Method to secure the reception of a broadcast content encrypted by at least one transmission key and transmitted to at least one decoding unit, said at least one transmission key being generated and transmitted by a control center, said decoding unit having at least one environment parameter known by the control center, said method comprising the following steps: - receiving by the decoding unit from the control center a first message common to a plurality of decoding units comprising the encrypted transmission key k, - receiving by the decoding unit from the control center a second message pertaining to said decoding unit comprising correction data, said correction data is calculated by the control center based on at least one environment parameter of the decoding unit, said environment parameter being specific to said decoding unit or a group of decoding units, the environment parameter being: - a software version of said decoding unit, - configuration data of hardware module, - status information of hardware module, - a certificate, - a hash function of all or part of the software, - a location indication of the decoding unit, - a hardware address of a local network interface, or - an identification number of one of the hardware devices of said decoding unit said first or second message further comprising an indication of which environment parameter to be used, - determining by the decoding unit the at least one environment parameter of the decoding unit by using the indication contained in the first or second message, - decrypting the encrypted transmission key k using the determined environment parameter and the correction data. - receiving by the decoding unit from the control center a first message common to a plurality of decoding units comprising the encrypted transmission key k, - receiving by the decoding unit from the control center a second message pertaining to said decoding unit comprising correction data, said correction data is calculated by the control center based on at least one environment parameter of the decoding unit, said environment parameter being specific to said decoding unit or a group of decoding units, the environment parameter being: - a software version of said decoding unit, - configuration data of hardware module, - status information of hardware module, - a certificate, - a hash function of all or part of the software, - a location indication of the decoding unit, - a hardware address of a local network interface, or - an identification number of one of the hardware devices of said decoding unit said first or second message further comprising an indication of which environment parameter to be used, - a software version of said decoding unit, - configuration data of hardware module, - status information of hardware module, - a certificate, - a hash function of all or part of the software, - a location indication of the decoding unit, - a hardware address of a local network interface, or - an identification number of one of the hardware devices of said decoding unit - determining by the decoding unit the at least one environment parameter of the decoding unit by using the indication contained in the first or second message, - decrypting the encrypted transmission key k using the determined environment parameter and the correction data.