Countermeasure techniques for SEED hardware modules against differential power analysis

On two DES implementations secure against differential power analysis in smart-cards

In recent years, power analysis attacks have caused increasingly serious security threats on cryptographicalgorithm, to solve this problem different researcher has put forward many solutions, and among them the fixed value masking technology is one of the mostly used due to its lower cost and faster speed. Both theoretical and practical results have shown that the masking method has a good resistance to differential power analysis (DPA) attack. So based on the in-depth study of fixed masking technology, this paper proposed a second order DPA attack (SODPA) with the help of a pre-processing treatment. In the end, we implemented this attack on a fixed value masked AES encryption algorithm running in Mega16. The experimental result shows that, if the mask value is unknown, ordinary DPA cannot recover the right key, while the second order DPA only needs about 500 power curves to get the correct key. In the meantime, the differences between right and wrong keys are very obvious, which strongly proved the validity and practicability of our method.

Side channel analysis(SCA) focuses on attacking cryptographic algorithm implementations by collecting leaked information and analyzing the correlation between the leaked and key information in the cryptographic system. Currently, SCA is the main threat to cryptographic implementations, with DPA (differential power analysis) and DFA (differential fault analysis) being two of the most threatening types of SCA. However, the existing countermeasures against DPA and DFA have shortcomings and can hardly protect cipher designs perfectly. Based on a comprehensive analysis of DPA and DFA, this paper proposes a new idea of using an evolutionary cipher (EVOC) against DPAs based on the model proposed by Kocher, and several different new types of DFAs. In fact, an EVOC is a kind of dynamic cipher designing method. Moreover, combined with intelligent searching algorithms and cryptography design policies, EVOCs utilize the dynamic and unpredictable properties of TRNG (a truly random number generator) to ensure cipher design at a high level of security. Therefore, with an EVOC we could design cryptography algorithms with high security to resist mathematical analysis as well as DPAs and DFAs. This paper analyzes and proves the security, efficiency, cost, and original features of EVOCs against DPA and DFA both theoretically and experimentally. Compared with existing countermeasures against SCAs, EVOCs use dynamic non-linear operations to destroy the bases of DPA and DFA. At the algorithm level, EVOCs are more efficient than other resistance methods. Based on the theory and experiments, this paper proposes certain modifications to the EVOC in the AES (advanced encryption standard) algorithm, which can be referenced by other dynamic designs of cryptographic algorithms.

In order to protect a cryptographic algorithm against Power Analysis attacks, a well-known method consists in hiding all the internal data with randomly chosen masks.Following this idea, an AES implementation can be protected against Differential Power Analysis (DPA) by the “Transformed Masking Method”, proposed by Akkar and Giraud at CHES’2001, requiring two distinct masks. At CHES’2002, Trichina, De Seta and Germani suggested the use of a single mask to improve the performances of the protected implementation. We show here that their countermeasure can still be defeated by usual first-order DPA techniques.In another direction, Akkar and Goubin introduced at FSE’2003 a new countermeasure for protecting secret-key cryptographic algorithms against high-order differential power analysis (HO-DPA). As particular case, the “Unique Masking Method” is particularly well suited to the protection of DES implementations. However, we prove in this paper that this method is not sufficient, by exhibiting a (first-order) enhanced differential power analysis attack. We also show how to avoid this new attack.KeywordsTamper-resistant devicesSide-Channel attacksPower AnalysisDPATransformed Masking MethodUnique Masking MethodDESAES

Side-channel attacks, particularly differential power analysis (DPA) attacks, are efficient ways to extract secret keys of the attacked devices by leaked physical information. To resist DPA attacks, hiding and masking methods are commonly used, but it usually resulted in high area overhead and performance degradation. In this brief, a DPA countermeasure circuit based on digital controlled ring oscillators is presented to efficiently resist the first-order DPA attack. The implementation of the critical S-box of the advanced encryption standard (AES) algorithm shows that the area overhead of a single S-box is about 19% without any extra delay in the critical path. Moreover, the countermeasure circuit can be mounted onto different S-box implementations based on composite field or look-up table (LUT). Based on our approach, a DPA-resistant AES chip can be proposed to maintain the same throughput with less than 2K extra gates.

Cryptographic devices with the Advanced Encryption Standard (AES) encryption algorithm are vulnerable to side channel attack, in particular, differential power analysis (DPA). Differential power analysis can be used to reveal the secret key in AES by monitoring the power consumption of the internal circuit and applying statistical processing. In this paper, an evaluation of power analysis attacks of six different AES Sbox designs, namely sum of product (SOP), product of sum (POS), table lookup (TBL), composite field (CF), positive polarity Reed-Miller (PPRM) and 3 stages PPRM, is presented. Comparison of the different AES Sbox implementations in terms of size, performance and SNR analysis is also performed. The results show that the composite field Sbox design is more resistant to attack and smaller than other Sbox designs but operates at a slower speed. This paper also presents a Random Clock mechanism that can be used to increase the resistance of the AES composite field Sbox design to power analysis attack by reducing the overall SNR by 78%.

Since the vulnerability of cryptosystems to differential power analysis (DPA) was reported in 1999, various power analysis attacks and corresponding countermeasures have been studied. With the scaling down of supply voltage and CMOS technology below 90 nm, leakage power plays an increasing role in the overall power dissipation. Future cryptosystems need to address this trend, though it has not been of concern yet in low- cost cryptosystems such as smartcards and RFED tags which currently use older technologies and low performance transistors. In this paper, we explore the impact of leakage power on conventional DPA and the feasibility of a novel leakage-based DPA (LDPA). We first use SPICE simulations to explore the leakage dependence on input patterns of logic gates implemented in 90 nm, 65 nm, and 45 nm CMOS technologies. Then we simulate a successful LDPA on a subset of a DES cryptosystem with only 120 rounds, in contrast to the 200 rounds reported for a conventional DPA in 180 nm technology. Furthermore, we demonstrate how even a DES implementation using a DPA-resistant logic style can be broken with LDPA in 2000 rounds, compared with the conventional DPA using more than 5000 rounds.

The LSI design methodology against Differential Power Analysis (DPA) is important to realize a tamper-resistant cryptographic circuit. In order to verify the DPA resistance before ASIC fabrication, the DPA verification using FPGA is commonly used. However, power traces of ASIC differ from that of FPGA, so the DPA verification on FPGA cannot guarantee the DPA resistance on ASIC. On the other hand, it takes extremely long time to collect the simulated power traces using post-layout netlists of ASIC. Hence, the DPA-resistance verification method using smaller number of power traces is demanded. In this paper, we propose Equivalent Byte Method (EBM) which synchronizes the operation on all Substitution Boxes (S-Boxes) at the attacking round by controlling the plaintexts and the keys. In EBM, the power-consumption profiles of S-Boxes are emphasized by each other, and then the DPA analysis for a correct key is easily distinguished with smaller number of traces. In order to demonstrate the effectiveness of the proposed EBM, AES circuits using DPA-resistant techniques of WDDL and MDPL are implemented on FPGA. As a result, EBM revealed DPA-leak with 1/1000 ~ 1/50 power traces required for the general statistical method.

Encryption and decryption are the two most important complex methods for achieving security in any type of smart devices and systems/machines through transport layer security protocol (TLS). The symmetric key algorithms are the significant method for encrypting and decrypting the data/information using block cipher or stream cipher which is used for TLS protocol. The primary symmetric key block cipher algorithm used in TLS is Advanced Encryption standard (AES) and it provides security based on the key bits used in AES operation. The TLS protocol provides confidentiality(C), integrity (I) and Authenticity (A) in a single pass communication that is Authentication Encryption and Authentication Data (AEAD) between web browser and web server. It uses well known TLS cipher suite AES-GCM (Galois Counter mode) which is commonly used in TLS1.2. Suppose AES-NI hardware acceleration is not available in smart devices like tablets it causes performance issues in smart devices using TLS 1.2 protocol. If the smart device does not possess AES-NI, it can use software for running AES-GCM but it takes a lot of time for encryption/decryption of information, ergo causing the battery performance in smart devices. The newer symmetric Stream cipher CHACHA20-POLY1305 provides AEAD for securing the communication in smart devices thus reducing the battery cycles which is used for TLS 1.3. The paper discusses the pros and cons of AES-GCM authentication encryption used in TLS 1.2.

Differential Power Analysis (DPA) aims at revealing secret keys in cryptographic devices by analyzing their power consumption as side-channel information. Although power consumption models based on transition probability were used to evaluate a DPA-resistance in previous studies, the adequacy of this model has not been confirmed enough. In this paper, we show two experiments about information of power consumption precisely, and show that Random Switching Logic which is one of the DPA-countermeasures is in reality not secure against DPA.

Differential power analysis (DPA) has been shown to be an effective attack on cryptographic systems capable of releaving secret data by measuring power consumption. DPA resistant circuits currently experience severe problems in terms of performance, area, and power. Although different countermeasures to reduce DPA attacks have been proposed and implemented in general, such protections do not make attacks infeasible. Additionally, most are dual rail logic families, Delay Based Dual Rail Precharge Logic (DDPL) with high resistance is presented and significantly lower overheads in performance, area, and power than other DPA resistant logic styles. The Delay Based Dual Rail Precharge Logic (DDPL) shows a certain improvement in Normalized Energy Deviation(NED) with respect to other dual rail logics.

In recent years, there has been widespread adoption of the Internet of Things (IoT) devices, some of which involve the processing of sensitive information. In such devices, cipher-dedicated circuits are often used to encrypt sensitive information. However, the cipher circuits may be still vulnerable to side-channel attacks (SCA), such as differential power analysis (DPA) which exploits information by analyzing power consumption. To cope with DPA, threshold implementation (TI), a masking method which provides provable security, can be adopted in cipher circuits implementation. From the design-productivity perspective, integrating TI into the state-of-the-art high-level synthesis (HLS)-based design flow for cipher circuits implementation is ideal. In this approach, however, mitigating the hardware resource overhead is challenging as have been observed in previous work. In this paper, we propose a novel HLS-based countermeasure that mixes different numbers of shares to reduce the hardware overhead. Our countermeasure demonstrates secure against SCA while simultaneously reducing resource utilization along with a small latency overhead.

Security of cryptographic devices (secure ICs) like smart cards has come under threat from powerful side channel attacks like Differential Power Analysis (DPA). DPA uses power consumption information leaked from the secure IC in conjunction with statistical correlation techniques to retrieve the secret key stored in the secure IC. The most effective countermeasure to resist DPA attacks is to make the power consumption of the secure IC invariant, hence uncorrelated to the input data (secret key). In hardware implementations, this can be achieved by designing the secure IC using Dynamic and Differential Logic (DDL) style. In this paper, we present a novel methodology to design DPA-resistant power invariant secure ICs using Reduced Complementary Dynamic and Differential Logic (RCDDL). The proposed methodology involves strategies to design: 1) RCDDL gates, and 2) secure circuits using RCDDL gates. Experiments show significant improvements in security strength, average power consumption and area, when compared with a similar secure DDL and non-secure static-CMOS logic design styles.

Cryptographic implementation is one of the vital applications for FPGAs with security as its major standpoint. But it still requires a lot of efforts to keep it aloof from attacks like Side Channel Attacks (SCA). One of the major attacks that threaten the security of FPGA implementation of cryptographic algorithm is Differential Power Analysis (DPA). In this paper, we have discussed various approaches to defend against DPAs. These new programs suggested in the different approaches with some results aid in evenly distributing the power consumption in FPGAs making it less prone to DPAs.

Security devices are vulnerable to Differential Power Analysis (DPA) that reveals the key by monitoring the power consumption of the circuits. In this paper, we present the first DPA attack against an FPGA implementation of the Camellia encryption algorithm with all key sizes and evaluate the DPA resistance of the algorithm. The Camellia cryptographic algorithm involves several different key-dependent intermediate operations including S-Box operations. In previous research, it was believed that the Camellia is stronger than AES due to the additional Whitening phase protecting the S-Box operation. However, we propose an attack that bypasses the Whitening phase and targets the S-Box. In this paper, we also discuss a low-cost countermeasure strategy to protect the Pre-whitening / Post-whitening and FL function of Camellia using Dual-rail Precharged Logic and to protect against attacks of the S-Box using Random Delay Insertion.