Patent ID: 8160248
Filing Date: 2012-04-17
Classification: G06F,H04L

Abstract:
1. A controlled device operable in a plurality of modes, the controlled device comprising: (a) at least one processor configured to receive a requested mode value and an encrypted secret key, wherein the requested mode value corresponds to one of the plurality of modes; (b) a non-volatile memory configured to hold at least one global root key; (c) a key deriver coupled to the non-volatile memory, comprising a plurality of key derivation functions, wherein each key derivation function of the plurality of key derivation functions includes an assigned mode value corresponding to one of the plurality of modes, and wherein said each key derivation function is configured to take as input the at least one global root key and produce a root key specific to the assigned mode value; (d) a key manager coupled to the key deriver and to the at least one processor, and configured to use the root key to decrypt the encrypted secret key to recover a secret key.