JPS60176339A - Radio calling system - Google Patents

Abstract

PURPOSE:To make wiretap of a message difficult even if the call number of a receiver is opened to the public, by allowing a radio calling station to select one of plural kinds of ciphering method of indication information and cipher indication information when the station transmits indication information to the receiver. CONSTITUTION:The person who wants to carry the receiver reports to a radio calling service station, and the call number of the receiver is given to him, and he designates one of ciphering methods. The station writes the call number of the receiver and the designated ciphering method in a file of an electronic exchange. In case that messages are transmitted to the electronic exchange and the receiver, this transmission is performed on a basis of the call number and ciphering information stored in the file. For example, when indication information ''1, 2, 3, 4'' is transmitted to a receiver (d) of call number ''1'', the call number is transmitted in the POCSAG code standard form, but indication information is transmitted after being ciphered by the ''1'' and ''0'' inverting method. When this indication information is transmitted to a receiver (e) of call number ''2'', it is transmitted after being ciphered by the method where information is transmitted in the reverse order in 4-bit units.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a radio paging system. In particular, it concerns the encryption of subscriber information.

[Description of prior art]

The radio paging system, conventionally known by names such as ``Bokent Bell'' and ``Radio Page Naka,'' is a system in which an ordinary telephone subscriber calls a portable telephone receiver through a public telephone line.

In the early systems, the receiver only made a sound or vibrated when it detected a call signal, so the person carrying the receiver would have to make arrangements in advance when receiving a call. It was used by calling a specific telephone number (for example, home) and asking the purpose of the call. In other words, the number of people who could make a call was limited to a practical limit.

A more advanced system has been put into practical use, in which a liquid crystal display or the like is installed on the receiver to transmit a message in addition to the calling signal. In such a message-attached system, anyone can make a call by transmitting the caller's telephone number and name as display information.

Therefore, in the early systems, if a person carried a receiver, it was necessary to tell the call number of the receiver to a limited number of people, for example, only to family members, but under a system that allows message transmission, it is necessary to share the call number of the receiver with a large number of acquaintances. In many cases, the recipient will be given the number of his/her own receiver.

By the way, in a paging method that allows message transmission,
It is also possible to use it for the purpose of message transmission itself, rather than for making calls. In other words, for example, when you want to know about market price fluctuations while away from home, you can send hourly prices as a message.

In this manner of use for message transmission, if personal information or highly confidential information is to be sent as the contents of the message, confidentiality becomes an issue.

Zunawaji, as mentioned above, the call number of the receiver is disclosed to many acquaintances, so it is easy for someone who knows the call number to copy the receiver in order to eavesdrop on messages. become.

[Purpose of the invention]

The present invention is intended to solve the above-mentioned problems, and aims to provide a means for making it difficult to eavesdrop on messages even when the calling number of the receiver is made public.

[Features of the invention]

In a radio paging system that broadcasts subscriber identification signals and display information, the present invention has multiple types of encryption methods for display information, and each subscriber selects one of the encryption methods to display display information. It is characterized by being encrypted.

[Explanation of Examples]

An embodiment of the present invention will be described with reference to a system using an electronic exchange connected to a general telephone network.

Those who wish to carry a receiver must submit a notification to the organization in charge of the radio calling service and receive a calling number for the receiver, at which time they must specify one of several encryption methods.

The receiver has switches and read-only memory (ROM).
) etc. to set the calling number, and also make settings for decryption corresponding to the specified encryption at the same time.

The agency in charge of the radio calling service writes the subscriber's calling number in a file called subscriber data in the electronic exchange, and also selects which encryptor (not shown) the receiver will use. Also write the information to do so.

When such an electronic exchange receives call and message information from the general telephone network, the electronic exchange refers to the subscriber data file to create a called number, and then forwards the message as specified in the subscriber data file. Encrypt with the selected encryptor.

These calling numbers and message information are broadcast from a group of transmitters connected to the exchange.

When the receiver detects a signal, it first checks to see if the calling number matches the value set in the switch or ROM, and if it matches, the message information is sent to the switch or ROM.
It is decoded and displayed according to one of the decoding methods set in M.

In order to further explain the present invention in detail, the accompanying drawings show examples of signals that are actually broadcast. The explanation will be given below according to the same figure.

The figure is a signal format diagram of an embodiment of the present invention. Figure P
The signal format is called the OC5AG code, and it begins with a 576-bit preamble (PREAMB) that indicates the beginning of the signal.
LE) signal, followed by a 32-bit synchronization signal indicating the boundary between the preamble signal and the ringing signal, followed by the 32-bit
A large number of call signals or display information signals having a length of bits are transmitted (0 to 15 in the figure (al)).

Figure (bl) shows a detailed enlarged view of the calling signal and display signal.

Furthermore, the meaning of each component is shown in Tables 1 and 2.

Figure (cl shows a four-character number (rl) as an example of display information.
, 2, 3, 4J,) is shown below. However, this example is a method of sending when the present invention is not applied.

The following figures (dl and (e)) are examples of the case where the present invention is applied to the POC3AG code.

Figure (dl) shows the case where the numerical information "1.2.3.4" (same as the example of C1) is sent to the receiver with subscriber number "1".The calling number is shown in the diagram (bl). This is a standard format, but the display information part of the display signal is "1 and 0".
It is encrypted using a method called "reversing the data."

On the other hand, Figure (el) shows the case where the same numerical information "1.2.3.4" is sent to the receiver with subscriber number "2".The calling signal is shown in Figure (b). This is a standard format that differs from the one shown in Figure +d+ only in the subscriber number.However, the display information part of the display signal (unlike the dl example, is "sent in reverse order in units of 4 bits") It is encrypted using this method.

Therefore, if subscriber No. 2 changes the number of the receiver to 11.
Even if the number is changed to number j, the display information originally addressed to number "1" is not decrypted correctly because the encryption method is different.

The above example is an example in which only the display information portion of the display signal is encrypted, but it is also possible to darken the entire display signal.

In addition, it is not limited to "inversion" or "order reversal" encryption.
Various types of encryption are possible.

C. Effects of the Invention] According to the radio paging system capable of transmitting messages according to the method of the present invention, a duly registered person carrying a receiver can receive a call in exactly the same way as in the case of a radio paging system to which the present invention is not applied. It is possible to send and receive messages, but it is almost impossible for others to eavesdrop on messages.

An eavesdropper can easily know the calling number of the person carrying the legitimate receiver, but it is impossible to infer how the message is encrypted from the calling number. It's almost impossible to read the i-summer issue even if it is.

[Brief explanation of the drawing]

The figure is a signal format diagram of an embodiment of the present invention, (al is an overall diagram, (
b) to (e) are detailed enlarged views of a portion of (al). Patent applicant: NEC Corporation Representative Patent attorney: Naotaka Ide

Claims (1)

[Claims] (1) A small number of base station devices that broadcast radio signals, and a large number of portable receivers each equipped with means for receiving and displaying the radio signals, and each assigned a unique calling number. Preparation: The radio signal includes a calling number assigned to each of the receiving devices, and each of the receiving devices is provided with means for checking the calling number of the received radio signal with its own calling number, and this means The means for displaying a reception indication is configured to display when a match is detected by the base station apparatus, and the base station apparatus further includes means for broadcasting a message following the calling number, is a radio paging system comprising a means for displaying a received message following its own calling number, wherein the means for broadcasting the message includes means for encrypting the message according to an encryption rule; The means for displaying includes a means for decoding the encrypted message according to the above encryption rule, and the above encryption rule is one in which several different encryption rules are assigned to a large number of receivers. A wireless paging system characterized by: