivered in the following manner to prevent the occurrence of errors. First, using the load module received from the communications carrier, a COB device is fabricated which is capable of accepting at least the commands of item Nos. 3 and 5 in Table 2, and a COB writer incorporating the COB device is built. Then, the COB writer is taken to the communications carrier to have the signature data E(KD_COB, KE_Cj) written therein by using the command of item No. 3. Using this COB writer, the manufacturer writes KE_Cj and E(KD_COB, KE_Cj) into the newly manufactured COB devices.

As described above, according to the present invention, the ID containing type mobile unit and the IC card used with an IC card insertion type mobile unit can be prevented from being illegally copied.