216 research outputs found
Design Considerations for EM Pulse Fault Injection.
No full textsponsorship: This work was supported in part by the Research Council KU Leuven C1 on Security and Privacy for Cyber-Physical Systems and the Internet of Things with contract number C16/15/058 and through the Horizon 2020 research and innovation programme under Cathedral ERC Advanced Grant 695305. Additionally this work has been partially supported by FWO project VS06717N in collaboration with JSPS. (Research Council KU Leuven C1 on Security and Privacy for Cyber-Physical Systems and the Internet of Things|C16/15/058, Horizon 2020 research and innovation programme under Cathedral ERC Advanced Grant|695305, FWO|VS06717N, JSPS)status: Publishe
Accelerating LTV based homomorphic encryption in reconfigurable hardware
No full textAfter being introduced in 2009, the first fully homomorphic encryption (FHE) scheme has created significant excitement in academia and industry. Despite rapid advances in the last 6 years, FHE schemes are still not ready for deployment due to an efficiency bottleneck. Here we introduce a custom hardware accelerator optimized for a class of reconfigurable logic to bring LTV based somewhat homomorphic encryption (SWHE) schemes one step closer to deployment in real-life applications. The accelerator we present is connected via a fast PCIe interface to a CPU platform to provide homomorphic evaluation services to any application that needs to support blinded computations. Specifically we introduce a number theoretical transform based multiplier architecture capable of efficiently handling very large polynomials. When synthesized for the Xilinx Virtex 7 family the presented architecture can compute the product of large polynomials in under 6.25 msec making it the fastest multiplier design of its kind currently available in the literature and is more than 102 times faster than a software implementation. Using this multiplier we can compute a relinearization operation in 526 msec. When used as an accelerator, for instance, to evaluate the AES block cipher, we estimate a per block homomorphic evaluation performance of 442 msec yielding performance gains of 28.5 and 17 times over similar CPU and GPU implementations, respectively
Robust Profiling for DPA-Style Attacks
No full textAbstract. Profiled side-channel attacks are understood to be powerful when applicable: in the best case when an adversary can comprehensively characterise the leakage, the resulting model leads to attacks requiring a minimal number of leakage traces for success. Such ‘com-plete ’ leakage models are designed to capture the scale, location and shape of the profiling traces, so that any deviation between these and the attack traces potentially produces a mismatch which renders the model unfit for purpose. This severely limits the applicability of profiled attacks in practice and so poses an interesting research challenge: how can we de-sign profiled distinguishers that can tolerate (some) differences between profiling and attack traces? This submission is the first to tackle the problem head on: we propose distinguishers (utilising unsupervised machine learning methods, but also a ‘down-to-earth ’ method combining mean traces and PCA) and evaluate their behaviour across an extensive set of distortions that we apply to representative trace data. Our results show that the profiled distinguishers are effective and robust to distortions to a surprising extent
A Masked Ring-LWE Implementation
No full text© International Association for Cryptologic Research 2015. Lattice-based cryptography has been proposed as a postquantum public-key cryptosystem. In this paper, we present a masked ring-LWE decryption implementation resistant to first-order side-channel attacks. Our solution has the peculiarity that the entire computation is performed in the masked domain. This is achieved thanks to a new, bespoke masked decoder implementation. The output of the ring-LWE decryption are Boolean shares suitable for derivation of a symmetric key. We have implemented a hardware architecture of the masked ring-LWE processor on a Virtex-II FPGA, and have performed side channel analysis to confirm the soundness of our approach. The area of the protected architecture is around 2000 LUTs, a 20% increase with respect to the unprotected architecture. The protected implementation takes 7478 cycles to compute, which is only a factor ×2. 6 larger than the unprotected implementation.sponsorship: The authors would like to thank the CHES 2015 reviewers for their valuable comments. This work has been supported in part by the European Commission through the ICT programme under contracts H2020-ICT-645622 PQCRYPTO, H2020-ICT-644209 HEAT and FP7-ICT-2013-10-SEP-210076296 PRACTICE; by the Research Council KU Leuven TENSE (GOA/11/007); by the Flemish Government FWO G.0550.12N, G.00130.13N and G.0876.14N; and by the Hercules Foundation AKUL/11/19. Oscar Reparaz is funded by a PhD fellowship of the Fund for Scientific Research - Flanders (FWO). Sujoy Sinha Roy was supported by Erasmus Mundus PhD Scholarship. (European Commission through the ICT programme|H2020-ICT-645622 PQCRYPTO, European Commission through the ICT programme|H2020-ICT-644209 HEAT, European Commission through the ICT programme|FP7-ICT-2013-10-SEP-210076296 PRACTICE, Research Council KU Leuven TENSE|GOA/11/007, Flemish Government|FWO G.0550.12N, Flemish Government|G.00130.13N, Flemish Government|G.0876.14N, Hercules Foundation|AKUL/11/19, PhD fellowship of the Fund for Scientific Research - Flanders (FWO), Erasmus Mundus PhD Scholarship, EPSRC|EP/L001802/1)status: Publishe
A New Perspective on Key Switching for BGV-like Schemes
No full textFully homomorphic encryption is a promising approach when computing on encrypted data, especially when sensitive data is involved. For BFV, BGV, and CKKS, three state-of-the-art encryption schemes, the most costly homomorphic primitive is the so-called key switching. While a decent amount of research has been devoted to optimizing other aspects of these schemes, key switching has gone largely untouched. One exception has been a recent work [KLSS23] introducing a new double-decomposition technique. Their contributions are an important addition to the current state-of-the-art with one flaw: They take a limited perspective on key switching parameters and their asymptotic complexity which leads to incorrect conclusions about how effective their approach really is. In our work, we deep dive into key switching and correct, enhance, and improve the current state-of-the-art. We provide a new perspective on key switching parameters for the single- and doubledecomposition techniques, respectively, and show that the former outperforms the latter in most scenarios. Additionally, we revisit an idea by Gentry, Halevi, and Smart [GHS12b] and reduce the number of multiplications
Lightweight Coprocessor for Koblitz Curves: 283-bit ECC Including Scalar Conversion with only 4300 Gates
No full text© International Association for Cryptologic Research 2015. We propose a lightweight coprocessor for 16-bit microcontrollers that implements high security elliptic curve cryptography. It uses a 283-bit Koblitz curve and offers 140-bit security. Koblitz curves offer fast point multiplications if the scalars are given as specific τ-adic expansions, which results in a need for conversions between integers and τ-adic expansions. We propose the first lightweight variant of the conversion algorithm and, by using it, introduce the first lightweight implementation of Koblitz curves that includes the scalar conversion. We also include countermeasures against side-channel attacks making the coprocessor the first lightweight coprocessor for Koblitz curves that includes a set of countermeasures against timing attacks, SPA, DPA and safe-error fault attacks. When the coprocessor is synthesized for 130nm CMOS, it has an area of only 4, 323 GE. When clocked at 16 MHz, it computes one 283-bit point multiplication in 98ms with a power consumption of 97. 70 μW, thus, consuming 9. 56 μJ of energy.sponsorship: S. Sinha Roy was supported by the Erasmus Mundus PhD Scholarship and K. Jarvinen was funded by FWO Pegasus Marie Curie Fellowship. This work was supported by the Research Council KU Leuven: TENSE (GOA/11/007), by iMinds, by the Flemish Government, FWO G.0550.12N, G.00130.13N and FWO G.0876.14N, and by the Hercules Foundation AKUL/11/19. We thank Bohan Yang for his help with ASIC synthesis and simulations. (Erasmus Mundus PhD Scholarship, FWO Pegasus Marie Curie Fellowship, Research Council KU Leuven: TENSE|GOA/11/007, iMinds, Flemish Government|FWO G.0550.12N, Flemish Government|G.00130.13N, Flemish Government|FWO G.0876.14N, Hercules Foundation|AKUL/11/19, EPSRC|EP/L001802/1)status: Publishe
Implementing and Optimizing Matrix Triples with Homomorphic Encryption
No full textIn today’s interconnected world, data has become a valuable asset, leading to a growing interest in protecting it through techniques such as privacy-preserving computation. Two well-known approaches are multi-party computation and homomorphic encryption with use cases such as privacy-preserving machine learning evaluating or training neural networks. For multi-party computation, one of the fundamental arithmetic operations is the secure multiplication in the malicious security model and by extension the multiplication of matrices which is expensive to compute in the malicious model. Transferring the problem of secure matrix multiplication to the homomorphic domain enables savings in communication complexity, reducing the main bottleneck.
In this work, we implement and optimize the homomorphic generation of matrix triples. We provide an open-source implementation for the leveled BGV (Brakerski Gentry Vaikuntanathan) scheme supporting plaintext moduli of arbitrary size using state-of-the-art implementation techniques. We also provide a new, use-case specific approach to parameter generation for leveled BGV-like schemes heuristically optimizing for computation time and taking into account architecture-specific constraints. Finally, we provide an in-depth analysis of the homomorphic circuit enabling the re-use of key switching keys and eliminating constant multiplications, combining our results in an implementation to generate homomorphic matrix triples for arbitrary plaintext moduli.
Our implementation is publicly available and up to faster compared to previous work while also providing new time-memory trade-offs for different computing environments. Furthermore, we implement and evaluate additional, use-case specific optimization opportunities such as matrix slicing for the matrix triple generation
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