As concerns are increasingly raised about data privacy, encrypted database management system (DBMS) based on fully homomorphic encryption (FHE) attracts increasing research attention, as FHE permits DBMS to be directly outsourced to cloud servers without revealing any plaintext data. However, the real-world deployment of FHE-based DBMS faces two main challenges: i) high computational latency, and ii) lack of elastic query processing capability, both of which stem from the inherent limitations of the underlying FHE operators. Here, we introduce HE3DB, a fully homomorphically encrypted, efficient and elastic DBMS framework based on a new FHE infrastructure. By proposing and integrating new arithmetic and logic homomorphic operators, we devise fast and high-precision homomorphic comparison and aggregation algorithms that enable a variety of SQL queries to be applied over FHE ciphertexts, e.g., compound filter-aggregation, sorting, grouping, and joining. In addition, in contrast to existing encrypted DBMS that only support aggregated information retrieval, our framework permits further server-side elastic analytical processing over the queried FHE ciphertexts, such as private decision tree evaluation. In the experiment, we rigorously study the efficiency and flexibility of HE3DB. We show that, compared to the state-of-the-art techniques, HE3DB can homomorphically evaluate end-to-end SQL queries as much as 41X-299X faster than the state-of-the-art solution, completing a TPC-H query over a 16-bit 10K-row database within 241 seconds.

Ising model based solver have gained increasing attention due to their efficiency in finding approximate solutions for combinatorial optimization problems. However, when solving doubly constrained problems, such as traveling salesman problem using the Ising model-based solver, both the execution speed and the quality of solutions deteriorate significantly due to the quadratically increasing spin counts and strong constraints placed on the spins. In this paper, we propose a recursive clustering approach that accelerates the calculations of the Ising model and that also helps to obtain high-quality solutions. Through evaluations using the TSP benchmarks, the qualities with the proposed method have been improved by up to 67.1% and runtime were reduced by 73.8x.

This work presents a multilevel approximation exploration undertaken on the Ring-Learning-with-Errors (R-LWE)-based public-key cryptographic (PKC) schemes that belong to quantum-resilient cryptography algorithms. Among the various quantum-resilient cryptography schemes proposed in the currently running NIST’s post-quantum cryptography (PQC) standardization plan, the lattice-based learning-with-error (LWE) schemes have emerged as the most viable and preferred class for the Internet of Things (IoT) applications due to their compact area and memory footprint compared to other alternatives. However, compared to the classical schemes used today, R-LWE is much harder a challenge to fit on embedded IoT (end-node) devices, due to their stricter resource constraints (lower area, memory, and energy budgets) as well as their limited computational capabilities. To the best of our knowledge, this is the first endeavor exploring the inherent approximate nature of the LWE problem to undertake a multilevel approximate R-LWE (AxRLWE) architecture with respective security estimates opt for lightweight IoT devices. Undertaking AxRLWE on field-programmable gate arrays (FPGAs), we benchmarked a 64% area reduction cost compared to earlier accurate R-LWE designs at the cost of reduced quantum security. For the application-specific integrated circuits (ASICs) with 45-nm CMOS technology, AxRLWE was benchmarked to fit well within the same area budget of a lightweight ECC processor and consume a third of energy compared to special class of R-Binary LWE (R-BLWE) designs being proposed for an IoT, with a better security level.

Fully homomorphic encryption (FHE) based database outsourcing is drawing growing research interests. At its current state, there exist two primary obstacles against FHE-based encrypted databases (EDBs): i) low data precision, and ii) high computational latency. To tackle the precision-performance dilemma, we introduce ArcEDB, a novel FHE-based SQL evaluation infrastructure that simultaneously achieves high data precision and fast query evaluation. Based on a set of new plaintext encoding schemes, we are able to execute arbitrary-precision ciphertext-to-ciphertext homomorphic comparison orders of magnitude faster than existing methods. Meanwhile, we propose efficient conversion algorithms between the encoding schemes to support highly composite SQL statements, including advanced filter-aggregation and multi-column synchronized sorting. We perform comprehensive experiments to study the performance characteristics of ArcEDB. In particular, we show that ArcEDB can be up to 57× faster in homomorphic filtering and up to 20× faster over end-to-end SQL queries when compared to the state-of-the-art FHE-based EDB solutions. Using ArcEDB, a SQL query over a 10K-row time-series EDB with 64-bit timestamps only runs for under one minute.

Recently, the application of multi-party secure computing schemes based on homomorphic encryption in the field of machine learning attracts attentions across the research fields. Previous studies have demonstrated that secure protocols adopting packed additive homomorphic encryption (PAHE) schemes based on the ring learning with errors (RLWE) problem exhibit significant practical merits, and are particularly promising in enabling efficient secure inference in machine-learning-as-a-service applications. In this work, we introduce a new technique for performing homomorphic linear transformation (HLT) over PAHE ciphertexts. Using the proposed HLT technique, homomorphic convolutions and inner products can be executed without the use of number theoretic transform and the rotate-and-add algorithms that were proposed in existing works. To maximize the efficiency of the HLT technique, we propose APAS, a hardware-software co-design framework consisting of approximate arithmetic units for the hardware acceleration of HLT. In the experiments, we use actual neural network architectures as benchmarks to show that APAS can improve the computational and communicational efficiency of homomorphic convolution by $8\times $ and $3\times $ , respectively, with an energy reduction of up to $26\times $ as compared to the ASIC implementations of existing methods.

Acceleration of deep neural network (DNN) inference has gained increasing attention recently with the wide adoption of DNNs for practical applications. For computer vision tasks where inputs are images, existing works mostly focus on improving the throughput of inference for multiple images. However, in many real-time applications, it is critical to reduce the latency of a single image inference, which is more complicated than improving the throughput because of the inherent data dependencies. On the other hand, from human brain's perspective, the complexity in our visual surroundings is first encoded as a pattern of light on a two dimensional array of photoreceptors, with little direct resemblance to the original input or the ultimate percept. Within just a few hundred microns of retinal thickness, this initial signal encoded by our photoreceptors must be transformed into an adequate representation of the entire visual scene. Inspired by how the retina helps human brain incept new information efficiently, we present an end-to-end structured framework built using any existing convolutional neural network (CNN) as the backbone. The proposed framework, called VisualNet, can create task parallelism for the backbone during the inference of a single image. Experiments using a number of neural networks for the ImageNet classification task and the CIFAR-10 classification task on GPUs and CPUs show that the proposed VisualNet reduces the latency of the regular network it builds on by up to 80.6% when both are fully parallelized with state-of-the-art acceleration libraries. At the same time, VisualNet can achieve similar or slightly higher accuracy.