Examining smart-card security under the threat of power analysis attacks

Abstract

ÐThis paper examines how monitoring power consumption signals might breach smart-card security. Both simple power analysis and differential power analysis attacks are investigated. The theory behind these attacks is reviewed. Then, we concentrate on showing how power analysis theory can be applied to attack an actual smart card. We examine the noise characteristics of the power signals and develop an approach to model the signal-to-noise ratio (SNR). We show how this SNR can be significantly improved using a multiple-bit attack. Experimental results against a smart-card implementation of the Data Encryption Standard demonstrate the effectiveness of our multiple-bit attack. Potential countermeasures to these attacks are also discussed.

On Second-Order Differential Power Analysis

“…Firstly, SNR is independent of ; this corresponds to the results found in, e.g., [13], where SNR is also independent of if there is no (non-algorithmic) noise. Secondly, SNR drops off to 0 quickly as n gets larger, which was also observed in [13].…”

“…Firstly, SNR is independent of ; this corresponds to the results found in, e.g., [13], where SNR is also independent of if there is no (non-algorithmic) noise. Secondly, SNR drops off to 0 quickly as n gets larger, which was also observed in [13]. Finally, however, by evaluating SNR for fixed values of n, n ≥ 3, searching for the optimal value of α we have found that SNR is maximized consistently at α = 3, where SNR at α = 3 is about 1.55 times higher than at α = 1.…”

“…More surprisingly, for α = 2, the height of the DPA peaks does not depend on n, and for larger values of α (two last columns in Table 1) the height increases with the value of n. The results listed in Table 1 are useful for practical purposes assuming that sufficiently many acquisitions are available. To see how fast D 2 (α) actually converges to its expected value as a function of α, we determine the relevant signalto-noise ratio (SNR), following, e.g., [13]. In the present paper, we are concerned with so-called algorithmic noise only, so the value of SNR tells us how many traces we need (for different values of input data x) to get a successful DPA attack.…”

Cryptanalysis of an Improved Smartcard-based Remote Password Authentication Scheme

“…In addition, Wang et al's scheme is not easily repairable and is unable to provide perfect forward secrecy of the generated session key. Other instances of vulnerabilities in published smartcard-based password authentication schemes include off-line password guessing attack [6][7][8]22], impersonation attack [9][10][11], forgery attack [4,[12][13][14], DoS attack [4,7,18,23], parallel session attack [4,9,10,18], replay attack [23], stolen/lost smartcard attack [9,22,24], observing power consumption [25] and reverse engineering techniques [26,27].…”

Improved Higher-Order Side-Channel Attacks with FPGA Experiments

“…Although less general than classical cryptanalysis, because they usually target one specific implementation, they have been particularly efficient to break a wide variety of devices, including smart cards, ASICs and FPGAs [12,16,20]. As a straightforward consequence, countermeasures against these attacks are of great practical interest.…”