JPH0793664B2 - Charged terminal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a charged terminal that performs a charging process in a mobile terminal such as a personal telephone.

[Conventional technology]

In the conventional fixed or semi-fixed type telephone, since there was a billing facility on the call route, billing was easy.
However, unlike mobile phones, it is difficult to charge for mobile phones. That is, since the mobile telephone moves all over the country, the place where the charges for each telephone are held may be far away from the call route.

[Problems to be solved by the invention]

In a mobile telephone, if the call charges are notified to the above-mentioned charge holders, there arises a problem that the total communication amount increases and the communication becomes complicated.

[Means for solving problems]

The charged terminal of the present invention stores a cryptographic key that is shared in advance with a base station that provides a pay service or mediates a pay service.
First identifier conversion means and second identifier conversion means for converting an identifier for identifying a connection request for the service based on a rule shared in advance with the base station, and a total of charges for services already received A storage unit that stores the amount (CH) and the upper limit value (CR) of the accumulated amount, an update unit that updates the accumulated amount (CH) of the charge, and an encryption unit that performs encryption and decryption using the encryption key. And a communication unit that communicates with the base station, first, when receiving the service, sends a connection request to the base station via the communication unit, and then the base station via the communication unit. Receives the identifier (RN) from the identifier, the accumulated amount (CH) and the upper limit (CR) of the charge are encrypted by the encryption means, and then transmitted to the base station, and the communication means after the end of the service. Via the base station The total amount of encrypted charges after adding the charges for the newly received service and the identifier after being converted from
H) is received, and the result of decrypting the converted and encrypted identifier in the encryption means is compared with the result of converting the previously received identifier (RN) in the first identifier conversion means, If the comparison does not match, the same operation is repeated until a request for retransmission is made to the base station via the communication means, and if the comparison matches, the update means cumulative charge (CH) To update the identifier (R
N) is sent to the base station via the communication means after the result of applying the second identifier converting means and the fact that the processing has been normally completed are encrypted by the encrypting means,
When the base station requests a retransmission, the contents of the transmission are retransmitted.

[Action]

FIG. 2 is a diagram showing the operation and principle of the present invention. Hereinafter, the charged terminal is a personal phone carried by an individual, and the service is a call. The configuration of the entire system is shown in FIG.
The public telephone network 341 is used, but it is not limited to this. Broken lines between the personal phones 301, 302, 303, 304 and the base stations 311, 312, 313 indicate wireless communication paths. Personal phone (below
Telephone communication is performed between 301, 302, 303, 304 and home telephones 321, 322. A subscriber information center (hereinafter, simply abbreviated as center) 331 has subscriber information files. A base station (hereinafter referred to as BS) corresponds to a service provider.

In FIG. 2, 201 denotes the processing on the personal telephone side, 202
Indicates the processing of the base station. Hereinafter, ~ is shown in Fig. 2 ~.
It corresponds to. When PT makes a connection request, the base station generates a random number RN and sends it to PT. PT remembers the total CH for this month's telephone usage charges and CR for the deposit, but when receiving RN, RN
And CH and CR are encrypted with a predetermined secret key k and sent to BS. E for encrypted RN, CH, CR
It is written as _k (RN, CH, CR). The security deposit CR is deposited by the subscriber at the time of subscription and is used when the telephone charge is not paid. BS also stores k in advance. The BS decrypts the received E _k (RN, CH, CR), and if the RN does not match the RN at the time of occurrence, the CH or CR cannot be trusted and the connection request is cut off. Connect if correct. If a call is made, the call charge will be added to the CH during that time. CH> CR
The call is disconnected at the time of or when the call ends.
RN1 bit-inverted a predetermined part of RN
And CH are encrypted with k and sent to PT. PT decrypts it,
If RN1 is correct, the received CH is stored as a new telephone usage charge total. RN2 and ANS (information indicating whether or not RN1 was correct) in which a predetermined part of RN is bit-inverted are encrypted and sent to BS. BS decrypts it, and if RN2 is correct and ANS is positive, it ends.
If it is not correct, perform recovery processing. Recovery process, for example, return to the figure and send until CH can communicate to PT correctly,
This is a process of notifying to the subscriber information center on the network side when it fails after a certain number of times or when the reply from PT does not come within a certain time.

The PT connects to a nearby BS, but any BS can charge if the secret key k is held by all BSs. Further, it is not necessary to make an inquiry to the subscriber information center for each communication. Therefore, the problems of the conventional method can be solved. In this case, the PT is configured so that even subscribers cannot access CH, CR, and k.

〔Example〕

FIG. 1 (a) is a block diagram showing an embodiment of the charged terminal according to the present invention. In the figure, a voice circuit 104 converts voice and electrical signals. The billing circuit 106 performs billing processing such as generation of billing information. Control circuit 105
Controls by generating or receiving control information such as call setting. Also, the call is disconnected at the request of the charging circuit 106. The multiplexing / demultiplexing circuit 103 multiplexes the control information from the control circuit 105 and the audio signal from the audio circuit 104 and sends them to the transceiver 102, and conversely demultiplexes the signal from the transceiver 102 to control the audio circuit 104, Send to circuit 105. The antenna 101 receives the radio wave from the BS and sends it to the transceiver 102, and conversely sends the signal from the transceiver 102 to the radio wave and sends it to the BS.

FIG. 1B is a block diagram showing an example of the charging circuit 106. The interface circuit 111 interfaces with the control circuit 105, and the encryption / decryption circuit 114 performs encryption and decryption with the key k. The microprocessor 113 controls the interface circuit 111 and the encryption / decryption circuit 114, and inputs / outputs data to / from the memory 112. Specifically, it operates according to the flowchart shown in FIG. Memory 11
The reference numeral 2 includes a work area as well as a program for the microprocessor 113, storage of keys k and the like.

FIG. 4 is a flow chart showing the work to be executed by the microprocessor 113. First, when a call is made (step 401) and a connection request (step 402) is issued, a random number RN reception waiting state (step 403) is entered. Receive RN (step 404)
After that, the RN, CH, and CR are encrypted by the encryption / decryption circuit 114 (step 405), and the result is transmitted to the BS (step 406).
Then, the call mode (step 407) is entered. Disconnect the call when the call ends or the disconnect request from BS (step
Then, it waits for E _k (RN1, CH) to be sent from the BS for post-processing (step 409). When E _k (RN1, CH) is received (step 410), it is decrypted by k (step 411),
Check if RN1 is the inverse of some pre-determined bits of the previously received RN (step 41
2) If so, change the CH to the received CH (step 413) and the parameter ANS indicating the state of communication termination.
Is set as ACK indicating normal termination (step 414). As a result of checking in step 412, if RN1 is not the inversion of some of the predetermined bits of the previously received RN, the value of ANS is set to NAK indicating an abnormal termination (step 415). Next, RN2 is created by inverting a part of the predetermined bits of RN (step 416), and RN2 and ANS
Is encrypted with k (step 417) and sent to BS (step 41)
8) and ends (step 419).

The charging circuit 106 needs to be inaccessible to the subscriber or the user of the PT, and may be integrated into one chip, for example. It is necessary to write the terminal number or the amount of guarantee on the chip. For this, for example, there is a method of mounting the chip written in the subscriber information center at the time of subscription. You can also use an IC card. For payment at the end of the month, send the CH to the subscriber information center instead of the BS, and the center may debit the bank.

In this embodiment, encryption / decryption can be performed by a microprocessor. If the guarantee amount CR is a fixed amount, it is not necessary to notify BS to each PT. Alternatively, the PT may store the balance CS for CR instead of CH and reduce the CS when calling. It is desirable to replace the key k from time to time because it is less secure when used for a long time. In the future, the key to be used can be set in advance and stored. Also, divide all PTs into several groups, set a key for each group (denoted as group key),
The BS can store all group keys and use them as needed.

Random numbers RN, RN1, and RN2 are used to prevent unauthorized retransmission in addition to tampering and error detection. Unauthorized retransmission is a method of storing a previous message and sending it later. It is possible to prevent these without using random numbers. For example, in Figure 2,
, The PT simply uses the time information TM to generate E _k (TM, C
If H, CR) is sent instead of E _k (RN, CH, CR), BS can decrypt it and if TM is close to the time, it can be determined that there is no injustice. The same applies to the RN1 and RN2 parts.

Although k is always used as the encryption / decryption key, a random number RN can be used as the key. In this case, first BS to PT
Encrypt with k when sending RN. Then, RN is used for all subsequent encryption, and tampering and error detection can be realized by making information redundant. That is, if the redundancy does not occur correctly when decrypted on the receiving side, it is determined to be fraudulent.

〔The invention's effect〕

As described in detail above, according to the present invention, the base station can perform the charging process, not the subscriber information center.
Billing can be performed with almost no increase in processing and communication volume on the network side.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram for showing the action and operation principle of the present invention, FIG. 3 is a configuration diagram of a system example to which the present invention is applied, and FIG. 3 is an execution flow chart of the microprocessor in FIG. 1. 101 ... antenna, 102 ... transceiver, 103 ... multiplexing / separating circuit, 104 ... voice circuit, 105 ... control circuit, 106 ... billing circuit, 111 ... interface circuit, 11
2 ... memory, 113 ... microprocessor, 114 ... encryption / decryption circuit, 201 ... terminal-related billing processing, 202
…… Base station side billing process, 301, 302, 303, 304…
… Personal terminals, 311,312,313 …… Base stations, 321,322…
Home telephone, 331 Subscriber information center, 341 Public telephone network, 401 Call step, 402 Connection request step, 403 Response waiting step, 404 RN receiving step,
405 ... encryption step, 406 ... transmission step, 407 ...
… Call step, 408 …… Call disconnection step, 409 …… Response waiting step, 410 …… E _k (RN1, CH) reception step, 411
...... Decryption step, 412 ...... RN1 correctness determination step, 413 ...... CN update step, 414 …… ANS value set to ACK, 415 …… ANS value set to NAK , 416 ... RN2 creation step, 417 ... encryption step, 418 ... transmission step, 419 ... end step.

Claims (1)

[Claims] 1. A storage unit for storing an encryption key previously shared with a base station which provides a pay service or mediates the provision of a pay service, and a connection request for the service is identified. First identifier conversion means and second identifier conversion means for converting an identifier based on a rule shared in advance with the base station, a cumulative amount of charges for services already received, and an upper limit value of the cumulative amount. The storage device includes a storage unit for storing, an update unit for updating the accumulated amount of the charge, an encryption unit for performing encryption and decryption using the encryption key, and a communication unit for communicating with the base station. When receiving a service, a connection request is sent to the base station via the communication means, and then an identifier is received from the base station via the communication means, and the accumulated amount of the identifier and the charge and The upper limit value is encrypted by the encryption means and transmitted to the base station, and after the service is completed, the identifier after being converted from the base station via the communication means and encrypted and the newly received service Is received and the accumulated total of the encrypted charges is received, and the result of decrypting the converted and encrypted identifier by the encryption means and the previously received identifier are converted into the first identifier conversion. If the comparison does not match, the same operation is repeated until a request is made to the base station for retransmission through the communication means, and the same operation is repeated. After updating the cumulative amount of charges by the updating means and applying the second identifier converting means to the identifier and the fact that the processing has been normally completed, the encrypting means encrypts the communication means and then the communication means The charging terminal sends, when there is a retransmission request from the base station, characterized in that retransmits the contents with said transmission to the base station by.