Abstract: A secure system-on-chip for processing data comprises at least a central processing unit, an input and an output channel, an encryption/decryption engine and a memory, wherein said input channel comprises an input encryption module to encrypt all incoming data, said output channel comprises an output decryption module to decrypt all outgoing data, said central processing unit receiving the encrypted data from the input encryption module and storing them in the memory, and while processing the stored data, said central processing unit reading the stored data from the memory, requesting decryption of same in the encryption/decryption engine, processing the data and requesting encryption of the result by the encryption/decryption engine and storing the encrypted result, outputting the result to the output decryption module for decryption purposes and outputting the decrypted result via the output channel.

Abstract: The aim of the present invention is to propose a method and a device in order to avoid damages that the desynchronisation of the program counter may cause. This aim is achieved by means of a secured microprocessor comprising a program counter and an interface with a program memory containing the instructions, this microprocessor being wherein it includes a historical memory of the program counter indicating the position of the program counter at the time of the execution of the previous instruction, and an instruction verification module, this module comprising reading means of an additional piece of verification information that defines for the instruction in progress, the supposed position of the previous program counter, this verification module comprising means to compare this verification information with that originating from the historical memory and means to generate an error if the verification indicates an incompatibility.

Abstract: The aim of this invention is to propose a flexible solution to the risk represented by access to a temporary memory of a specialized decryption/decompression circuit for a Pay-TV decoder.

Abstract: The aim of this invention is to improve in an optimal way the security of smart cards to prevent the fraudulent control of a cryptographic processor(s) by means of external signals that interfere with the normal development of the tasks of a processor(s).

Abstract: At the moment of the diffusion of Pay-TV with multi-channel signals, each channel is associated to authorization messages (ECM) which allow to decrypt this channel according to the rights of the subscriber. When changing channel, a very short time is accepted before one has determined these new rights in relation with the new channel. The heavy encrypting algorithms are thus excluded. To avoid this drawback, to decrypt a channel, a system is proposed using the combination of the authorization information for a channel (ECM), and thus encrypted by a fast algorithm, with authorization information (MECM) for a group of channels. These latter are encrypted by a high security algorithm and are thus slower to decrypt.

Abstract: System for controlling the transmission of information between a receiver and a security module, especially for a pay television system, in which the transmitted information is encrypted and decrypted by means of a unique encryption key stored, on the one hand, in the receiver and, on the other hand, in the security module.

Abstract: A data processing system comprises a set of memory cards (10) and at least one central administration and processing unit (22). According to the invention, the memory cards and the processing unit together form a relational database. Each memory card contains a memory (28) for storing a set of instructions (A1, A2, . . . , An), each instruction containing a logical link with at least one other instruction. The system is applicable notably to pay-TV and other restricted access systems, for example in banking.

Abstract: A scrambling method wherein each image line (23-309) of a frame having been produced in unscrambled form before being scrambled, is given the pseudorandomly determined address (B) of the memory line in the storage memory (8) in which said image line is to be stored on reception; and wherein the moment (or the running order) for broadcasting said image line is determined so that on reception, the image line causes, because it is stored in the memory line to which it was addressed, the image line previously stored at the same address to be output to the television set at the right moment (or in the right order) so that an unscrambled picture is reconstructed.

Abstract: A decoder comprising a microprocessor connected to a receiver of data of teletext and to a text generator for displaying information on the screen of a television receiver. Further, a CPTV-card (card pay-television) is associated with the microprocessor, this card managing the credit necessary for the purchase of emissions, for the memorization of the emissions purchased and for permitting the unscrambling of the emissions purchased by delivering to the microprocessor the input pointer in the sequence which is calculated by the microprocessor by means of the information which has been memorized as well as the information delivered by the decoder. The programs of the forecasted emissions are transmitted by the head station and memorized in the microprocessor of the decoder. Another memory of the microprocessor contains the instructions for the manipulations to be effected for selecting an emission and for purchasing it as well as for recharging a credit in the CPTV-card.

Abstract: According to the invention, on the emitter side, a number generator (10) delivers a random code (XAL) which is sent to the input of a master card (11) which ciphers such code according to a predetermined key (100), the code thus ciphered is broadcast with the video signal, a first device (17) receives, on the one hand, the random code (XA) and, on the other hand, the code ciphered by the master card (11) and effects a predetermined numerical combination of these two codes, such combination forming the initialization word of a pseudo-random generator (12) intended to provide a table of codes for scrambling the video signal and, on the receiver side, the ciphered code received is deciphered by a customer card (13), a second device (18) receives at the inputs, on the one hand, the ciphered code and, on the other hand, the code deciphered (XA) by the customer card (13) and effects a numerical combination of these two codes which is similar to the combination of the first device (17).