Abstract: Some embodiments relate to a data processing method comprising selecting a key from a plurality of previously stored keys, depending on at least on predefined criterion relating to at least one current value of at least one given repository. Other embodiments relate to a reception method comprising receiving second data obtained by applying, to first obtained data, a first cryptographic function using a key selected from a plurality of previously stored keys, depending on at least one predefined criterion relating to a current value of at least one given repository and for obtaining the first data by applying, to the second received data, a second cryptographic function using a second key associated with the selected key. Further embodiments relate to a processing device and a reception device that respectively implement the processing method and the reception method.

Abstract: Some embodiments relate to a data processing method comprising selecting a key from a plurality of previously stored keys, depending on at least on predefined criterion relating to at least one current value of at least one given repository. Other embodiments relate to a reception method comprising receiving second data obtained by applying, to first obtained data, a first cryptographic function using a key selected from a plurality of previously stored keys, depending on at least one predefined criterion relating to a current value of at least one given repository and for obtaining the first data by applying, to the second received data, a second cryptographic function using a second key associated with the selected key. Further embodiments relate to a processing device and a reception device that respectively implement the processing method and the reception method.

Abstract: The present invention concerns a method of controlling the conformity of the transmission rate of data cells transmitted by a source terminal in communication with a destination terminal. It consists essentially, when a backward-resource management cell (BW-RM) of order k arrives at the said interface unit (21), of determining the programming time (tp(k)) of the taking into account, by the said control process (21b), of the rate request (ER(k)) contained in the field of the said cell (BW-RM). It also concerns a user-network interface unit which has means for being able to implement the steps of the said methods.