Patent ID: 7440571

Claim:
A method for securing updating data from a plurality of apparatuses, each apparatus receiving the updates from a managing center, the updates including patch data accompanied by a control message encrypted by a private asymmetrical key taken from a list of keys included in the managing center, the method comprising the steps of: (a) selecting by the apparatus of a current public key from a list of public keys stored in a non-volatile memory of the apparatus; (b) receiving and storing the patch data in a random access memory; (c) receiving the encrypted control message; (d) decrypting the encrypted control message using the selected current public key; (e) verifying that the decrypted control message corresponds to said patch data; (f) installing the patch data; (g) deactivating the current public key such that a different public key is used to decrypt a next control message; and (h) repeating steps a-g for a subsequent patch data and encrypted control message using a subsequent public key selected by the apparatus from the list of public keys stored in the non-volatile memory, the subsequent public key being different from the current public key deactivated in step (g).