Cryptographic circuits are nowadays subject to attacks that no longer focus on the algorithm but rather on its physical implementation. Attacks exploiting information leaked by the hardware implementation are called side-channel attacks (SCAs). Among these attacks, the differential power analysis (DPA) established by Paul Kocher et al. in 1998 represents a serious threat for CMOS VLSI implementations. Different countermeasures that aim at reducing the information leaked by the power consumption have been published. Some of these countermeasures use sophisticated back-end-level constraints to increase their strength. As suggested by some preliminary works (e.g., by Li from Cambridge University), the prediction of the actual security level of such countermeasures remains an open research area. This paper tackles this issue on the example of the AES SubBytes primitive. Thirteen implementations of SubBytes, in unprotected, WDDL, and SecLib logic styles with various back-end-level arrangements are studied. Based on simulation and experimental results, we observe that static evaluations on extracted netlists are not relevant to classify variants of a countermeasure. Instead, we conclude that the fine-grained timing behavior is the main reason for security weaknesses. In this respect, we prove that SecLib, immune to early-evaluation problems, is much more resistant against DPA than WDDL.

This paper presents a RTR FPGA embedded in a System on Chip fabricated in 130nm CMOS process. Various aspects of the design flow, from automation to floor-planning are discussed. We explain the measures taken in the FPGA design to guarantee RTR functionality free of electrical conflicts, and we present a flow based on Altera synthesis tools to implement IPs(Hardware Blocks) in this FPGA. We demonstrate the full functionality with experiments on the FPGA, and as conclusion we highlight the limitations and future research directions.

This article does a purely mathematical analysis based on generic models, and the idea is to investigate the possibility of using tiling patterns other than Manhattan grid in FPGAs. The goal of our research is to evolve FPGA architectures with advances in technology, and specifically better utilization of available interconnect layers. We propose a method to evaluate tiling patterns based on the first principles ( i.e Rent's Rule, Donath's result, equivalence of wire flux and wire length). We show that, use of tiling patterns formed with higher order polygons can improve the speed and area performances of an FPGA. This gain is highly dependent on depopulation schemes and other parameters. However for generic tiling patterns with crossbar switchboxes there is a 22% gain in area for the hexagonal tiling pattern, and a 30% gain in area for the octagonal tiling pattern. Moreover the average interconnect length is around 15% lesser for hexagonal and 31% lesser for the octagonal tiling compared to square tiling. We can expect a proportional increase in speed. We also present a comparative plot of total interconnect lengths for these tiling patterns and the hierarchical gate arrays

Field programmable gate arrays (FPGAs) become very popular for embedded cryptographic operations. In order to resist side-channel attacks, FPGAs must implement reasoned countermeasures. The most efficient way to mitigate attacks is to adopt a gate-level protection. Two secure gates families exist: those that ldquohiderdquo and those that ldquomaskrdquo side-channel leakage. In this article, we detail methods to reduce the size of wave dynamic differential logic (WDDL) implementations. These circuits are designed to hide any physical leak by ensuring a data-independent activity. This study is meant to be generic, and thus applies to any 4 rarr 1 LUT-based FPGAs. Further optimizations can be reached by taking advantage of some FPGAs proprietary features. Our solutions include RTL code modification, synthesizer usage (potentially in a re-entrant way), and ad hoc mapping. We show that linear parts of algorithms can be delegated to a synthesizer, but that non-linear parts are better off to be handled with heuristics. We present a 23 % area gain over the state-of-the-art as for the positive WDDL triple-DES symmetric encryption algorithm.

Logic styles with constant power consumption are promising solutions to counteract side-channel attacks on sensitive cryptographic devices. Recently, one vulnerability has been identified in a standard-cell-based power-constant logic called WDDL. Another logic, nicknamed SecLib, is considered and does not present the flaw of WDDL. In this paper, we evaluate the security level of WDDL and SecLib. The methodology consists in embedding in a dedicated circuit one unprotected DES coprocessor along with two others, implemented in WDDL and in SecLib. One essential part of this paper is to describe the conception of the cryptographic ASIC, devised to foster side-channel cryptanalyses, in a view to model the strongest possible attacker. The same analyses are carried out successively on the three DES modules. We conclude that, provided that the back-end of the WDDL module is carefully designed, its vulnerability cannot be exploited by the state-of-the-art attacks. Similarly, the SecLib DES module resists all assaults. However, using a principal component analysis, we show that WDDL is more vulnerable than SecLib. The statistical dispersion of WDDL, which reflects the correlation between the secrets and the power dissipation, is proved to be an order of magnitude higher than that of SecLib.

With the growing security needs of applications such as homeland security or banking, the frequent updates in cryptographic standards and the high ASIC costs, the ciphering algorithms on an asynchronous embedded FPGA co-processor are becoming a viable alternative. Within the SAFE project, a novel architecture of asynchronous e-FPGA has been proposed. This architecture is natively robust against side channel attacks such as simple and differential power analysis or clock based fault attacks. Simulation-based security proofs are also presented.

Unsecured electronic circuits leak physical syndromes correlated to the data they handle. Side-channels attacks, like SPA or DPA, exploit this information leakage. We provide balanced and memoryless CMOS structures for a 2-input secured NAND gate.