Patent ID: 6961429
Filing Date: 2005-11-01
Classification: H04L

Abstract:
1. Method to check the integrity and the authenticity of a data set received by a pay television decoding unit including a decoder, a security unit, and means of communication with a control center, comprising a first step of calculation by said decoding unit of a check information which is representative of the result of a unidirectional and collision-free function, carried out on all or part of the data set, said method comprising further steps of: transmitting the check information by said decoding unit to the security unit and ciphering said check information with a first cipher-key, sending the ciphered check information to the control center, deciphering of the ciphered check information by the control center and comparison with a reference value of the check information, transmitting control data including the result of the comparison in a ciphered form to the security unit, deciphering of the ciphered result of the comparison by the security unit and informing the decoder of the validity of the data set.