State-of-the-art asynchronous Byzantine Fault Tolerance (BFT) protocols integrate a partially-synchronous optimistic path. The holy grail in this paradigm is to match the performance of a partially-synchronous protocol in favorable situations and match the performance of a purely asynchronous protocol in unfavorable situations. Several prior works have made progress toward this goal by matching the efficiency of a partially-synchronous protocol in favorable conditions. However, their...

Existing oblivious systems offer robust security by concealing memory access patterns, but they encounter significant scalability and performance challenges. Recent efforts to enhance the practicality of these systems involve embedding oblivious computation, e.g., oblivious sorting and shuffling, within Trusted Execution Environments (TEEs). For instance, oblivious sort has been heavily utilized: in Oblix (S&P'18), when oblivious indexes are created and accessed; in Snoopy's high-throughput...

In this work, we present novel protocols over rings for semi-honest secure three-party computation (3PC) and malicious four-party computation (4PC) with one corruption. While most existing works focus on improving total communication complexity, challenges such as network heterogeneity and computational complexity, which impact MPC performance in practice, remain underexplored. Our protocols address these issues by tolerating multiple arbitrarily weak network links between parties...

We introduce YPIR, a single-server private information retrieval (PIR) protocol that achieves high throughput (up to 83% of the memory bandwidth of the machine) without any offline communication. For retrieving a 1-bit (or 1-byte) record from a 32 GB database, YPIR achieves 12.1 GB/s/core server throughput and requires 2.5 MB of total communication. On the same setup, the state-of-the-art SimplePIR protocol achieves a 12.5 GB/s/core server throughput, requires 1.5 MB total communication, but...

Fully Homomorphic Encryption (FHE) enables computation on encrypted data, holding immense potential for enhancing data privacy and security in various applications. Presently, FHE adoption is hindered by slow computation times, caused by data being encrypted into large polynomials. Optimized FHE libraries and hardware acceleration are emerging to tackle this performance bottleneck. Often, these libraries implement the Number Theoretic Transform (NTT) algorithm for efficient polynomial...

Homomorphic encryption is a powerful privacy-preserving technology that is notoriously difficult to configure and use, even for experts. The key difficulties include restrictive programming models of homomorphic schemes and choosing suitable parameters for an application. In this tutorial, we outline methodologies to solve these issues and allow for conversion of any application to the encrypted domain using both leveled and fully homomorphic encryption. The first approach, called...

The conversion between arithmetic and Boolean mask representations (A2B & B2A) is a crucial component for side-channel resistant implementations of lattice-based cryptography. In this paper, we present a first- and high-order masked, unified hardware implementation which can perform both A2B & B2A conversions. We optimize the operation on several layers of abstraction, applicable to any protection order. First, we propose novel higher-order algorithms for the secure addition and B2A...

Central Bank Digital Currencies refer to the digitization of lifecycle's of central bank money in a way that meets first of a kind requirements for transparency in transaction processing, interoperability with legacy or new world, and resilience that goes beyond the traditional crash fault tolerant model. This comes in addition to legacy system requirements for privacy and regulation compliance, that may differ from central bank to central bank. This paper introduces a novel framework for...

The threat posed by quantum computing has precipitated an urgent need for post-quantum cryptography. Recently, the post-quantum digital signature draft FIPS 204 has been published, delineating the details of the ML-DSA, which is derived from the CRYSTALS-Dilithium. Despite these advancements, server environments, especially those equipped with GPU devices necessitating high-throughput signing, remain entrenched in classical schemes. A conspicuous void exists in the realm of GPU...

State-machine replication (SMR) allows a state machine to be replicated across a set of replicas and handle clients' requests as a single machine. Most existing SMR protocols are leader-based, i.e., requiring a leader to order requests and coordinate the protocol. This design places a disproportionately high load on the leader, inevitably impairing the scalability. If the leader fails, a complex and bug-prone fail-over protocol is needed to switch to a new leader. An adversary can also...

Tiptoe is a private web search engine that allows clients to search over hundreds of millions of documents, while revealing no information about their search query to the search engine’s servers. Tiptoe’s privacy guarantee is based on cryptography alone; it does not require hardware enclaves or non-colluding servers. Tiptoe uses semantic embeddings to reduce the problem of private full-text search to private nearest-neighbor search. Then, Tiptoe implements private nearest-neighbor search...

Most of the current fully homomorphic encryption (FHE) schemes are based on either the learning-with-errors (LWE) problem or on its ring variant (RLWE) for storing plaintexts. During the homomorphic computation of FHE schemes, RLWE formats provide high throughput when considering several messages, and LWE formats provide a low latency when there are only a few messages. Efficient conversion can bridge the advantages of each format. However, converting LWE formats into RLWE format, which is...

We present a non-interactive and public verifier scheme that allows one to assert the asset of a financial organization instantly and incrementally in zero knowledge with high throughput. It is enabled by the recent breakthrough in lookup argument, where the prover cost can be independent of the lookup table size after a pre-processing step. We extend the cq protocol and develop an aggregated non-membership proof for zero knowledge sets. Based on it, we design a non-intrusive protocol that...

Proof-of-work (PoW) blockchain protocols based on directed acyclic graphs (DAGs) have demonstrated superior transaction confirmation performance compared to their chain-based predecessors. However, it is uncertain whether their security deteriorates in high-throughput settings similar to their predecessors, because their acceptance of simultaneous blocks and complex block dependencies presents challenges for rigorous security analysis. We address these challenges by analyzing DAG-based...

Four recent trends have emerged in the evolution of authenticated encryption schemes: (1) Regarding simplicity, the adoption of public permutations as primitives allows for sparing a key schedule and the need for storing round keys; (2) using the sums of permutation outputs, inputs, or outputs has been a well-studied means to achieve higher security beyond the birthday bound; (3) concerning robustness, schemes should provide graceful security degradation if a limited amount of nonces...

Secure Machine Learning as a Service is a viable solution where clients seek secure delegation of the ML computation while protecting their sensitive data. We propose an efficient method to securely evaluate deep standard convolutional neural networks based on CKKS fully homomorphic encryption, in the manner of batch inference. In this paper, we introduce a packing method called Channel-by-Channel Packing that maximizes the slot compactness and single-instruction-multipledata capabilities in...

We revisit batch signatures (previously considered in a draft RFC, and used in multiple recent works), where a single, potentially expensive, "inner" digital signature authenticates a Merkle tree constructed from many messages. We formalise a construction and prove its unforgeability and privacy properties. We also show that batch signing allows us to scale slow signing algorithms, such as those recently selected for standardisation as part of NIST's post-quantum project, to high...

We describe high-throughput threshold protocols with guaranteed output delivery for generating Schnorr-type signatures. The protocols run a single message-independent interactive ephemeral randomness generation procedure (e.g., DKG) followed by a \emph{non-interactive} multi-message signature generation procedure. The protocols offer significant increase in throughput already for as few as ten parties while remaining highly-efficient for many hundreds of parties with thousands of signatures...

The US National Institute of Standards and Technology initiated a standardization process for post-quantum cryptography in 2017, with the aim of selecting key encapsulation mechanisms and signature schemes that can withstand the threat from emerging quantum computers. In 2022, Falcon was selected as one of the standard signature schemes, eventually attracting effort to optimize the implementation of Falcon on various hardware architectures for practical applications. Recently, Mitaka was...

Flow is a high-throughput blockchain with a dedicated step for executing the transactions in a block and a subsequent verification step performed by Verification Nodes. To enforce integrity of the blockchain, the protocol requires a component that prevents Verification Nodes from approving execution results without checking. In our preceding work, we have sketched out an approach called Specialized Proof of Confidential Knowledge (SPoCK). Using SPoCK, nodes can provide evidence to a third...

TRNG is an essential component for security applications. A vulnerable TRNG could be exploited to facilitate potential attacks or be related to a reduced key space, and eventually results in a compromised cryptographic system. A digital FIRO-/GARO-based TRNG with high throughput and high entropy rate was introduced by Jovan Dj. Golić (TC’06). However, the fact that periodic oscillation is a main failure of FIRO-/GARO-based TRNGs is noticed in the paper (Markus Dichtl, ePrint’15). We verify...

Fully Homomorphic Encryption (FHE) is a technique that allows computation on encrypted data. It has the potential to drastically change privacy considerations in the cloud, but high computational and memory overheads are preventing its broad adoption. TFHE is a promising Torus-based FHE scheme that heavily relies on bootstrapping, the noise-removal tool invoked after each encrypted logical/arithmetical operation. We present FPT, a Fixed-Point FPGA accelerator for TFHE bootstrapping. FPT...

This paper analyses the lightweight, sponge-based NAEAD mode $\textsf{ISAP}$, one of the finalists of the NIST Lightweight Cryptography (LWC) standardisation project, that achieves high-throughput with inherent protection against differential power analysis (DPA). We observe that $\textsf{ISAP}$ requires $256$-bit capacity in the authentication module to satisfy the NIST LWC security criteria. In this paper, we study the analysis carefully and observe that this is primarily due to the...

Classic McEliece is a code-based quantum-resistant public-key scheme characterized with relative high encapsulation/decapsulation speed and small cipher- texts, with an in-depth analysis on its security. However, slow key generation with large public key size make it hard for wider applications. Based on this observation, a high-throughput key generator in hardware, is proposed to accelerate the key generation in Classic McEliece based on algorithm-hardware co-design. Meanwhile the storage...

Physically Unclonable Functions~(PUFs) have been a potent choice for enabling low-cost, secure communication. However, the state-of-the-art strong PUFs generate single-bit response. So, we propose PUF-COTE: a high throughput architecture based on linear feedback shift register and a strong PUF as the ``base''-PUF. At the same time, we obfuscate the challenges to the ``base''-PUF of the final construction. We experimentally evaluate the quality of the construction by implementing it on Artix...

We present UnTraceable Transactions (UTT), a system for decentralized ecash with accountable privacy. UTT is the first ecash system that obtains three critical properties: (1) it provides decentralized trust by implementing the ledger, bank, auditor, and registration authorities via threshold cryptography and Byzantine Fault Tolerant infrastructure; (2) it balances accountability and privacy by implementing anonymity budgets: users can anonymously send payments, but only up to a limited...

We revisit decentralized random beacons with a focus on practical distributed applications. Decentralized random beacons (Beaver and So, Eurocrypt 1993) provide the functionality for $n$ parties to generate an unpredictable sequence of bits in a way that cannot be biased, which is useful for any decentralized protocol requiring trusted randomness. Existing beacon constructions are highly inefficient in practical settings where protocol parties need to rejoin after crashes or disconnections,...

The emergence of cloud-computing has raised important privacy questions about the data that users share with remote servers. While data in transit is protected using standard techniques like Transport Layer Security (TLS), most cloud providers have unrestricted plaintext access to user data at the endpoint. Fully Homomorphic Encryption (FHE) offers one solution to this problem by allowing for arbitrarily complex computations on encrypted data without ever needing to decrypt it....

Dot-product is a widely used operation in many machine learning and scientific computing algorithms. Recently, NVIDIA has introduced dot-product instructions (DP2A and DP4A) in modern GPU architectures, with the aim of accelerating machine learning and scientific computing applications. These dot-product instructions allow the computation of multiply-and-add instructions in a clock cycle, effectively achieving higher throughput compared to conventional 32-bit integer units. In this paper,...

Existing oblivious storage systems provide strong security by hiding access patterns, but do not scale to sustain high throughput as they rely on a central point of coordination. To overcome this scalability bottleneck, we present Snoopy, an object store that is both oblivious and scalable such that adding more machines increases system throughput. Snoopy contributes techniques tailored to the high-throughput regime to securely distribute and efficiently parallelize every system component...

ChaCha is a high-throughput stream cipher designed with the aim of ensuring high-security margins while achieving high performance on software platforms. RISC-V, an emerging, free, and open Instruction Set Architecture (ISA) is being developed with many instruction set extensions (ISE). ISEs are a native concept in RISC-V to support a relatively small RISC-V ISA to suit different use-cases including cryptographic acceleration via either standard or custom ISEs. This paper proposes a...

Secure communication is an important aspect Internet of Things (IoT) applications in order to avoid cyber-security attacks and privacy issue. One of the key security aspects is data integrity, which can be protected by employing cryptographic hash functions. Recently, US National Institute of Standards and Technology (NIST) had initialized a competition to standardize lightweight hash functions targeting constrained devices, which can be used in IoT applications. The communication in IoT...

CRYSTALS-Dilithium as a lattice-based digital signature scheme has been selected as a finalist in the PQC standardization process of NIST. As part of this selection, a variety of software implementations have been evaluated regarding their performance and memory requirements for platforms like x86 or ARM Cortex-M4. In this work, we present a first set of FPGA implementations for the low-end Xilinx Artix-7 platform, evaluating the peculiarities of the scheme in hardware, reflecting all...

Galois and Fibonacci are two different configurations of stream ciphers. Because the Fibonacci configuration is more convenient for cryptanalysis, most ciphers are designed as Fibonacci-configured. So far, although many transformations between Fibonacci and Galois configurations have been proposed, there is no sufficient analysis of their respective hardware performance. The 128-bit secret key stream cipher Espresso, its Fibonacciconfigured variant and linear Fibonacci variant have a similar...

FrodoKEM is a lattice-based key encapsulation mechanism, currently a semi-finalist in NIST’s post-quantum standardization effort. A condition for these candidates is to use NIST standards for sources of randomness (i.e., seed-expanding), and as such most candidates utilize SHAKE, an XOF defined in the SHA-3 standard. However, for many of the candidates, this module is a significant implementation bottleneck. Trivium is a lightweight, ISO standard stream cipher which performs well in hardware...

Being based on a sound theoretical basis, masking schemes are commonly applied to protect cryptographic implementations against Side-Channel Analysis (SCA) attacks. Constructing SCA-protected AES, as the most widely deployed block cipher, has been naturally the focus of several research projects, with a direct application in industry. The majority of SCA-secure AES implementations introduced to the community opted for low area and latency overheads considering Application-Specific Integrated...

Although large numbers of hardware and software implementations have been proposed to accelerate lattice-based cryptography, Saber, a module-LWR-based algorithm, which has advanced to second round of the NIST standardization process, has not been adequately supported by the current solutions. Based on these motivations, a high-performance crypto-processor is proposed based on an algorithm-hardware co-design in this paper. First, a hierarchical Karatsuba calculating framework, a...

Quantum computers promise to solve hard mathematical problems such as integer factorization and discrete logarithms in polynomial time, making standardized public-key cryptography (such as digital signature and key agreement) insecure. Lattice-Based Cryptography (LBC) is a promising post-quantum public-key cryptographic protocol that could replace standardized public-key cryptography, thanks to the inherent post-quantum resistant properties, efficiency, and versatility. A key mathematical...

With the dawn of quantum computers, higher security than $128$ bits has become desirable for primitives and modes. During the past decade, highly secure hash functions, MACs, and encryption schemes have been built primarily on top of keyless permutations, which simplified their analyses and implementation due to the absence of a key schedule. However, the security of these modes is most often limited to the birthday bound of the state size, and their analysis may require a different security...

Saber is a module lattice-based CCA-secure key encapsulation mechanism (KEM) which has been shortlisted for the second round of NIST's Post Quantum Cryptography Standardization project. To attain simplicity and efficiency on constrained devices, the Saber algorithm is serial by construction. However, on high-end platforms, such as modern Intel processors with AVX2 instructions, Saber achieves limited speedup using vector processing instructions due to its serial nature. In this paper we...

Quantum computers threaten to compromise public-key cryptography schemes such as DSA and ECDSA in polynomial time, which poses an imminent threat to secure signal processing. The cryptography community has responded with the development and standardization of post-quantum cryptography (PQC) algorithms, a class of public-key algorithms based on hard problems that no known quantum algorithms can solve in polynomial time. Ring learning with error (RLWE) lattice- based cryptographic (LBC)...

As one of the post-quantum protocol candidates, the supersingular isogeny key encapsulation (SIKE) protocol delivers promising public and secret key sizes over other candidates. Nevertheless, the considerable computations form the bottleneck and limit its practical applications. The modular multiplication operations occupy a large proportion of the overall computations required by the SIKE protocol. The VLSI implementation of the high-speed modular multiplier remains a big challenge. In this...

In previous work, Boemer et al. introduced nGraph-HE, an extension to the Intel nGraph deep learning (DL) compiler, that en- ables data scientists to deploy models with popular frameworks such as TensorFlow and PyTorch with minimal code changes. However, the class of supported models was limited to relatively shallow networks with polynomial activations. Here, we introduce nGraph-HE2, which extends nGraph-HE to enable privacy-preserving inference on standard, pre-trained models using their...

Modular multiplication is one of the most compute-intensive arithmetic operations. Most public-key cryptosytems utilize modular multiplications of integers of various lengths, depending on security requirements. Efficient algorithms and implementations are required to realize a practical public-key cryptosystem. Different parameters, such as area, power and time, can be optimized for different implementation requirements. Low latency was not as important as high throughput requirement for...

The concrete efficiency of secure computation has been the focus of many recent works. In this work, we present concretely-efficient protocols for secure $3$-party computation (3PC) over a ring of integers modulo $2$^$l$ tolerating one corruption, both with semi-honest and malicious security. Owing to the fact that computation over ring emulates computation over the real-world system architectures, secure computation over ring has gained momentum of late. Cast in the offline-online...

Classical-style BFT protocols use two or more rounds of voting to confirm each block, e.g., in PBFT, they are called the “prepare” round and the “commit” round respectively. Recently, an elegant pipelining idea came out of the cryptocurrency community, i.e., if each block required two rounds of voting, why not piggyback the second round on the next block’s voting? We refer to this idea as the pipelined-BFT paradigm. We describe a simple partially synchronous blockchain protocol called PaLa...

Recently the CAESAR competition has announced several finalists among the submitted authenticated encryption algorithms, after an open selection process during the last 5 years. Applications using these algorithms are rapidly increasing today. Devices implementing these applications are enormously susceptible to physical attacks, which are able to retrieve secret data through side-channel information such as the power consumption or the electromagnetic radiations. In this work we present a...

Proof of Work (PoW), a fundamental blockchain protocol, has been widely applied and thoroughly testifed in various decentralized cryptocurrencies, due to its intriguing merits including trustworthy sustainability, robustness against sybil attack, delicate incentive-compatibility, and openness to any participant. Meanwhile, PoW-powered blockchains still suffer from poor efciency, potential selfsh mining, to-be-optimized fairness and extreme inconvenience of protocol upgrading....

While businesses shift their databases to the cloud, they continue to depend on them to operate correctly. Alarmingly, cloud services constantly face threats from exploits in the privileged computing layers (e.g. OS, Hypervisor) and attacks from rogue datacenter administrators, which tamper with the database's storage and cause it to produce incorrect results. Although integrity verification of outsourced storage and file systems is a well-studied problem, prior techniques impose prohibitive...

Existing proof-of-work cryptocurrencies cannot tolerate attackers controlling more than 50% of the network’s computing power at any time, but assume that such a condition happening is “unlikely”. However, recent attack sophistication, e.g., where attackers can rent mining capacity to obtain a majority of computing power temporarily, render this assumption unrealistic. This paper proposes RepuCoin, the first system to provide guarantees even when more than 50% of the system’s computing power...

Bitcoin, the first decentralized cryptocurrency, achieves great success but also encounters many challenges. In this paper, we mainly focus on Bitcoin's five challenges: low network synchronization; poor throughput; high information propagation delay; vulnerabilities to fork-based attacks and consumption of a large amount of computational power to maintain the blockchain. To address these challenges, we present the CP-consensus, a blockchain protocol based on synchronous timestamps of the...

Threshold Implementation (TI) is one of the most widely used countermeasure for side channel attacks. Over the years several TI techniques have been proposed for randomizing cipher execution using different variations of secret-sharing and implementation techniques. For instance, Direct Sharing (4-shares) is the most straightforward implementation of the threshold countermeasure. However, its usage is limited due to its high area requirements. On the other hand, sharing using decomposition...

Permissionless blockchains protocols such as Bitcoin are inherently limited in transaction throughput and latency. Current efforts to address this key issue focus on off-chain payment channels that can be combined in a Payment-Channel Network (PCN) to enable an unlimited number of payments without requiring to access the blockchain other than to register the initial and final capacity of each channel. While this approach paves the way for low latency and high throughput of payments, its...

We present the first hardware implementations of Diffie-Hellman key exchange based on the Kummer surface of Gaudry and Schost’s genus-2 curve targeting a 128-bit security level. We describe a single-core architecture for low-latency applications and a multi-core architecture for high-throughput applications. Synthesized on a Xilinx Zynq-7020 FPGA, our architectures perform a key exchange with lower latency and higher throughput than any other reported implementation using prime-field...

In this paper we describe how to couple reputation systems with distributed consensus protocols to provide high-throughput highly-scalable consensus for large peer-to-peer networks of untrusted validators. We introduce reputation module Guru, which can be laid on top of various consensus protocols such as PBFT or HoneyBadger. It ranks nodes based on the outcomes of consensus rounds run by a small committee, and adaptively selects the committee based on the current reputation. The protocol...

We introduce SPHINCS-Simpira, which is a variant of the SPHINCS signature scheme with Simpira as a building block. SPHINCS was proposed by Bernstein et al. at EUROCRYPT 2015 as a hash-based signature scheme with post-quantum security. At ASIACRYPT 2016, Gueron and Mouha introduced the Simpira family of cryptographic permutations, which delivers high throughput on modern 64-bit processors by using only one building block: the AES round function. The Simpira family claims security against...

Designing a secure permissionless distributed ledger that performs on par with centralized payment processors such as Visa is challenging. Most existing distributed ledgers are unable to "scale-out'' -- growing total processing capacity with number of participants -- and those that do compromise security or decentralization. This work presents OmniLedger, the first scale-out distributed ledger that can preserve long-term security under permissionless operation. OmniLedger ensures strong...

NSEC5 is a proposed modification to DNSSEC that guarantees two security properties: (1) privacy against offline zone enumeration, and (2) integrity of zone contents, even if an adversary compromises the authoritative nameserver responsible for responding to DNS queries for the zone. In this work, we redesign NSEC5 in order to make it practical and performant. Our NSEC5 redesign features a new verifiable random function (VRF) based on elliptic curve cryptography (ECC), along with a...

Simpira v2 is a family of cryptographic permutations proposed at ASIACRYPT 2016 which can be used to construct high throughput block ciphers using the Even-Mansour construction, permutation-based hashing and wide-block authenticated encryption. In this paper, we give a 9-round impossible differential of Simpira-4, which turns out to be the first 9-round impossible differential. In order to get some efficient key recovery attacks on its block cipher mode (EM construction with Simpira-4), we...

A growing body of research on Bitcoin and other permissionless cryptocurrencies that utilize Nakamoto's blockchain has shown that they do not easily scale to process a high throughput of transactions, or to quickly approve individual transactions; blocks must be kept small, and their creation rates must be kept low in order to allow nodes to reach consensus securely. As of today, Bitcoin processes a mere 3-7 transactions per second, and transaction confirmation takes at least several...

Software-based cryptographic implementations can be vulnerable to side-channel analysis. Masking countermeasures rank among the most prevalent techniques against it, ensuring formally the protection vs. value-based leakages. However, its applicability is halted by two factors. First, a masking countermeasure involves a computational overhead that can render implementations inefficient. Second, physical effects such as glitches and distance-based leakages can cause the reduction of the...

This paper presents high-throughput assembly implementations of PRESENT, PRINCE and KATAN64 ciphers for the ATtiny family of AVR microcontrollers. We report throughput records, achieving the speed of 2967 clock cycles per block encryption for PRESENT, 1803 cycles for PRINCE and 23671 cycles for KATAN64. In addition, we offer insight into the `slicing' techniques used for high throughput and their application to lightweight cryptographic implementations. We also demonstrate the speed-memory...

In this paper, we describe a new protocol for secure three-party computation of any functionality, with an honest majority and a \textit{malicious} adversary. Our protocol has both an information-theoretic and computational variant, and is distinguished by extremely low communication complexity and very simple computation. We start from the recent semi-honest protocol of Araki et al. (ACM CCS 2016) in which the parties communicate only a single bit per AND gate, and modify it to be secure in...

In this paper, we describe a new information-theoretic protocol (and a computationally-secure variant) for secure {\em three}-party computation with an honest majority. The protocol has very minimal computation and communication; for Boolean circuits, each party sends only a single bit for every AND gate (and nothing is sent for XOR gates). Our protocol is (simulation-based) secure in the presence of semi-honest adversaries, and achieves privacy in the client/server model in the presence of...

To the best of our knowledge, we present the first hardware implementation of isogeny-based cryptography available in the literature. Particularly, we present the first implementation of the supersingular isogeny Diffie-Hellman (SIDH) key exchange, which features quantum-resistance. We optimize this design for speed by creating a high throughput multiplier unit, taking advantage of parallelization of arithmetic in $\mathbb{F}_{p^{2}}$, and minimizing pipeline stalls with optimal scheduling....

This paper proposes a highly efficient AES hardware architecture that supports both encryption and decryption for the CBC mode. Some conventional AES architectures employ pipelining techniques to enhance the throughput and efficiency. However, such pipelined architectures are frequently unfit because many practical cryptographic applications work in the CBC mode, where block-wise parallelism is not available for encryption. In this paper, we present an efficient AES encryption/decryption...

This paper introduces Simpira, a family of cryptographic permutations that supports inputs of $128 \times b$ bits, where $b$ is a positive integer. Its design goal is to achieve high throughput on virtually all modern 64-bit processors, that nowadays already have native instructions for AES. To achieve this goal, Simpira uses only one building block: the AES round function. For $b=1$, Simpira corresponds to 12-round AES with fixed round keys, whereas for $b\ge 2$, Simpira is a Generalized...

A manufacturer of custom hardware (ASICs) can undermine the intended execution of that hardware; high-assurance execution thus requires controlling the manufacturing chain. However, a trusted platform might be orders of magnitude worse in performance or price than an advanced, untrusted platform. This paper initiates exploration of an alternative: using verifiable computation (VC), an untrusted ASIC computes proofs of correct execution, which are verified by a trusted processor or ASIC. In...

In this paper, we propose a new hardware friendly authen- ticated encryption (AE) scheme TriviA based on (i) a stream cipher for generating keys for the ciphertext and the tag, and (ii) a pairwise in- dependent hash to compute the tag. We have adopted one of the ISO- standardized stream ciphers for lightweight cryptography, namely Triv- ium, to obtain our underlying stream cipher. This new stream cipher has a state that is a little larger than the state of Trivium to accommodate a 128-bit...

Physical Unclonable Functions (PUFs) are specialized circuits with applications including key generation and challenge-response authentication. PUF properties such as low cost and resistance to invasive attacks make PUFs well-suited to embedded devices. Yet, given how infrequently the specialized capabilities of a PUF may be needed, the silicon area dedicated to it is largely idle. This inefficient resource usage is at odds with the cost minimization objective of embedded devices. Motivated...

In the last few years, several practitioners have proposed a wide range of approaches for reducing the implementation area of the AES in hardware. However, an area-throughput trade-off that undermines high-speed is not realistic for real-time cryptographic applications. In this manuscript, we explore how Genetic Algorithms (GAs) can be used for pipelining the AES substitution box based on composite field arithmetic. We implemented a framework that parses and analyzes a Verilog netlist,...

This paper introduces our dedicated authenticated encryption scheme ICEPOLE. ICEPOLE is a high-speed hardware-oriented scheme, suitable for high-throughput network nodes or generally any environment where specialized hardware (such as FPGAs or ASICs) can be used to provide high data processing rates. ICEPOLE-128 (the primary ICEPOLE variant) is very fast. On the modern FPGA device Virtex 6, a basic iterative architecture of ICEPOLE reaches 41 Gbits/s, which is over 10 times faster than the...

RC4 has remained the most popular software stream cipher since the last two decades. In parallel to cryptanalytic attempts, researchers have come up with many variants of RC4, some targeted to more security, some towards more throughput. We observe that the design of RC4 has been changed a lot in most of the variants. Since the RC4 structure is quite secure if the cipher is used with proper precautions, an arbitrary change in the design may lead to potential vulnerabilities, such as the...

Abstract.In this paper, we propose a high-throughput pipeline architecture of the stream cipher ZUC which has been included in the security portfolio of 3GPP LTE-Advanced. In the literature, the schema with the highest throughput only implements the working stage of ZUC. The schemas which implement ZUC completely can only achieve a much lower throughput, since a self-feedback loop in the critical path significantly reduces operating frequency. In this paper we design a mixed two-stage...

Introduced in 1996 and greatly developed over the last few years, Lattice-based cryptography oers a whole set of primitives with nice features, including provable security and asymptotic efficiency. Going from \asymptotic" to \real-world" efficiency seems important as the set of available primitives increases in size and functionality. In this present paper, we explore the improvements that can be obtained through the use of an FPGA architecture for implementing an ideal-lattice based...

The Galois configuration of Nonlinear Feedback Shift Registers (NLFSRs) is attractive for stream ciphers for which high throughput is very important. In this paper, we prove that any Galois NLFSR can be transformed into an equivalent NLFSR in the Fibonacci configuration, which is the conventional conguration of NLFSRs. The transformation is mentioned in the proof. The mapping between the initial states of the Galois NLFSR and its equivalent Fibonacci configuration is also derived. Moreover,...

Till date, the basic idea for implementing stream ciphers has been confined to individual standalone designs. In this paper, we introduce the notion of integrated implementation of multiple stream ciphers within a single architecture, where the goal is to achieve area and throughput efficiency by exploiting the structural similarities of the ciphers at an algorithmic level. We present two case studies to support our idea. First, we propose the merger of SNOW 3G and ZUC stream ciphers, which...

In this paper, we present an efficient FPGA implementation of the SHA-3 hash function candidate Shabal. Targeted at the recent Xilinx Virtex-5 FPGA family, our design achieves a relatively high throughput of 2 Gbit/s at a cost of only 153 slices, yielding a throughput-vs.-area ratio of 13.4 Mbit/s per slice. Our work can also be ported to Xilinx Spartan-3 FPGAs, on which it supports a throughput of 800 Mbit/s for only 499 slices, or equivalently 1.6 Mbit/s per slice. According to the SHA-3...

The National Institute of Standards and Technology (NIST) has started a competition for a new secure hash standard. To make a significant comparison between the submitted candidates, third party implementations of all proposed hash functions are needed. This is one of the reasons why the SHA-3 candidate Gr\{o}stl has been chosen for a FPGA-based implementation. Mainly our work is motivated by actual and future developments of the automotive market (e.g. car-2-car communication systems),...

As a result of extensive analyses on cryptographic hash functions, NIST started an open competition for selecting a new standard hash function SHA-3. One important aspect of this competition is in evaluating hardware implementations and in collecting much attention of researchers in this area. For a fair comparison of the hardware performance, we propose an evaluation platform, a hardware design strategy, and evaluation criteria that must be consistent for all SHA-3 candidates. First, we...

In this paper we describe our high-speed hardware implementations of the 14 candidates of the second evalution round of the \mbox{SHA-3} hash function competition. We synthesized all implementations using a uniform tool chain, standard-cell library, target technology, and optimization heuristic. This work provides the fairest comparison of all second-round candidates to date.

Hash functions are widely used in Cryptography, and hardware implementations of hash functions are of interest in a variety of contexts such as speeding up the computations of a network server or providing authentication in small electronic devices such as RFID tags. Provably secure hash functions, the security of which relies on the hardness of a mathematical problem, are particularly appealing for security, but they used to be too inefficient in practice. In this paper, we study the...

In~\cite{gscm}, GSCM mode of operation for authenticated encryption was presented. GSCM is based on the Galois/Counter Mode (GCM). GSCM is an enhancement of GCM, which is characterized by its high throughput and low memory consumption in network applications. In this paper, we propose some enhancements to GSCM and compare it with the different implementations of GCM. We present stability, performance, memory and security analyses of different implementations of GSCM and GCM.

Feedback with Carry Shift Registers (FCSRs) are a promising alternative to LFSRs in the design of stream cipher. The previous constructions based on FCSRs were dedicated to hardware applications. In this paper, we will describe X-FCSR a family of software oriented stream cipher using FCSRs. The core of the system is composed of two 256-bits FCSRs. We propose two versions: X-FCSR-128 and X-FCSR-256 which output respectively 128 and 256 bits at each iteration. We study the resistance of our...

Recently, there have been many proposals for secure and novel cryptographic protocols that are built on bilinear pairings. The $\eta_T$ pairing is one such pairing and is closely related to the Tate pairing. In this paper we consider the efficient hardware implementation of this pairing in characteristic 3. All characteristic 3 operations required to compute the pairing are outlined in detail. An efficient, flexible and reconfigurable processor for the $\eta_T$ pairing in characteristic 3 is...

Two alternative architectures and VLSI implementations of the 64-bit NESSIE proposal, MISTY1 block cipher, are presented in this paper. For these implementations, FPGA devices were used. The first architecture is suitable for applications with high throughput requirements. A throughput of up to 7.2 Gbps can be achieved at a clock frequency of 96 MHz. The main characteristic of this implementation is that uses RAM blocks that are embedded in the FPGA device in order to implement the necessary...

Low power consumption, low gate count and high throughput used to be standard design criteria for cryptographic coprocessors designated for smart cards and related embedded devices. Not anymore. With the advent of side channel attacks, the first and foremost concern is device resistance to such attacks. This paper describes how to to embed data masking technique at a hardware level for an AES coprocessor. We concentrate on inversion in the field since it is the only non-linear operation...