Method for protecting a cryptographic module and a device having cryptographic module protection capabilities

Abstract

A device and a method for protecting a cryptographic module of which the method includes: estimating a functionality of a circuit that is adapted to malfunction when a physical parameter has a first value different from a nominal parameter value at which the cryptographic module functions correctly. The cryptographic module malfunctions when the physical parameter has a second value different from the nominal parameter value and a difference between the first value and the nominal parameter value being smaller than a difference between the second value and the nominal parameter value. A cryptographic module protective measure is applied if estimating that the circuit malfunctions.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a method for protecting a cryptographic module and a device having cryptographic module protection capabilities.BACKGROUND OF THE INVENTION[0002]Modern mobile and stationary devices apply security measures for various purposes. These security measures can include encrypting or decrypting information. A module (otherwise known as a cryptographic module) can execute these security measures. A cryptographic module can include hardware, software, firmware, or a combination thereof. The cryptographic module is expected to encrypt (or decrypt) information using one or more encryption keys. Typically, a sequence of input signals (an input vector) is encrypted by a cryptographic key to provide an encrypted output (an output vector).[0003]A cryptographic module is usually subjected to various types of attacks. These attacks are aimed to detect how the cryptographic module works and especially to determine the value of an encryption...

AI Technical Summary

Problems solved by technology

Hardware faults can increase a cipher's vulnerability to cryptanalysis.

Faults can be induced by various manners, including but not limited to subjecting the device to abnormal conditions (high temperature, very low temperatures, supplying a supply voltage level that does not correspond to the frequency of clock signal that is provided to the device, and the like).

Accordingly, an erasure of the stored key (e.g. stored in the cryptographic module) will not necessarily protect the key as the output already contains key related information.