System, method and apparatus for secure transmission of confidential information

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

Cross-reference to related applications This application is filed by the applicant in US Patent Application No. 09 / 02,289, "System, Method and MFP for Secure Transmission of Confidential Information" (February 11, 1998). A partial continuation of the Japanese application and the ongoing US Patent Application No. 08 / 845,938 by the Applicant, "Combined Mobile Telephone and Remote Control Terminal." "(19 (Applied April 29, 1997) is incorporated herein by reference.

【0002】

1. Technical field to which the invention belongs Overall, the invention establishes a secure wireless communication link between two devices that minimizes the risk of a third party intercepting sensitive information, such as those exchanged during the communication initialization process. Regarding systems, methods and equipment.

【0003】

2. Background and purpose of the present invention The British Sea in 1897 by Guglielmo Marconi Since the demonstration of wireless capabilities that enable continuous communication with vessels navigating the canyon, the innovation of wireless communications in this century has been remarkable. Since the discovery of Marconi, new wired and wireless communication methods, services and standards have been adopted by people around the world. This innovation has been accelerated, especially in the last decade, during which the mobile wireless communications industry has grown many times and technologies that make portable wireless devices smaller, cheaper and more reliable. It has been boosted by progress. Mobile phones will continue to grow exponentially over the next decade, interacting with existing wired networks, and will eventually overtake existing wired networks.

【0004】

Cordless phones are also part of the exponential growth in wireless phones. Cordless phones were originally intended to use indoor, economical cableless voice communication, a short wireless link that replaces the cord between the phone body and the handset. Early cordless phones were of insignificant quality, but sales increased dramatically with the introduction of improved cordless phones in the 1980s. More recent advances, especially in Europe, have extended the reach of cordless phones to the outdoors.

【0005】

Another innovation in Europe for cordless phones is the digital enhanced cordless communications (DECT) standard, which is optimized for use inside buildings. The DECT controller hands off connected calls from one base station to another as the user moves, and calls or rings the handset as the user passes through areas covered by different base stations. Can be done. As is understood in the art, the range of movement of cordless phones is very limited compared to more versatile cellular phones. That is, while the range of cellular telephones is 0.3 to 30 km or more, that of cordless systems is less than 100 m, usually only several tens of meters.

【0006】

More recently, the world of cellular and cordless telephone technology has begun to converge with the introduction of cordless standards that are compatible with cellular standards. Thus, cellular users can use the terminal within a cordless phone system, eliminating the need to purchase a dedicated, typically incompatible cordless phone. Figure 1 shows at least one private base station 12 and communication with this base station. A private telephone system 10 having a plurality of cellular telephones 14 in the medium is shown. In cordless mode, the cellular user, for example in telephone 14A, communicates with another user in the private telephone system 10, such as another cordless mode cellular telephone 14B or cordless telephone 16, via a private base station 12 acting as a relay. can do.

【0007】

One issue with using cellular phones 14 in private telephone systems is security. As mentioned above, the original cordless phone, eg the phone 16 in Figure 1, is a stand-alone consumer product. It didn't require any interoperability specifications. In other words, each cordless phone has its own base station and only needs to be compatible with that base station. Billing, security and privacy matters in such systems have been dealt with by limiting the transmission distance of the cordless phone without operating the cordless phone with other base stations. However, due to the convergence of cordless telephone technology and cellular technology, the physical restrictions inherent in cordless systems no longer work as a security function. The use of a cellular telephone 14 capable of transmitting signals for miles within a private telephone system 10 raises a genuine security consideration.

【0008】

As is known in the art, the cellular phone 14A can communicate through private base station 12 using an encryption key or other similar security protocol, thereby encrypting and more decrypting the message. It becomes difficult. Therefore, conversations or data exchanges are relatively confidential, although communications from cellular users communicating within the range of private telephone system 10 will reach well beyond the reachs of system 10. Be kept. However, during the initialization of communication via the wireless interface, no encryption key is exchanged with the cellular user, for example, the cellular terminal 14A, and unencrypted communication is always performed, which causes another problem. appear. As a result, information including cryptographic keys is widely broadcast until a cryptographic protocol is established. Therefore, a third party may intercept such unencrypted communications and obtain sensitive information.

【0009】

Various techniques can be used to prevent such eavesdropping. The first approach is that the cellular telephone 14A must be electrically connected to the private base station 12 in order to initiate private communication in order to use a wireless connection for exchanging initialization information. Therefore, this approach requires the provision of an electrical interface between the two components, and standardized connectors will increase the size and weight of the terminal, making it attractive to manufacturers. It will limit the degree of freedom in designing the terminal. Moreover, such provisions will limit further improvements to the telephone 14, such as the transition to low voltage technology for miniaturization and energy savings.

【0010】

Another approach uses subscriber identification modules (SIMs) on both the private base station 10 and the individual cellular phones 14, which allow the required identification information to be easily established and a legitimate key applied without transfer. Will be done. In addition to the cost of the added parts, the use of two SIMs in this way is the use of private base stations 20 and individual cellular terminals 1 For mobile network operators who must assign a unique SIM pair to and from 4 Brings an increase in management costs. In addition, the SIM for cellular terminal 14 is a private base station 1 There is a risk of being inserted in 2, which further complicates this approach.

【0011】

The third approach takes advantage of wireless interfaces, such as being standardized. However, as already mentioned, radio waves propagate widely through walls, so this property also poses a security risk that must be resolved.

【0012】

In view of the problems of each of the approaches described above, a simple and secure system and method for establishing a communication link between a first device such as a cellular telephone and another device such as a private base station. Is clearly needed.

【0013】

Therefore, an object of the present invention is to establish a simple and secure communication link in which at least a part of communication, particularly a part containing confidential information, is clearly transmitted for correct reception and at the same time minimizes the risk of interception. To provide systems, methods and equipment to do so.

【0014】

Another object of the present invention is to provide confidential or important information for establishing a connection between first and second devices communicating over a wireless link, such as peripheral devices such as laptop computers and printers. The purpose is to provide a system, method and device for safe transmission.

【0015】

Yet another object of the present invention is to provide a secure wireless transmission link for a computer that receives internet commands between any two devices at work and at home, such as turning on a heater in an apartment. After a secure link has been established using the systems, methods and devices according to the invention, the two devices are wireless radio without the use of dedicated cables or other physical interconnects. Communication is possible via link).

【0016】

(Outline of the invention) The present invention establishes a secure wireless radio communication link between two devices that minimizes the exposure of critical information to interception by a third party. The purpose is to provide systems, methods and equipment. A secure link is established by establishing an infrared link between the two devices for exchanging important information such as cryptographic information.

【0017】

A more complete application and scope thereof of the present invention can be obtained from the accompanying drawings briefly summarized below, followed by a detailed description of currently preferred embodiments of the invention and the scope of the attachment.

【0018】

[Example]

(Detailed description of a specific embodiment preferable at present) The present invention will be described in more detail below with reference to the accompanying drawings showing the present invention. However, the present invention can be implemented in many different forms and should not be limited to the configurations of embodiments described below, but rather these embodiments are sufficient and complete in the present disclosure and are skilled in the art. It is provided to convey the scope of the present invention to the fullest extent.

【0019】

The use of infrared (IR) transmission between various electronic devices, such as between a television and a remote control, is, for example, U.S. Pat. No. 5,508,836, which discloses various IR electronic interconnects. Known by Nos. 5,588,009, 5,564,020, 5,617,236 and 5,446,783. U.S. Pat. No. 5,636,264 also applies to telephone handset and computer. Disclose the IR interface between data. Although it is disclosed that IR is used for these contents, all of these references refer to the above-mentioned security problems specific to wireless communication, as well as the solutions presented by the present invention, which will be described in more detail below. Not mentioned.

【0020】

FIG. 2 shows a dual-mode mobile station 20 communicating with a dual-mode private base station 21. As mentioned above, the mobile station 20 communicates with the private base station 21 via RF transmission with an effective range of several hundred meters and a much shorter, more restricted "cordless" communication mode. As is known in the art, the RF transmission mode is via the individual antennas 20A and 21A of the mobile station 20 and the private base station 21, respectively, and the signals are transmitted and received in the usual way.

【0021】

FIG. 2 further shows the IR transmitter / receiver interfaces 20B and 21B of the mobile station 20 and the private base station 21, respectively. The individual interfaces preferably include a photodetector 22 for receiving IR signals and an IR signal generator 23 for transmitting such IR signals. Here, the positions of interfaces 20B and 21B in the main body of the mobile station 20 and the private base station 21 are arbitrary so that the individual IR signals to and from the interfaces 20B and 21B are not blocked, for example, the telephone user. It is provided so that it will not be blocked by the palm or fingers of the phone. In other words, as is known in the art, ergonomic studies may determine the specific location of the interface.

【0022】

Further, with reference to FIG. 2, one specific use of the dual mode mobile station 20 will be described. In particular, if the dual-mode mobile station 20 is within the more restricted range of the private base station 21, eg, in the same or adjacent room, the subscriber can make a cheaper radiotelephone to the public switched telephone network (PSTN), eg through a private system. Save on billing by price To switch control from a cellular provider to a private system You will think that. For example, through PSTN24, mobile station 20 can communicate with remote wired telephone 25 and further remote cellular telephone 26 via base transmitter / receiver system 27 (simply showing only base transmitter / receiver station tower).

【0023】

Referring to FIG. 3, the mobile station 20 (in FIG. 2), especially the IR transmitter / receiver interface. A number of circuits are shown that handle the IR signals inside the base station 20 and the base station 20. The IR receiver or photodetector 30 receives an IR signal from a private base station 21 or the like, and sends the signal to a decoder 31 that converts infrared information in the IR signal into electrical information, for example, a digital pulse. The converted information is then transferred to the controller 32, which controls the flow of electrical information (pulses). The signal conversion element 33 receives the above-mentioned flow of electrical information and groups the input pulses into a unit size (frame) according to the signal format of the base. The controller 32 may be a UART or other similar controller, as is known in the art.

【0024】

The converted input signal is sent to the processor 34. The processor 34 executes a command contained in the signal, for example, a command such as transferring an input signal to another telephone such as mobile station 14B (Fig. 1) via an RF communication link. Similarly, processor 34 can respond to one or more commands and send a message over the IR communication link as follows: That is, first, a message is transferred to the signal conversion element 33, the signal conversion element 33 converts a message having a predetermined configuration (structured message) into the above-mentioned electrical information or pulse, and the controller 32 transfers it to the encoder 35. Send. The electrical pulse is converted into an IR radiation signal, which is transmitted by, for example, an IR transmitter 36, which is a light emitting diode that emits an IR signal.

【0025】

Of course, it should be understood that the circuit shown in FIG. 3 should also be incorporated into the private base station 21 so that the wireless IR dialog can be established with the mobile station 20.

【0026】

As mentioned above, the effective range of the IR signal radiated in this way is limited to the order of several times 12 m. Obstacles such as walls, floors and ceilings further reduce the effective range, as consumers encounter with products such as TV remotes. Thus, IR signals are wireless, preferably transient, but effectively limiting communication for point-to-point conversations until a secure protocol is securely established. Provides a sophisticated way to exchange sensitive information. Eavesdropping is still possible, but is hampered by such range restrictions. That is because another security method, such as building control, will be used in conjunction to provide almost all levels of interception protection.

【0027】

Wireless communication between users of the dual-mode telephone 20 (in Figures 2 and 3) is possible because various encryption methods are available for conducting wireless conversations with little concern for code-breakers. It more preferably switches to RF communication mode to take advantage of stronger security to thwart decryption. However, wireless RF communications, even encrypted, can easily be intercepted by distant eavesdroppers. Encrypted data will prevent decryption of intercepted encoded messages, but callers and called parties are first able to monitor eavesdroppers and easily unencrypted radios. Cryptographic keys must be exchanged through a switch via communication to establish secure transmission. As a result, the eavesdropper can easily crack the associated key and crack the transmission content that is believed to be securely encrypted.

【0028】

The systems, methods and devices according to the invention are improved and more secure, preserving the confidentiality of wirelessly transmitted information by limiting the exposure of cryptographic keys and other sensitive information through the IR transmission described above. Provide a method.

【0029】

In one embodiment of the invention, the mobile station 20 is configured so that the subscriber of the mobile station 20 is sufficiently close to the private telephone system, eg, the private base station 21, to output an IR signal, eg, via the IR transmitter 36. Activate. Alternatively, the mobile station 20 can automatically activate its IR signal handling capability before sending or receiving security-related data. In a preferred embodiment of the invention, the mobile station performs all non-confidential transmissions, such as at initialization of communication with a cordless telephone base station such as private base station 21 and after exchanging encryption keys and other sensitive data. Normal radio frequency is used for various transmissions. In response to the arrival or protocol of the above-mentioned sensitive data in transmission, the mobile station 20 switches to the above-mentioned IR signaling using the IR transmitter 36. Here, the switching from RF to IR may occur at an early stage of transmission, for example, at the time of initial communication trial, or in subsequent transmission, as long as the confidential portion of the signal is transmitted by IR transmission.

【0030】

In any case, the private base station 21 detects the IR signal transmission from the mobile station 20 via the internal photodetector 30 described above, processes the incoming IR signal, and processes the IR response signal, preferably the encryption. Respond with an IR response signal containing the key. Here, one or more encryption keys may be inserted into the response signal by the encryption circuit 37 communicating with the processor 34. Upon securely receiving one or more encryption keys from the private base station 21 via IR transmission, the mobile station 20 securely initiates / resumes wireless RF communication encrypted according to the attached encryption key. And, as mentioned above, subscribers will be able to move more freely inside the building while using cheap wired communication links through PSTN24.

【0031】

In another embodiment of the invention, the private base station 21 can periodically generate an IR signal that the mobile station 20 can intercept when close enough. In fact, private base station 21 can perform IR polling to establish a preliminary IR linkage for exchanging sensitive information such as the encryption keys described above. For example, in response to detection (in photodetector 30), mobile station 20 may include an encryption key that governs subsequent RF transmission with private base station 21 (like private base station 21 in the previous embodiment). It is also possible to respond with an IR response signal, thereby providing a procedure for periodic or irregular security measurements.

【0032】

In yet another embodiment of the invention, the subscriber of mobile station 20 or the administrator of the private telephone network may use other, more secure IR communication links to transmit non-initialization related information. it can. For example, if it is necessary to transmit particularly important information during RF transmission, the mobile station 20 and private base station 21 should switch to a more private IR communication mode and return to RF mode transmission after the important information has been transferred. Can be done. Here, the mobile station and the private base station 21 can automatically return to the IR communication mode while they are within the range of each other, and can be switched only when the quality of IR transmission starts to deteriorate.

【0033】

One preferred embodiment according to the invention utilizes the principles of the invention with respect to mobile phones, but the scope of the invention is a number of duals using infrared mode for security purposes, as described in the claims below. It should be understood to cover modal wireless interconnects.

【0034】

FIG. 4 shows another embodiment of the invention in a first device that communicates with at least one of a number of other devices, such as mobile phones, users or computer headsets. The first such device came out on April 29, 1997. See US Patent Application No. 08 / 845,938, "Combined Mobile Telephone and Remote Control Terminal," which is the applicant's ongoing patent application. Explained and all of the applications are published Incorporated as a reference in the request. It should be understood here that although all of the many devices shown in FIG. 4 can communicate with each other, they are not used (at this time) for certain combinations. For example, the television 68 can transmit images for printing on the printer 50, but the printer 50 (which receives commands from a personal computer or PC 48) does not need to communicate with the television 68. However, the printer 50 can properly transmit the print completion (or a piece of paper or an error message) to the PC 48 (using security measurements by this application or otherwise).

【0035】

Recent initiatives such as the Bluetooth mobile communication concept are often used at work or at home. It promotes the enhancement of interoperability of various electrical, electronic and mechanical devices. Figure 4 shows a home base linked to the regular public switched telephone network (PSTN) 42. A wide variety of devices that can use Bluetooth and other similar technologies, including station) 40, have been shown, and they are other devices, such as dual-mode phones 26 (Figure 2), wireless headsets / hands-free. Converts radio rf and infrared signals received from unit 44 or other cordless device 46. Desktop or laptop PC48 can also be downloaded in both directions, for example Printer / Plotter / Projector 50, Facsimile 52, Pocketbell 54, Data Organizer 56 or (Important Information from Organizer 56 to /), PC48, Other PC58 or Other similar personal and small organizer devices (which can synchronize the data stored in the electronic data terminal 58) are commonly shown as many additional peripherals, scanner 60, microphone 62, PC card 64 and reference number 66. Can interact with many similar peripherals. Of course, as shown in FIG. 4, the principle of the present invention is also applicable to the mobile station 26 and its associated SIM card 26A, and the SIM card 67 separate from the mobile station 26.

【0036】

In the home, many other home appliances may have dual-mode functionality as described in the present invention. For example, the PC 48 can intercommunicate with a television 68, radio 70, stereo 72 or peripherals connected to the stereo, a VCR or other video player 74 (tape or disc). You may. Other interconnected devices in the home are lighting device (lamp) 76, dimmer switch 78, thermostat 80 to control heating / cooling of the house, door device 82 such as garage door, refrigerator / freezer 84, Includes cooking device 85 (microwave oven, gas range, etc.), washing machine / dryer 86, answering machine 88 and alarm device 90. Further devices that may include the original techniques of the present invention need to be in close proximity to operate in infrared mode, preferably with nothing in between (having a car locking function) car alarm. The device 92 and other fixed security alarm devices may be included.

【0037】

Using the principles of the present invention, secure communication is established via infrared and wireless links. Thereby, the user opens the garage door 82 by entering a command by voice or key input into a portable device or a wrist-worn (clock-type) communication device, which is generally described, for example, by reference number 94. You can get off, lock the car, unlock the home alarm device 90, and enter the heated / cooled home by remote command (wirelessly relayed by PC48) given to the thermostat 80 in advance.

【0038】

Devices that are wirelessly interconnected as specified according to the Bluetooth concept Many will be expensive and awkward to handle today, and will replace dedicated wired transmission with low-cost, short-range wireless links. However, it should be understood that the need for safe RF transmission with a range of 100 m or more is very important. Because those communications are easily eavesdropped, intercepted and deciphered by unauthorized users, thereby personal property. This is because it is possible to gain access to production and property. Safer infrared transmission according to the present invention requires close enough proximity, but more directional sensitive data exchange is required for such open-to-tampering systems. Provides an essential level of protection.

【0039】

The frequency spectra available for these private applications are currently quite limited. For example, in the United States, the 900MHz, 2.4GHz and 5.7GHz bands are not currently licensed and are free to use if the transmit (TX) power level is low or diffused. Bluetooth concept is globally available 2.45GHz It is planned to operate in the "free frequency band" for industrial, scientific and medical (ISM), and overseas travelers can use Bluetooth compatible devices all over the world. Avoid interference Therefore, it will be understood by those skilled in the art that frequency hopping (FH) or direct series (DS) spread spectrum should be applied.

【0040】

The 2.45 GHz ISM band is used by a wide variety of devices, as described in the simultaneous filing of patent applications by the same applicant, "Method and MFP for Tracking a Mobile Phone." In addition, the frequency band is composed of a range of about 2.4 GHz to about 2.48 3 GHz. In an effort to avoid abrupt characteristic filters to meet out-of-band radiation requirements, the applicable radio frequency band is preferably ISM, as described in the description of frequencies in this patented telephone tracking system. It is placed away from the edge of the band. 2.435 GHz to 2.465 GHz, for example, where a microwave oven operates, which is known as an interference region, is preferably avoided as well. Frequency shift keying (FSK) can be used to map the user code to the RF carrier.

【0041】

In FSK modulation technology, the bit representing "1" is mapped to the frequency of RF + Df, and the bit representing "0" is mapped to the frequency of RF-Df (or vice versa). Here, RF is the carrier frequency and Df is the frequency deviation, which must be sufficiently large with respect to the frequency offsets of the transmitter and receiver. For example, if an inaccurate frequency reference (with an accuracy of about 50 millionths) is used, the frequency offset can reach 240 KHz in the worst case. In order to receive a burst in such a case, the frequency deviation Df needs to be larger than 240 KHz.

【0042】

Although described here with reference to GSM technology, the principles of the present invention are other time division multiple access (TDMA), personal digital cellular access (PDC) and third generation systems and devices currently under development (or in the future). Can also be used for. Therefore, various frequencies used by these and other systems, such as the 800,900,1500,1800,1900,2000 and 2100MHz bands, can also be used in the systems, methods and devices of the present invention.

【0043】

The above description relates to preferred embodiments for the implementation of the present invention, and the scope of the present invention is not necessarily limited to this description. Rather, the scope of the present invention is defined in the following claims.

[Simple explanation of drawings]

[Figure 1]

It is a schematic diagram of a private telephone system including a private base station and a cellular telephone and a cordless telephone communicating with this private base station. [Figure 2]

It is a figure which shows the dual mode radio frequency and infrared mobile station, and a private base station by this invention. [Fig. 3]

It is a figure which shows a number of circuits using the dual mode apparatus shown in FIG. [Fig. 4]

It is a figure which shows a number of devices which communicate with each other using the principle of this invention.