Abstract: A method of protecting a telecommunication terminal having a chip-card-type personal component which is required for telecommunication network access. The terminal includes a processing unit, at least one operating memory element containing the information necessary to the operation of the terminal, i.e. a terminal operating program, and the data necessary to the program. The method involves: a) encrypting the contents of the operating memory element of the telecommunication terminal using a pre-determined key K which is necessary for decryption; and b) allowing the terminal to commence decryption once the terminal has been started with a start-up program that is saved in a secure memory element and once the key for decryption has been calculated by same.

Abstract: The invention relates to a method for secure data transmission in connections between two functional modules of an electronic unit. A first module of a message of k bits in a word code of n bits is injection coded with a constant Hamming weight of w. The word of code is transmitted to a second module. An error signal is generated when the Hamming weight of the word of code of n bits, received by the second module, is different from w. In the absence of error, the code word is decoded, where k, w and n are whole numbers. The invention further relates to a corresponding electronic circuit.

Abstract: Access control to data processing means, such as a smart card, is made secure by simulating a comparison block by block of part of a secret code with part of a presented code through a block-by-block comparison of part of the presented code and part of a determined number when the presented code is found to be erroneous. Each time the card is used, a constant number of operations are applied to the presented code and at least for part of the secret code, and at most for a complementary part to the determined number, thus avoiding different signatures of power consumption for different presented codes.

Abstract: A method of protecting a telecommunication terminal having a chip-card-type personal component which is required for telecommunication network access. The terminal includes a processing unit, at least one operating memory element containing the information necessary to the operation of the terminal, i.e. a terminal operating program, and the data necessary to the program. The method involves: a) encrypting the contents of the operating memory element of the telecommunication terminal using a pre-determined key K which is necessary for decryption; and b) allowing the terminal to commence decryption once the terminal has been started with a start-up program that is saved in a secure memory element and once the key for decryption has been calculated by same.

Abstract: The invention relates to a method for secure data transmission in connections between two functional modules of an electronic unit. A first module of a message of k bits in a word code of n bits is injection coded with a constant Hamming weight of w. The word of code is transmitted to a second module. An error signal is generated when the Hamming weight of the word of code of n bits, received by the second module, is different from w. In the absence of error, the code word is decoded, where k, w and n are whole numbers. The invention further relates to a corresponding electronic circuit.

Abstract: The invention constitutes an improvement of access control security to data processing means, such as a smart card (MNV, MA), by simulating a comparison (E7) block by block (Si, Pi) of part of a secret code (S) with part of the presented code (P) through a block-by-block comparison (Pi, Aj) of part of the presented code and part of a number (A) when the presented code is found to be erroneous. Each time the card is used, a constant number of operations are applied to the presented code (P) and at least for part of the secret code (S) and at most for a complementary part relative to the number of operations, to the number (A), thus avoiding different signatures of power consumption for different presented codes.