Enhance Multi-bit Spectral Analysis on Hiding in Temporal Dimension

Recent events have indicated that attackers are banking on side-channel attacks, such as differential power analysis (DPA) and correlation power analysis (CPA), to exploit information leaks from physical devices. Random dynamic voltage frequency scaling (RDVFS) has been proposed to prevent such attacks and has very little area, power, and performance overheads. But due to the one-to-one mapping present between voltage and frequency of DVFS voltage-frequency pairs, RDVFS cannot prevent power attacks. In this paper, we propose a novel countermeasure that uses reliable and aggressive designs to break this one-to-one mapping. Our experiments show that our technique significantly reduces the correlation for the actual key and also reduces the risk of power attacks by increasing the probability for incorrect keys to exhibit maximum correlation. Moreover, our scheme also enables systems to operate beyond the worst-case estimates to offer improved power and performance benefits. For the experiments conducted on AES S-box implemented using 45 nm CMOS technology, our approach has increased performance by 22 percent over the worst-case estimates. Also, it has decreased the correlation for the correct key by an order and has increased the probability by almost 3.5X times for wrong keys when compared with the original key to exhibit maximum correlation.

Side-channel attacks (SCAs) are powerful attacks that could be used to retrieve keys from electronic devices. Several physical leakage sources can be exploited in SCAs, such as power, time, heat, and so on. Heat is one of the side-channels that is not frequently analyzed by attackers in the literature due to the high noise associated with thermal traces. This article investigates the practicality of adapting power-based SCAs [i.e., correlation power analysis (CPA) and deep-learning-based power attacks (DL-based PA)] for thermal attacks and refer to them as correlation thermal attack (CTA) and DL-based thermal attack (DL-based TA). In addition, we introduce a new attack called progressive CTA (PCTA). We evaluate the different thermal SCAs against an unprotected and protected software implementation of Rivest–Shamir–Adleman (RSA). Our results show the practicality of the three attacks (i.e. CTA, DL-based TA, and PCTA) as a 100% key recovery is realized.

Side-channel attacks are nowadays a serious concern when implementing cryptographic algorithms. Powerful ways for gaining information about the secret key as well as various counter-measures against such attacks have been recently developed. Although it is well known that such attacks can exploit information leaked from different sources, most prior works have only addressed the problem of protecting a cryptographic device against a single type of attack. Consequently, there is very little knowledge on how a scheme for protecting a device against one type of side-channel attack may affect its vulnerability to other types of side-channel attacks. In this paper we focus on devices that include protection against fault injection attacks (using different error detection schemes) and explore whether the presence of such fault detection circuits affects the resistance against attacks based on power analysis. Using the AES S-Box as an example, we performed attacks on the unprotected implementation as well as modified implementations with parity check circuits or residue check circuits (mod3 and mod7). In particular, we focus on the question whether the knowledge of the presence of error detection circuitry in the cryptographic device can help an attacker who attempts to mount a power attack on the device. Our results show that the presence of error detection circuitry helps the attacker even if he is unaware of this circuitry, and that the benefit to the attacker increases with the number of check bits used for the purpose of error detection.

Many side-channel attacks on implementations of cryptographic algorithms have been developed in recent years demonstrating the ease of extracting the secret key. In response, various schemes to protect cryptographic devices against such attacks have been devised and some implemented in practice. Almost all of these protection schemes target an individual side-channel attack and consequently, it is not obvious whether a scheme for protecting the device against one type of side- channel attacks may make the device more vulnerable to another type of side-channel attacks. We examine in this paper the possibility of such a negative impact for the case where fault detection circuitry is added to a device (to protect it against fault injection attacks) and analyze the resistance of the modified device to power attacks. To simplify the analysis we focus on only one component in the cryptographic device (namely, the S-box in the AES and Kasumi ciphers), and perform power attacks on the original implementation and on a modified implementation with an added parity check circuit. Our results show that the presence of the parity check circuitry has a negative impact on the resistance of the device to power analysis attacks.

SUMMARY Recently, side-channel attacks have become a serious problem. These attacks estimate the secret keys of cryptography circuits embedded in hardware. In particular, the most threatening side-channel attacks are differential power analysis and correlation power analysis, which use the correlation between information processing and power consumption, which are related to secret keys in cryptography circuits. Therefore, new measures are required to prevent confidential information in cryptography circuits from being leaked to side-channel information, such as power consumption. When designing preventive measures, resistance to side-channel attacks, for instance tamper resistance, must be evaluated. This study proposes a new simulation method by which tamper resistance can be verified in the algorithm and architecture design phases. Experimental results show the validity of the proposed simulation method. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(2): 40–51, 2014; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22342

The Correlation Power Analysis (CPA) is used to compromise the security of crypto systems by measuring and analyzing physical leakage that is the power consumption. Unlike classical cryptanalysis techniques, it requires very less computations to extract the secret information of the cipher systems. But, one of the main hindrances in mounting the CPA attack is the segregation of single power trace of multiple encryptions performed continuously (without pause) among number of traces corresponding to individual encryptions. To overcome this limitation, a new technique is proposed in this paper to split the power traces of AES and DES algorithms running continuously on FPGA. This (energy of samples based algorithm) finds the start of the encryption and computes number of samples in each clock of FPGA. It exploits the repetition of specific patterns available in the traces to determine the encryption length in terms of number of samples. With this information, it splits a power trace of several consecutive encryptions among number of traces corresponding to each encryption. The important thing is that it does not require information about clock frequency of FPGA board and sampling rate of the Oscilloscope. This algorithm was applied on the traces of 25, 50, 100, 125 and 250 samples per clock (when processing was performed at 1, 2 & 4 MHz clock frequencies). In all the cases, the key of AES and DES were retrieved by mounting the CPA attack on splitted traces resulting from the splitting technique.

In this article, we present a compact implementation of the Salsa20 stream cipher that is targeted towards lightweight cryptographic devices such as radio-frequency identification (RFID) tags. The Salsa20 stream cipher, ann addition-rotation-XOR (ARX) cipher, is used for high-security cryptography in NEON instruction sets embedded in ARM Cortex A8 CPU core-based tablets and smartphones. The existing literature shows that although classical cryptanalysis has been effective on reduced rounds of Salsa20, the stream cipher is immune to software side-channel attacks such as branch timing and cache timing attacks. To the best of our knowledge, this work is the first to perform hardware power analysis attacks, where we evaluate the resistance of all eight keywords in the proposed compact implementation of Salsa20. Our technique targets the three subrounds of the first round of the implemented Salsa20. The correlation power analysis (CPA) attack has an attack complexity of 2 19 . Based on extensive experiments on a compact implementation of Salsa20, we demonstrate that all these keywords can be recovered within 20,000 queries on Salsa20. The attacks show a varying resilience of the key words against CPA that has not yet been observed in any stream or block cipher in the present literature. This makes the architecture of this stream cipher interesting from the side-channel analysis perspective. Also, we propose a lightweight countermeasure that mitigates the leakage in the power traces as shown in the results of Welch’s t -test statistics. The hardware area overhead of the proposed countermeasure is only 14% and is designed with compact implementation in mind.

Cryptographic devices are vulnerable to the nowadays well known side channel leakage analysis. Secret data can be revealed by power analysis attacks such as Simple Power Analysis (SPA), Differential Power Analysis (DPA) and Correlation Power Analysis (CPA). First, we give an overview of DPA in mono-bit and multi-bit cases. Next, the existing multi-bit DPA methods are generalized into the proposed Partitioning Power Analysis (PPA) method. Finally, we focus on the CPA technique, showing that this attack is a case of PPA with special coefficients and a normalization factor. We also propose a method that allows us to improve the performance of CPA by restricting the normalization factor.Keywordsside channelpower analysisDPAmulti-bit DPAPPACPAcorrelationDESAES

Correlation Power Analysis (CPA) introduced by Brier et al. in 2004 is an important method in the side-channel attack and it enables the attacker to use less cost to derive secret or private keys with efficiency over the last decade. In this paper, we propose R-squared fitting model analysis (RFA) which is more appropriate for nonlinear correlation analysis. This model can also be applied to other side-channel methods such as second-order CPA and collision-correlation power attack. Our experiments show that the RFA-based attacks bring significant advantages in both time complexity and success rate.

Side-channel attacks have recently become one of primary threats that target modern computing devices. Several techniques have been proposed to improve the strength of side-channel attacks. Preprocessing is one of those techniques that improves the side-channel attacks by processing the measured leakage traces before performing the statistical analysis. The advantages of preprocessing techniques can potentially increase the performance and precision of side-channel attacks. Preprocessing of the measured leakage typically leads to faster side-channel attacks that require less number of measurements. A novel combined attack which utilizes the preprocessing techniques effectively is proposed in this work. Mutual information analysis (MIA) and correlation power analysis (CPA) are implemented for the preprocessing and attack steps interchangeably. For the first time, a combined attack is performed on a lightweight Prince cipher. The proposed preprocessing technique is demonstrated to reduce the required number of measurements to disclose a secret key by up to 25%.

Correlation Power Analysis (CPA) is one of effective means of power analysis in side channel analysis. The noisy power traces can affect the power of CPA. It is significant to select the helpful power traces to improve the efficiency of analysis. In this paper, we present a new pre-processing method that is based on Improved Singular Value Decomposition (ISVD) for selecting the traces when using CPA to attack. The ISVD is a combination of SVD and Z-score. Experimental results show that our method is effective to improve the efficiency when analyzing both the unprotected implementation and the masked implementation.

Cryptographic System-on-Chips (SoCs) are becoming more and more popular. In these systems, cryptographic accelerators are integrated with processor cores to provide users with the software’s flexibility and hardware’s high performance. First, this work aimed to confirm the vulnerability of cryptographic SoCs against several types of power analysis attacks. Then, the novel Random Dynamic Frequency Scaling (RDFS) countermeasure is proposed to improve the resistance of such systems. The proposed RDFS countermeasure improved the power analysis resistance while maintaining low-performance overhead and hardware costs by generating more than 219,000 distinct frequencies for driving only the cryptographic accelerators. The effectiveness of the proposed RDFS countermeasure is demonstrated by conducting realistic Correlation Power Analysis (CPA) attacks, Deep-Learning-based Side-Channel Analysis (DL-SCA) attacks, and Test Vector Leakage Assessment (TVLA) testing methodology. The experimental results show that the RISC-V SoC protected by RDFS countermeasure can withstand CPA attacks and TVLA test with more than five million power traces, which is the best result compared to other related works. The proposed RDFS countermeasure also harden the targeted RISC-V SoC’s resistance against DL-SCA attacks.

Emerging technologies such as Spin-transfer torque magnetic random-access memory (STT-MRAM) are considered potential candidates for implementing low-power, high density storage systems. The vulnerability of such nonvolatile memory (NVM) based cryptosystems to standard side-channel attacks must be thoroughly assessed before deploying them in practice. In this paper, we outline a generic Correlation Power Analysis (CPA) attack strategy against STT-MRAM based cryptographic designs using a new power model. In our proposed attack methodology, an adversary exploits the power consumption patterns during the write operation of an STT-MRAM based cryptographic implementation to successfully retrieve the secret key. In order to validate our proposed attack technique, we mounted a CPA attack on MICKEY-128 2.0 stream cipher design consisting of STT-MRAM cells with Magnetic Tunnel Junctions (MTJs) as storage elements. The results of the experiments show that the STT-MRAM based implementation of the cipher circuit is susceptible to standard differential power analysis attack strategy provided a suitable hypothetical power model (such as the one proposed in this paper) is selected. In addition, we also investigated the effectiveness of state-of-the-art side-channel attack countermeasures for MRAMs and found that our proposed scheme is able to break such protected implementations as well.

In this paper, we propose a novel cell-level side channel countermeasure fluctuating power logic (FPL), which diffuses the correlation between the real power consumption and the fixed data transitions by employing a cascade voltage logic. The countermeasure further acts as a cell-level V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DD</inf> randomizer, making it a strong candidate for implementing algorithmic countermeasure and exploiting its noise generation capabilities. This proposed scheme is illustrated by a standard flip-flop. HSPICE based simulation results show that the modified flip-flop is resistant against power analysis at the cost of doubled power dissipation. Two illustrative case studies of PRESENT and AES substitutions have been explored. The resistance against Side-Channel Analysis(SCA) is evaluated by the correlation power analysis. The new logic outperforms other counterparts in consideration of both security and cost, which renders it as a practical solution for resource-constrained systems. The proposed cell-level countermeasure can naturally mitigate other SCA such as electromagnetic analysis.

We evaluate the vulnerability of a pipelined Advanced Encryption Standard (AES) against Correlation Power Analysis (CPA) Side-Channel Attack (SCA). We identify that the registers in pipelined AES are most vulnerable against CPA SCA and propose a new power model targeting the switching activities of the registers. The proposed power model is constructed based on the Hamming Distance (HD) between the intermediate values stored in the registers in two consecutive clock cycles. Then, we analyze the vulnerability of pipelined AES under two scenarios. First, during regular pipeline operation where the device is performing AES pipeline operation. Second, in non-pipeline operation where we assume the adversaries can insert delay to the input of the device to increase the signal to noise ratio of the physical leakage information. The simulation results show that under regular pipelined operation, our proposed power model can reveal all the 16 key bytes in less than 4,900 traces, resulting in 4.7× more effective than the conventional power models. Under non-pipelined operation, our proposed power model requires only 590 traces to reveal all the 16 key bytes, which is 5.9× more effective than other power models.