Current Balancing Random Body Bias in FDSOI Cryptosystems as a Countermeasure to Leakage Power Analysis Attacks

Abstract

This paper identifies vulnerabilities to recently proposed countermeasures to leakage power analysis attacks in FDSOI systems based on the application of a random body bias. The vulnerabilities are analyzed and the relative difficulty to obtain the secret key, once the vulnerabilities are taken into account, are compared to the original proposals. A new countermeasure, based on a new body bias scheme, is then proposed. The new countermeasure is based on the equalization of asymmetries in static power consumption dependent on data being stored in registers implemented in FDSOI technology. The countermeasure's effectiveness is theoretically established through the development of a power model based on technological parameters, and further reinforced through numerical simulations of a dummy cryptosystem implementing part of an AES encrypting round.INDEX TERMS Body bias, correlation power analysis, countermeasures, cryptography, FDSOI, leakage power analysis, side-channel. I. INTRODUCTIONThe exploitation of power consumption of cryptographic circuits as a source of information and a means to retrieve the secret key has been extensively studied in the last two decades [1]. These so called Power Analysis Attacks (PAA) rely on asymmetries in power consumption that arise from differing circuit states subjected to the data being processed in intermediate stages of encrypting algorithms.Traditionally, PAA have mainly focused on the dynamic power consumption of cryptographic circuits to derive statistical models of power consumption based on the data being processed. These models of power consumption allow the testing of secret key hypothesis with a minimum setting and quick computation.PAA traditionally rely on statistical metrics, namely, the Difference of Means or the Pearson Correlation Coefficient (PCC) [2], to test secret key hypothesis given a correct power model. Since power consumption is dependent on processed data which is, in turn, dependent on the secret key, the power consumed by a cryptographic circuit is highly correlated withThe associate editor coordinating the review of this manuscript and approving it for publication was Junggab Son .