JPH0793665B2 - Billing device - Google Patents

Description

The present invention relates to a charging device for charging a mobile terminal such as a personal telephone.

[Conventional technology]

In the conventional fixed type 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]

A billing device of the present invention includes a storage unit that stores an encryption key shared in advance with a terminal that intends to use a pay service, an identifier generation unit that generates an identifier for identifying a connection request from the terminal, The identifier, first identifier conversion means and second identifier conversion means for converting based on a rule shared in advance with the base station, encryption means for performing encryption and decryption using the encryption key, and Communication means for communicating with the terminal, and service control means for starting or ending the service to the terminal,
An abnormality notification means for notifying the occurrence of an abnormal situation to the outside is provided, and a connection request is received from the terminal via the communication means,
An identifier (RN) is generated by the identifier generation means and transmitted to the terminal via the communication means, and then the identifier encrypted from the terminal via the communication means and a charge already received at the terminal Cumulative amount of service charges (CH)
And the upper limit value (CR) of the accumulated amount are received, they are decrypted by the encryption means, and if the decrypted identifier does not match the previously transmitted identifier (RN), communication with the terminal is performed. When the processing is completed and coincides, the service control means starts the service to the terminal and the charge of the service is set to the cumulative amount (CH), and the cumulative amount (CH) is set.
Exceeds the upper limit (CR) or there is a service termination request from the terminal, the service is terminated by the service control means, and then the identifier (RN) is converted by the first identifier conversion means. The result and the accumulated amount (CH) value are encrypted by the encryption means and transmitted to the terminal through the communication means, and when there is a retransmission request from the terminal, the transmission content is retransmitted, When the encrypted identifier after conversion and the notification that the processing has been normally completed are received from the terminal, the converted identifier and the notification are decrypted by the encryption means, and the converted identifier and The result of applying the second identifier conversion means to the identifier (RN) is compared, and if the results match, the process ends, and if the comparison does not match, the terminal is requested to retransmit and the comparison is performed. Until they match Again, if the comparison is no response from a certain time after the terminal or repeat a certain number of times and notifies the occurrence of the abnormality by the abnormality notification means to the outside.

[Action]

FIG. 2 is a diagram showing the operation and principle of the present invention. Hereinafter, the terminal is a personal phone carried by an individual, and the service is a call. An outline of the entire system is shown in FIG. I use a public phone 341, but it is not limited to this. Base station 311,31
Wireless communication is performed between the 2,313 and the personal phones 301, 302, 303, 304. Home telephone 321,322 and personal telephone 301,302,303,3
04 Telephone communication between each other. Subscriber Information Center 331
Holds subscriber information. In FIG. 2, 201 indicates processing on the telephone side, and 202 indicates processing on the base station. Less than,~
Corresponds to ~ in FIG. When a personal telephone (hereinafter referred to as PT) makes a connection request, a base station (hereinafter referred to as BS) generates a random number RN and sends it to PT. PT remembers the total CH for this month's telephone charges and the deposit CR, but when RN is received, RN, CH, CR are the secret key k
Encrypt with and send to BS. In the figure, the encrypted RN, CH, CR
It is written as E _k (RN, CH, CR). The deposit 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. BS received E _k
Decrypt (RN, CH, CR), and if the RN does not match the RN at the time of occurrence, the CH or CR cannot be trusted, so the connection request is disconnected. Connect if correct. If a call is made, the call charge will be added to the CH during that time. When the channel becomes CH> CR or when the call ends, the call is disconnected and RN1 and CH are bit-inverted by bit-reversing a predetermined part of RN.
Encrypted with and sent to PT. The PT decrypts it and, if RN1 is correct, stores the received CH as a new telephone usage charge total. RN2 and ANS, which are bit-reversed bits of a predetermined part of RN (information indicating whether RN1 was correct)
Is encrypted and sent to BS. The BS decrypts it and terminates if RN2 is correct and ANS is affirmative, otherwise recovery processing is performed. For example, in the recovery process, return to the figure and send until the CH can communicate to the PT correctly, and if it fails after a certain number of times or if the reply from the PT does not arrive within a certain time, notify the subscriber information center on the network side. That is the process.

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 call. 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 charging device of the present invention. 101 and 105 are reception antennas and transmission antennas, respectively, for communication with the PT. 102 and 106 are receivers,
It is a transmitter. Line Supervision 104
Is to convert a call from each PT into a form suitable for a public line, or vice versa. Receive antenna 101, transmit antenna 1
05, receiver 102, transmitter 106, line supervision frame 104 constitutes an existing personal telephone system. Demultiplexing circuits and multiplexing circuits 103 and 107 separate the charging signal to the charging circuit 108, and conversely multiplex the charging signal from the charging circuit 108.

The specific configuration of the charging circuit 108 is as shown in FIG. The interface circuit 111 interfaces with the demultiplexing circuit 103 and the multiplexing circuit 107, the encryption / decryption circuit 116 performs encryption and decryption with the key k, the random number generation circuit 115 is for generating RN, and the microprocessor 114 is Random number generation circuit 115, encryption / decryption circuit 116, interface circuit 11
Control 1 and so on. Specifically, the flowchart shown in FIG. 4 is executed. The ROM 112 stores a program of the microprocessor 114, a key k, and information necessary for billing such as a call charge RT, and the RAM 113 is a work area of the microprocessor 114.

FIG. 4 is a flowchart showing the work to be executed by the microprocessor 114. Microprocessor 114 is PT
When a connection request (step 401) is received from the random number generation circuit 115, a random number RN is generated (step 402) and transmitted to the PT (step 403) to wait for a response from the PT (step 404). Microprocessor 114 changes from PT to RN, C
When the result of encrypting H and CR with key k is received (step
405), and the encryption / decryption circuit 116 decrypts (step 40
6), the RN is compared with the generated random number (step 407). If they are not the same, the connection request is rejected as an error or tampering (step 408). If they are equal, connection is made (step 409), and if a call is started, billing (step 410) is performed. If CH> CR (step 411) or the call ends (step 412), the call is disconnected (step 413), the new CH is encrypted by the encryption / decryption circuit (step 415), and transmitted to the PT (step 416). , PT waits for a response (step 417). Microprocessor 114 is PT to E
_{When k} (RN2, ANS) is received (step 418), the encryption / decryption circuit 116 decrypts it (step 419). If RN2 is correct (step 420) and ANS is ACK (step 421), the process ends (step 422). RN2 is incorrect or ANS is A
If it is not CK, it is considered to have been erroneous or tampered with. In this case, if the number of retransmissions CT exceeds a predetermined number of times CN (step 423), an alarm is issued to notify the subscriber information center without performing retransmission (step 42).
Four). Alternatively, the center may be notified directly. If CT does not exceed CN, the encrypted CH is sent to PT again (step 415), and PT waits for a response 416
become. The number of retransmissions is set to 1 when the encrypted CH is first transmitted to the PT (step 414), and is incremented by 1 each time it is retransmitted (step 425).

In this embodiment, random number generation and encryption / decryption can be executed by a microprocessor. If the guarantee amount CR is a fixed amount, it is not necessary to notify BS to each PT. Also,
Instead of CH, PT memorizes the balance CS for CR, and it is possible to reduce 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. The key to be used in the future can be set in advance and stored. It is also possible to divide all PTs into several groups, set a key for each group (denoted as a group key), and store all group keys in the BS so that they can be used 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, CH,
If CR) is sent instead of E _k (RN, CH, CR), BS can decrypt it and if TM is close to the time then 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 RN
When sending, encrypt with k. 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, if the present invention is used, the base station, not the subscriber information center, can perform the charging process, so that the charging can be performed with almost no increase in the network side processing and communication amount.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the operation and principle of the present invention, FIG. 3 is a schematic diagram of an example of a system to which the present invention is applied, and FIG. 3 is a flowchart showing the work executed by the microprocessor shown in FIG. 101, 105 ... Antenna, 102 ... Receiver, 103 ... Demultiplexing circuit, 104 ... Line supervision frame, 106 ... Transmitter, 107 ... Multiplexing circuit, 108
…… Billing circuit, 111 …… Interface circuit, 112 ……
ROM, 113 ... RAM, 114 ... Microprocessor, 115 ...
… Random number generation circuit, 116 …… Encryption / decryption circuit, 201 …… Personal telephone side, 202 …… Processing related to base station charging, 3
01,302,303,304 …… Personal telephone, 311,312,313 ……
Base station, 321,322 …… home phone, 331 …… subscriber information center, 341 …… public telephone network, 401 …… connection request step,
402 ... random number RN generation step, 403 ... RN transmission step,
404 ...... response waiting _{step, 405 ...... E k (RN,} CH, CR) receiving step, 406 ...... decoding step, 407 ...... validity determining step of RN, 408 ...... call cutting step, 409 ...... connection Step 410 410 Billing step 411 CH CH comparison step 412 Call termination step 413 Call disconnection step 414 Retransmission number CT set to 1 step 415
...... CH encryption step, 416 ...... Encrypted CH transmission step, 417 ...... Response waiting step, 418 ...... E _k (RN2, RN
ANS) receiving step, 419 ... decoding step, 420 ... RN2
Of the validity of 421 ... determination step of whether ANS is ACK, 422 ... end step, 423 ... retransmission number determination step, 424 ... alarm generation step, 425 ...
... a step of increasing the number of retransmissions by 1.

Claims (1)

[Claims] 1. A storage unit for storing an encryption key previously shared with a terminal that intends to use a pay service, an identifier generation unit for generating an identifier for identifying a connection request from the terminal, and the identifier. A first identifier conversion unit and a second identifier conversion unit for converting based on a rule shared in advance with the base station; an encryption unit for performing encryption and decryption using the encryption key; and the terminal. It comprises a communication means for communicating, a service control means for starting or terminating the service to the terminal, and an abnormality notifying means for notifying the occurrence of an abnormal situation to the outside. Received through
The identifier is generated by the identifier generation means and transmitted to the terminal via the communication means, and then the identifier encrypted from the terminal via the communication means and the fee of the pay service already received at the terminal After receiving the cumulative amount of and the upper limit value of the cumulative amount, these are decrypted by the encryption means,
If the decoded identifier does not match the previously transmitted identifier, the communication with the terminal is terminated, and if the identifier matches, the service control means starts the service to the terminal and charges the service. If the accumulated amount exceeds the upper limit amount or there is a service termination request from the terminal, the service is terminated by the service control means, and then the first identifier conversion to the identifier is performed. The result of conversion by the means and the accumulated value are encrypted by the encryption means and transmitted to the terminal through the communication means, and when there is a resend request from the terminal, the sent contents are resent. When the encrypted identifier after conversion and the notification that the processing has been normally completed are received from the terminal, the converted identifier and notification are sent to the encryption means. Then, the result obtained by applying the second identifier converting means to the converted identifier and the previous identifier is compared, and if they match, the processing is terminated, and if the comparison does not match, The terminal is requested to resend and repeats until the comparison agrees, and when the comparison is repeated for a certain number of times or there is no response from the terminal after a certain period of time, the abnormality notification means notifies the outside of the occurrence of an abnormal situation. A billing device characterized by the above.