In this paper, we define and explore proofs of retrievability (PORs). A POR scheme enables an archive or back-up service (prover) to produce a concise proof that a user (verifier) can retrieve a target file F, that is, that the archive retains and reliably transmits file data sufficient for the user to recover F in its entirety.A POR may be viewed as a kind of cryptographic proof of knowledge (POK), but one specially designed to handle a large file (or bitstring) F. We explore POR protocols here in which the communication costs, number of memory accesses for the prover, and storage requirements of the user (verifier) are small parameters essentially independent of the length of F. In addition to proposing new, practical POR constructions, we explore implementation considerations and optimizations that bear on previously explored, related schemes.In a POR, unlike a POK, neither the prover nor the verifier need actually have knowledge of F. PORs give rise to a new and unusual security definition whose formulation is another contribution of our work.We view PORs as an important tool for semi-trusted online archives. Existing cryptographic techniques help users ensure the privacy and integrity of files they retrieve. It is also natural, however, for users to want to verify that archives do not delete or modify files prior to retrieval. The goal of a POR is to accomplish these checks without users having to download the files themselves. A POR can also provide quality-of-service guarantees, i.e., show that a file is retrievable within a certain time bound.

PORs: Proofs of Retrievability for Large Files

Modern cloud architectures rely on each server running its own networking stack to implement policies such as tunneling for virtual networks, security, and load balancing. However, these networking stacks are becoming increasingly complex as features are added and as network speeds increase. Running these stacks on CPU cores takes away processing power from VMs, increasing the cost of running cloud services, and adding latency and variability to network performance.

We present Azure Accelerated Networking (AccelNet), our solution for offloading host networking to hardware, using custom Azure SmartNICs based on FPGAs. We define the goals of AccelNet, including programmability comparable to software, and performance and efficiency comparable to hardware. We show that FPGAs are the best current platform for offloading our networking stack as ASICs do not provide sufficient programmability, and embedded CPU cores do not provide scalable performance, especially on single network flows.

Azure SmartNICs implementing AccelNet have been deployed on all new Azure servers since late 2015 in a fleet of >1M hosts. The AccelNet service has been available for Azure customers since 2016, providing consistent <15µs VM-VM TCP latencies and 32Gbps throughput, which we believe represents the fastest network available to customers in the public cloud. We present the design of AccelNet, including our hardware/software codesign model, performance results on key workloads, and experiences and lessons learned from developing and deploying AccelNet on FPGA-based Azure SmartNICs.

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Azure accelerated networking: SmartNICs in the public cloud

The existing ways to encrypt images based on compressive sensing usually treat the whole measurement matrix as the key, which renders the key too large to distribute and memorize or store. To solve this problem, a new image compression–encryption hybrid algorithm is proposed to realize compression and encryption simultaneously, where the key is easily distributed, stored or memorized. The input image is divided into 4 blocks to compress and encrypt, then the pixels of the two adjacent blocks are exchanged randomly by random matrices. The measurement matrices in compressive sensing are constructed by utilizing the circulant matrices and controlling the original row vectors of the circulant matrices with logistic map. And the random matrices used in random pixel exchanging are bound with the measurement matrices. Simulation results verify the effectiveness, security of the proposed algorithm and the acceptable compression performance.

Novel image compression–encryption hybrid algorithm based on key-controlled measurement matrix in compressive sensing

Book review: Applied cryptography: Protocols, algorithms, and source code in C

Internet of Things (IoT) is transforming everyone’s life by providing features, such as controlling and monitoring of the connected smart objects. IoT applications range over a broad spectrum of services including smart cities, homes, cars, manufacturing, e-healthcare, smart control system, transportation, wearables, farming, and much more. The adoption of these devices is growing exponentially, that has resulted in generation of a substantial amount of data for processing and analyzing. Thus, besides bringing ease to the human lives, these devices are susceptible to different threats and security challenges, which do not only worry the users for adopting it in sensitive environments, such as e-health, smart home, etc., but also pose hazards for the advancement of IoT in coming days. This article thoroughly reviews the threats, security requirements, challenges, and the attack vectors pertinent to IoT networks. Based on the gap analysis, a novel paradigm that combines a network-based deployment of IoT architecture through software-defined networking (SDN) is proposed. This article presents an overview of the SDN along with a thorough discussion on SDN-based IoT deployment models, i.e., centralized and decentralized. We further elaborated SDN-based IoT security solutions to present a comprehensive overview of the software-defined security (SDSec) technology. Furthermore, based on the literature, core issues are highlighted that are the main hurdles in unifying all IoT stakeholders on one platform and few findings that emphases on a network-based security solution for IoT paradigm. Finally, some future research directions of SDN-based IoT security technologies are discussed.

An In-Depth Analysis of IoT Security Requirements, Challenges, and Their Countermeasures via Software-Defined Security

Anonymous hybrid mutual authentication and key agreement scheme for wireless body area network

Block compressive sensing

Design, implementation and analysis of hardware efficient stream ciphers using LFSR based hash functions

This brief presents a compressive sensing (CS)-based lightweight cryptosystem for Internet of Things (IoT) applications. In a recent study, Pudi et al. presented two efficient CS-based cryptosystems: CS using stream cipher (CSSC) and CSSC with encryption of MSB-bits (CSSC-EM). The proposed work aims to improve the energy efficiency of CSSC-EM further, without compromising security. While the random Bernoulli sensing matrix in CSSC-EM offers greater flexibility for embedding security, it suffers from a high computational cost. In contrast, the deterministic nature of the structurally random matrix (SRM) rectifies the computational burden, making the CS encoder energy-conserving. In this brief, we first quantify the security of CSSC and CSSC-EM against a chosen plaintext attack (CPA). Based on this cryptanalysis, we propose a CS-based energy efficient encryption scheme using an SRM for multimedia IoT. The artificial noise is injected to quantized CS measurements to resist CPA, based on the rate-distortion analysis of CS using SRM. Further, bitstream resulting from entropy coding of quantized CS measurements is randomly corrupted through an intentional error vector to achieve uniform probability distribution. We develop an efficient hardware implementation of the overall cryptosystem based on a linear feedback shift register. Analytical and simulation results are presented to validate resistance of the proposed system against various attacks.

Design and Analysis of Compressive Sensing-Based Lightweight Encryption Scheme for Multimedia IoT

Proposal for a secure stream cipher based on Linear Feedback Shift Registers (LFSR) is presented here. In this method, shift register structure used for polynomial modular division is combined with LFSR keystream generator to yield a new keystream generator with much higher periodicity. Security is brought into this structure by using the Boolean function to combine state bits of the LFSR keystream generator and taking the output through the Boolean function. This introduces non-linearity and security into the structure in a way similar to the Non-linear filter generator. The security and throughput of the suggested stream cipher is found to be much greater than the known LFSR based structures for the same key length. Keywords—Linear Feedback Shift Register, Stream Cipher, Filter generator, Keystream generator, Modular division circuit

P. P. Deepthi

Papers

Anonymous hybrid mutual authentication and key agreement scheme for wireless body area network

Block compressive sensing

Design, implementation and analysis of hardware efficient stream ciphers using LFSR based hash functions

Design and Analysis of Compressive Sensing-Based Lightweight Encryption Scheme for Multimedia IoT

Hardware Stream Cipher Based On LFSR and Modular Division Circuit