Patent ID: 9087219
Filing Date: 2015-07-21
Classification: G06F

Abstract:
1. A circuit adapted to be operated in a plurality of modes of operation, wherein each mode of operation has associated therewith a specific valid state, comprising: a storage location adapted to store a number of states, which is larger than a number of valid states necessary to address the plurality of modes of operation, wherein the circuit is configured to be operated in one of the plurality of modes of operation depending on the state acquired by the storage location, wherein the circuit is adapted to switch to the mode of operation associated with a specific valid state when the storage location acquires this specific valid state, and wherein the circuit is adapted to compare a value read out from the storage location to a list of values corresponding to the valid states and to switch to a predetermined one of the plurality of modes of operation when the value read out from the storage location is not comprised in the list of values, wherein the circuit is adapted such that a security level or a level of resistance with respect to attacks on the circuit is higher for the predetermined mode of operation than for another mode of operation, and wherein a) the circuit is adapted to process or transfer data to an external component, wherein the data is masked by a changeable mask during processing or transferring, or wherein the data is blinded based on a changeable key, wherein the different modes of operation differ with respect to at least one of a frequency of mask changes and key changes or with respect to at least one of a mask length and a key length, wherein the circuit is adapted such that the predetermined mode of operation corresponds to the highest frequency or the longest key; b) wherein the circuit is adapted such that the different modes of operation comprise different correlations of power consumption and processed data, and such that the predetermined mode of operation comprises the lowest level of correlation; or c) wherein the circuit comprises a true random number generator and a pseudo random number generator, wherein the circuit is adapted such that the true random number generator is used for initializing the pseudo random number generator, and wherein the circuit is adapted such that the different modes of operation correspond to different frequencies of the initialization of the pseudo random number generator, and wherein the predetermined mode of operation is that with the highest number of initializations.