Abstract: A method and system for testing the cryptographic integrity of data m comprises at least the following elements: a module transmitting a message M, said module comprising a memory for storing the parameters used to execute the steps of the method, such as the key, the public data, a transmission medium, a receiver module also comprising storage means for storing at least the same parameters as in transmission. The system may comprise storage means for storing confidential data such as the secret keys, a processor suitable for executing the steps.

Abstract: A method for generating cryptographic half-keys makes it possible to generate n pairs (Ki1, Ki2), 1?i?n, of cryptographic half-keys, each of said pairs making it possible to reconstruct an access key KPL specific to a secure apparatus, said method comprising at least the following steps: generating and storing, with the help of a management center distinct from said apparatus, a first series of n half-keys Ki1 on a recording medium; supplying the apparatus with said recording medium so as to generate, with the help of said local key KPL and of the n half-keys Ki1 stored on said medium, a second series of n half-keys Ki2 making it possible to form said n pairs (Ki1, Ki2). The method applies notably to the creation of several keys for access to a secure apparatus.

Abstract: A method and system for testing the cryptographic integrity of data m comprises at least the following elements: a module transmitting a message M, said module comprising a memory for storing the parameters used to execute the steps of the method, such as the key, the public data, a transmission medium, a receiver module also comprising storage means for storing at least the same parameters as in transmission. The system may comprise storage means for storing confidential data such as the secret keys, a processor suitable for executing the steps.

Abstract: A method for generating cryptographic half-keys makes it possible to generate n pairs (Ki1, Ki2), 1?i?n, of cryptographic half-keys, each of said pairs making it possible to reconstruct an access key KPL specific to a secure apparatus, said method comprising at least the following steps: generating and storing, with the help of a management center distinct from said apparatus, a first series of n half-keys Ki1 on a recording medium; supplying the apparatus with said recording medium so as to generate, with the help of said local key KPL and of the n half-keys Ki1 stored on said medium, a second series of n half-keys Ki2 making it possible to form said n pairs (Ki1, Ki2). The method applies notably to the creation of several keys for access to a secure apparatus.

Abstract: Method and system are disclosed for managing erratic interruptions in a transmission system where the messages to be transmitted are composed of data packets and are expressed by means of a polynomial of degree t?1. The senders and the receivers share information making it possible to reference the data packets. In the course of the transmission of a message represented by a polynomial P, at least t points Ai are generated and P(Ai) of the polynomial P is evaluated, with t? greater than or equal to t. The evaluations P(Ai) are transmitted of the t? points to the receiver or receivers concerned, with information allowing the receivers to detect the transmission errors.

Abstract: Method for generating pseudo-random bit strings in a system in which the data interchanges between a first user and a second user are protected, characterized in that it comprises at least the following steps: using an application fk of output size n bits, determining a value x and, from this value x and by applying the application fk, generating t values vi, from the t values vi and, from u*t coefficients, determining u blocks Si containing pseudo-random characters. Applicable to the coding or authentication domain.

Abstract: Method and system are disclosed for managing erratic interruptions in a transmission system where the messages to be transmitted are composed of data packets and are expressed by means of a polynomial of degree t?1. The senders and the receivers share information making it possible to reference the data packets. In the course of the transmission of a message represented by a polynomial P, at least t points Ai are generated and P(Ai) of the polynomial P is evaluated, with t? greater than or equal to t. The evaluations P(Ai) are transmitted of the t? points to the receiver or receivers concerned, with information allowing the receivers to detect the transmission errors.

Abstract: A method is disclosed for the transmission of information. The information contains n information carrier cells, with n being greater than or equal to 2. The method of linear encoding for erratic transmission includes at least the following steps: generating a mask {Mi}i=l,n of n cells corresponding to n information carrier cells; making a linear combination of at least all the n cells with the n cells of the generated mask to obtain a resulting word; performing a linear operation on the n cells of the resulting word to obtain a cell BT,j to be transmitted.

Abstract: A method is disclosed for the transmission of information. The information contains n information carrier cells, with n being greater than or equal to 2. The method of linear encoding for erratic transmission includes at least the following steps: generating a mask {Mi}i=1,n cells corresponding to n information carrier cells; making a linear combination of at least all the n cells with the n cells of the generated mask to obtain a resulting word; performing a linear operation on the n cells of the resulting word to obtain a cell BT,j to be transmitted.