DE19917047A1 - Communications method involves automatically generating a code word exchanged between transmitter and receiver for encoding transmitted information and decoding received information - Google Patents

Abstract

The method involves automatically generating a code word at one end, transmitting it to the other end, encoding information using the code word at the transmitter end, receiving information at the receiver end and decoding the received information using the code word. A new code word is generated on defined occasions using a random process. Independent claims are also included for: (1) a transmitter unit; (2) and for a communications system.

Description

The present invention relates to a communication method, a Transmitter unit, a receiver unit and a communication system from receiver and transmitter unit.

Such a communication method or system is used in particular for realizing a remote control for entertainment devices electronics such as B. HIFI or television sets, for decoders of all Types of pay TV as well as for "tele-shopping", "home banking" or similar Facilities.

In the applications mentioned, it is desirable in certain cases that Personalize the transmitter side - i.e. a remote control unit - d. H. out finally on the interaction with a certain recipient side - well the device to be operated. The device to be operated should thereby before operation and before misuse by other remote controls units are protected. This is particularly necessary when using commercial applications (transactions) are to be carried out on the device, such as calling up a movie (if this device is used as a decoder, e.g. d-box is configured), ordering goods as part of tele-shopping or performing a banking operation on home banking. Fernbe service unit and receiver unit already during manufacture Corresponding hardware settings are permanently assigned to each other, however this represents a considerable cost factor in the mass production of the devices represents, especially when remote control unit and receiver unit  are manufactured or sold separately. It is similar when personalizing devices using chips or smart cards that pro grammed PIN keys included. This measure leads to complications if the user forgets his PIN code or loses the chip card.

The aim of the invention is therefore a communication method, a transmitter unit, to create a receiver unit and a communication system, which a simple, yet sufficiently reliable option for personali Ensure remote-controlled devices during operation. This Target is achieved by a method having the features of claim 1, by a Transmitter unit with the features of claim 17 or 19, a receiver unit with the features according to claim 25 or a system with the notes paint achieved according to claim 33. Advantageous further developments are in the Subclaims defined.

According to the invention, a communication method between one Provided transmitter side and a receiver side, in particular being between Transmitter side and receiver side no wire, fiber or other solid Communication connection exists, which is carried out by the following steps is marked: Automatic generation of a code word on one of the Pages, transmitting the code word to the other side, encrypting Information using the code word on the transmitter side, sending from Information from the sender side, receiving information at the receiver page and decrypting the received information using the Code word.

The transmitter unit according to the invention for communicating with a receiver page has: Means for entering a transmitted from the recipient side  Codeword, means for encrypting information using the Codeword and means for sending information.

Alternatively, the transmitter unit according to the invention has means for generating a code word, means for transmitting the code word to the recipient page, means for encrypting information using the code words and means of sending information.

According to the invention, the receiver unit for communicating with a Sender side on: means for generating a code word, means for transmission of the code word to the transmitter side, means for receiving information and Means for decrypting information using the code word.

According to the invention, the communication system has at least one transmitter unit and at least one receiver unit.

The invention has a number of advantages. That's how it works Generate the code word by one of the two sides and transmit the Code word to the other side a clear and exclusive assignment of both Sides, so a personalization of the two sides to each other. This assignment occurs immediately before information is sent, so it is not preset. Thus, the devices can be mass-produced inexpensively, since there is no factory assignment of the transmitter / receiver units.

According to a further aspect of the invention it can be provided that predetermined or regular occasions a new code word is generated. This creates a further increase in security against abuse, as a result  once personalized transmitter / receiver side again on regular occasions will be annulled.

According to a further aspect of the invention, the code word can be generated using a Random process are generated.

Furthermore, the transmitted information can contain control information. This serves the increase in the reliability of information transfer between the the sides.

Furthermore, it can be provided that the information to be transmitted is dependent encrypted by their type using the code word or un encrypted is sent. This is particularly advantageous if you are too transmitting information linked to varying security needs are.

Provision can also be made for a third party to report whether is sent encrypted or unencrypted. By means of this measure - For example, for billing purposes or for security reasons - the operating status the transmitter / receiver side are monitored from the third side. This third Page can e.g. B. be a program provider (provider) with which one of the Device connected to the receiver side can connect.

Alternatively or in addition to generating the code word depending on the The type of information to be transmitted can also be provided that the Generation of a code word from a third party (e.g. the program provider) is initiated. This serves to control and monitor the recipient device assigned by the third page.  

In the method and the units according to the invention, it can also be provided that the transmitted code word on the transmitter side by means of a character input device, in particular to enter a keyboard. This creates a special one uncomplicated operation for one user. Then it is too particularly advantageous if the code word on the receiver side and / or on the sender side can be made visible.

The units according to the invention can be manufactured inexpensively achieve if an infrared, radio or Ultrasonic connection between the transmitter side and receiver side is used.

It is also advantageous if the code word on the transmitter side is based on previous key presses is generated. This creates a quasi-random Generation of the code word and also enables a closer assignment of Sender and receiver side, since in the generation the "history" of Key presses received in the system.

It is particularly advantageous to the inventive method and the units for remote control of an entertainment electronics device tronics, especially a digital decoder box. Especially with derar term devices creates the personalization achieved according to the invention an increased Operational safety while maintaining a high level of user-friendliness.

The invention is described in more detail with reference to the drawing. In the drawing shows:

Fig. 1 shows a first embodiment of the invention,

Fig. 2, the operation of the remote control unit according to the first embodiment,

Fig. 3 illustrates the operation of a pseudo-random number sequences generator in the invention, and

Fig. 4 shows a second embodiment of the invention.

In the two exemplary embodiments, this is communication according to the invention Method and system for a decoder for a television set and a Remote control unit of this decoder realized. The decoder is one TV upstream and is used for selection, reception and decoding commercial digital applications such as B. television programs by third party terrestrial, cable or satellite. The Sender side of the communication system according to the invention is by the Remote control embodied, the receiver side is housed in the decoder or Part of this decoder. In the following, the recipient side is used for simplification itself also called a decoder.

In the first embodiment according to FIG. 1 and 2, the code word is generated in the decoder at the receiver side. Communication between the remote control and decoder is via an infrared connection. In the following, the term keyboard input is used as a generic term for commands, data and code words entered by means of the remote control. A distinction is made between three types of keyboard inputs corresponding to three operating modes of the communication system. The first operating mode corresponds to keyboard inputs with which simple operating functions of the decoder are controlled, such as. B. Navigation commands, volume change and confirmations. These keystrokes are not critical from the point of view of protection against misuse and are therefore transmitted without personalization of the infrared connection. The second operating mode, on the other hand, includes those keystrokes that trigger "protected" commands that are associated with financial obligations for the user, such as calling up a movie or ordering goods. These keystrokes are therefore transmitted with a personalized IR connection, i.e. with a personalized encryption. The third operating mode includes the entry of the code word that is used to personalize the IR connection for the commands of the second operating mode. These keystrokes are not transmitted; in their place, only one placeholder (e.g. an asterisk) is transferred.

The interaction of the IR receiver (IR receiver) in the decoder with the IR remote control when calling up an application (for example a film) by the user is described with reference to FIG. 1. The IR receiver has various function modules - an application layer, an IR handler, an event handler, CA subsystem (Conditional Access or access authorization subsystem) and a display handler (display control). that communicate with each other and with the remote control (RCU, Remote Control Unit). The modules can each be designed in hardware and / or in software. The modular structure enables the system to be partially retrofitted even after commissioning by the user or - in the case of implementation in software - to replace individual modules remotely by downloading from the provider and thus adapting them to changed technical or security requirements.

The application layer that is used to retrieve the application (e.g. a movie) serves, and the IR receiver in the decoder communicate via an An  application programming interface (API) with each other. The request to The user is responsible for changing over to the personalized operating mode initiation page. The application side receives from the communication system a brand (a flag) with the information which company mode is currently active.

Fig. 1 illustrates the guidance of the user through the three operating modes of the communication system using the example of a typical communication process between remote control and decoder over a horizontal time axis. If the user now wants to start a ("protected") commercial application (for example a film which is subject to a charge) which requires the second, that is to say the personalized, operating mode, he presses a corresponding shift key on his remote control. The decoder then checks whether a commercial application can be started at all. If not, the application is discarded from the start and the application is ended. If so, it is then checked whether the system is already in personalized mode. If this is the case, then the user is signaled that he can start retrieving the commercial application. If the system is not in the personalized mode, the system jumps to the third, i.e. the personalization mode. The current code word - a character string - is generated by means of the random generator in the decoder and shown to the user on a display of the decoder or on the television set connected downstream. The user enters this code word on the remote control keyboard. To control the user, each time a key is pressed, an asterisk is transferred to the decoder and shown on the display or screen. After entering all digits of the code word, the infrared connection between the transmitter side and the receiver side is personalized and the user is signaled that he can call up the application. The system is now in personalized mode. The commands entered by the user are encrypted using the code word and sent to the receiver side in the decoder via the personalized IR connection. There the received commands are decrypted again using the code word just generated. If the code word used for encryption matches the one for decryption, the commands are recognized as such and the commercial application is executed successfully, otherwise the application is prevented from starting, the user receives appropriate signaling, and the communication system falls into the first one , the non-personalized mode.

After successful execution of the application, the user is asked to exit the personalized mode. To do this, the user actuates a second one Times the aforementioned shift key on his remote control, and the system returns to the first mode. The pseudo-random number generator will reset. An interactive test routine can then be started. The user is asked to use the keyboard to run a test sequence for the to enter non-personalized mode.

The flowchart of FIG. 2 shows the operation of the remote control from operating the keyboard to sending out the corresponding information. The upper half of the flowchart represents a keyboard query. To the right of this is a schematic signal pattern for the query of the keyboard (rows / columns), which is applied cyclically to the columns. The lower, gray area shows the branching into the three operating modes of the communication system.

The keyboard query consists of a loop, which is a holding link and a Assignment operation contains and is cycled. That of the actuated The corresponding information is assigned to the actkey variable. Will one Key is pressed, this loop is exited and it is based on the value  first checked by actkey, whether it is the immediately before operated button. If so, then the previous broadcast action repeated without a new decision between the three Be drive modes needed. The box with a gray background is therefore bypassed (left Branch).

If actkey has changed the value, it is highlighted in gray when entering Box differentiated whether the key pressed is a number key or is an unprotected function key, for example for navigation. Act it is a numeric key [0 ... 9], then - after determining that the Fernbe service is in personalization mode (keyflag = 1) and not yet all digits of the code word PIN have been entered - while processing the entered key value a generator polynomial is formed and in the generator Register read, Gen Reg = f (actkey (PINCnt)). Sent to the broadcast then not the actkey key entered, but an unencrypted one Substitute characters (an asterisk) to which control blocks are added, such as e.g. B. a scrambling flag indicating whether the transmitted sequence is encrypted (ScrFlag = 1 or 0), and a word length count. This input cycle will repeated until all digits of the code word PIN have been entered. At the end of The generator polynomial is definitely defined, the IR Connection is thus personalized. This generator polynomial is then called used to encrypt the protected commands.

The functional sequence when transmitting the protected commands via the personalized IR connection is in the middle branch of the gray box shown. After determining that the system is not in Persona mode lisierens (query 3), the key value is first actkey by a Pseudo-random generator (Next Polynom 4) according to a standard procedure encrypted. The personalized encryption then takes place under Using the GenReg generator polynomial, which is generated using the  previously entered code word PIN is formed. The one so encrypted Information contained in the variable actkey 'is added with the addition of Control information - type, parity and length - sent out.

If, on the other hand, a key is pressed that is not a protected command is linked, it is sent out without personalized encryption. This mode is shown in the left branch of the gray box. The too sending command can - but does not have to - by a standard procedure (pseudo- Random number generator 4) are encrypted.

The operating mode is initialized in the upper part of the left path Form of the key flag (change key flag) and the reset that is controlled as a result of the generator polynomial and the variable PINCnt each to 0.

This ensures that the remote control after leaving the Scramble mode only after personalization with a new code word can be used again by the user for protected commands (Query 3).

A particularly reliable communication between remote control and Em Recipient is reached when an overflow status occurs with every key pressed is also transmitted (continuity = continuity). This will make the recipient enabled to use the random sequence used for encryption that of the remote control even while sending the individual commands adjust repeatedly. The random sequence gene jumps each time the button is pressed rator one step further.  

Fig. 3a shows the operation of the pseudo-random number sequences generator, which is present in both the remote control and the receiver device in the programming code representation. The two pseudo-random number sequence generators are loaded by a value which is derived from the code word displayed by the receiver unit and to be entered by the user in the remote control. If the correct code word is entered, both generators are initialized by the same numbers; they therefore generate the same encrypted word using f (GenReg). The data to be transmitted are encrypted by logical links using the code word and sent to the recipient side. There the data is decrypted using the same code word.

Fig. 3b shows the process of initializing the pseudo random sequence generator as it is present in both the remote control and the receiver. The registers are loaded with values derived from the code word. The two pseudo-random number sequence generators are thus initialized with the same values. Using f (GenReg, payload), the final code word is formed from this, which is then converted with the commands to be transmitted. The end result at the outputs shows the structure of the data to be transmitted with the encrypted IR command, the encryption flag and the n-bit overflow counter.

In the second exemplary embodiment, the code word is not generated in the receiver unit, but in the transmitter unit, that is to say in the remote control unit. Instead of using a pseudo-random number sequence generator, the code word is generated here as a function of previous commands, ie keyboard inputs in the remote control unit, ie from the "history" of the keyboard inputs of the remote control unit. Fig. 4 is a schematic of the generating and transmitting shows the code word to the receiver side. This process is triggered by operating an initialization button on the remote control. The code word is generated automatically according to the formula for F_Init_Code as a function of the keyboard inputs of the past. These keystrokes are recorded from time T0, at which the remote control is started, over time t. At the time T _init1 , when the start button for initiating the personalized mode is operated, the code word according to F_Init_Code (T _init1 ) is _generated from the "history" of the keyboard _entries in the period from T0 to the beginning of the initialization _phase , here T _init1 . The personalized mode is ended by pressing the start button again. This process is repeated for every further personalized operation at T _initN . As a result, the function F_Init_Code (T) for generating the code word has a kind of random characteristic. In this exemplary embodiment, the direct entry of the code word by means of the keyboard is therefore omitted. To record the commands of the past, the remote control has a memory that can be rewritten. In one variant, the memory cannot be volatile. Then command sequences from the past can also be recorded. Furthermore, the memory can be removed from the remote control. B. be implemented on a chip card. Otherwise, the mode of operation corresponds to that of the first exemplary embodiment with regard to the first and second operating modes.

In a modification of the first embodiment, this can also be done there the receiver unit automatically generates the codeword to the remote control be transmitted. For this purpose, the remote control with a receiving device provided that can record and recognize the code word. The transfer can here optically or again via an IR or other connection take place. Here too, the personalization mode is replaced by a corresponding command key on the remote control initiated and ended.

Instead of the keyboard, it can also be provided by softkeys, the inputs assigned to the keys appear on a display and can be selected there. The keyboard could also be controlled by a voice  Input system to be replaced or supplemented, in which spoken inputs converted into electrical information by means of a speech recognition system become.

Claims (33)

1. Communication method between a transmitter side and a receiver side, in particular where there is no wire, fiber or other fixed communication connection between the transmitter side and the receiver side, characterized by the following steps:

• - automatic generation of a code word on one of the pages,
• - transmission of the code word to the other side,
• Encryption of information using the code word on the transmitter side,
• - sending information from the transmitter side,
• - receiving information on the receiving end,
• - Decrypt the received information using the code word.

2. The method according to claim 1, characterized in that at predetermined Occasionally a new code word is generated. 3. The method according to claim 1 or 2, characterized in that the code word is generated by means of a random process. 4. The method according to any one of the preceding claims, characterized in that that the transmitted information contains control information.   5. The method according to any one of the preceding claims, characterized in that the information to be transmitted is encrypted depending on its type is sent using the code word or unencrypted. 6. The method according to any one of the preceding claims, characterized in to report to a third party whether encrypted or unencrypted is sent. 7. The method according to any one of the preceding claims, characterized in that that the generation of a code word is caused by a third party. 8. The method according to any one of the preceding claims, characterized in that that the transmitted code word is on the transmitter side by means of a character Giving device, in particular a keyboard is entered. 9. The method according to any one of the preceding claims, characterized in that that the code word can be made visible on the receiver side. 10. The method according to any one of the preceding claims, characterized in that that the code word can be made visible by the transmitter side. 11. The method according to any one of the preceding claims, characterized in that that the information via infrared, radio or ultrasound connection between between the sender side and the receiver side. 12. The method according to any one of the preceding claims, characterized in that information on the transmitter side is additionally according to a standard procedure  ren can be encrypted and that ver on the receiving end encrypted information can be decrypted. 13. The method according to any one of the preceding claims, characterized in that that button operations can be stored on the transmitter side. 14. The method according to claim 13, characterized in that the code word is generated on the transmitter side based on the key operations. 15. The method according to any one of the preceding claims, characterized in that the information sent contains control commands for the receiver side. 16. The method according to any one of the preceding claims, characterized in that it is used to remote control a consumer electronics device, in particular a digital decoder device is used. 17. Transmitter unit for communicating with a receiver side, comprising:

• Means for entering a code word transmitted by the recipient,
• Means for encrypting information using the code word,
• - Means for sending information.

18. Transmitter unit according to claim 17, characterized in that the code word input means by character input means, in particular by a Keyboard are realized.   19. Transmitter unit for communicating with a receiver side, comprising:

• Means for generating a code word,
• Means for transmitting the code word to the recipient side,
• Means for encrypting information using the code word,
• - Means for sending information.

20. Unit according to claim 19, characterized in that it character input means, in particular a keyboard. 21. Unit according to claim 20, characterized in that it has means for Storing entered characters. 22. Unit according to claim 21, characterized in that the storage means are removable from the unit. 23. Unit according to claim 21 or 22, characterized in that the code Word generating means are designed such that they on the code word Generate the base of previously entered characters. 24. Unit according to one of claims 17-23, characterized in that it additional means for encrypting information according to a standard dardverfahren has. 25. Receiver unit for communicating with a transmitter side, comprising:

• Means for generating a code word,
• Means for transmitting the code word to the transmitter side,
• Means for receiving information,
• - Means for decrypting information using the code word.

26. Unit according to claim 25, characterized in that the code word Generating means have a random generator. 27. Unit according to claim 25 or 26, characterized in that they additionally Lich means to decrypt information according to a standard is encrypted. 28. Unit according to one of claims 17-27, characterized in that the Information contains control commands. 29. Unit according to one of claims 17-28, characterized in that the Information contains control information. 30. Unit according to one of claims 17-29, characterized in that it Has means for making the code word visible. 31. Unit according to one of claims 17-30, characterized in that it Means for communicating via infrared, radio or ultrasound connection has, in particular transmitter or receiver units for transmitting or Receive infrared signals, radio signals or ultrasound signals.   32. Unit according to one of claims 17-31, characterized in that it for controlling a consumer electronics device, in particular a decoder device is configured. 33. Communication system with at least one transmitter unit according to one of the Claims 17-23 or 27-32 and at least one receiver unit according to one of claims 24-26 or 27-32.