Kaixin Ma, Filip Ilievski, Jonathan Francis, Yonatan Bisk Ā· 6 authors
Recent developments in pre-trained neural language modeling have led to leaps in accuracy on common-sense question-answering benchmarks. However, there is increasing concern that models overfit to specific tasks, without learning to utilize external knowledge or perform general semantic reasoning. In contrast, zero-shot evaluations have shown promise as a more robust measure of a modelās general reasoning abilities. In this paper, we propose a novel neuro-symbolic framework for zero-shot question answering across commonsense tasks. Guided by a set of hypotheses, the framework studies how to transform various pre-existing knowledge resources into a form that is most effective for pre-training models. We vary the set of language models, training regimes, knowledge sources, and data generation strategies, and measure their impact across tasks. Extending on prior work, we devise and compare four constrained distractor-sampling strategies. We provide empirical results across five commonsense question-answering tasks with data generated from five external knowledge resources. We show that, while an individual knowledge graph is better suited for specific tasks, a global knowledge graph brings consistent gains across different tasks. In addition, both preserving the structure of the task as well as generating fair and informative questions help language models learn more effectively.
Vehicular crowd sensing is a promising approach to address the problem of traffic data collection by leveraging the power of vehicles. In various applications of vehicular crowd sensing, there exist two burning issues. First, privacy can be easily compromised when a vehicle is performing a crowd sensing task. Second, vehicles have no incentive to submit high-quality data due to the lack of fairness, which means that everyone gets the same paid, regardless of the quality of the submitted data. To address these issues, we propose a smart privacy-preserving incentive mechanism (SPPIM) for vehicular crowd sensing. Specifically, we first propose a new SPPIM model for the scenario of vehicular crowd sensing via smart contract on the blockchain. Then, we design a privacy-preserving incentive mechanism based on budget-limited reverse auction. Anonymous authentication based on zero-knowledge proof is utilized to ensure the privacy preservation of vehicles. To ensure fairness, the reward payments of winning vehicles are determined by not only the bids of vehicles but also their reputation and the data quality. Then, any rewarded vehicle can get the fair payment; on the contrary, malicious vehicles or task initiators will be punished. Finally, SPPIM is implemented by using smart contracts written via Solidity on a local Ethereum blockchain network. Both security analysis and experimental results show that the proposed SPPIM achieves privacy preservation and fair incentives at acceptable execution costs.
Leakage of private information has become a threat to the security of cryptography systems. It has become a common security requirement that a cryptography scheme should withstand various leakage attacks. The non-interactive zero-knowledge (NIZK) argument system, one-time lossy filter (OT-LF) and one-time signature were widely used to create the generic constructions of leakage-resilient identity-based encryption (IBE) scheme with chosen-ciphertext attack (CCA) security. However, the computational efficiency of the corresponding generic construction is low because the underlying cryptographic tool is low. Thus, to solve the above problem, a new cryptographic primitive, called identity-based hash proof system with two encapsulated-key (T-IB-HPS), is proposed. The new generic constructions of leakage resilient IBE scheme with CCA security is created from the T-IB-HPS and message authentication code (MAC), and the security of the above proposed scheme is proved from the security of the underlying cryptographic tool. To further show the practicability, an instantiation of T-IB-HPS is constructed, and the formal security proof of the above instantiation is shown based on the decisional bilinear Diffie-Hellman (DBDH) assumption. Compared with the previous generic constructions of leakage resilient IBE scheme with CCA security, since the underlying cryptographic tools with low computational efficiency are not used, our generic construction has high computational efficiency.
The ever-increasing demand for high communication data rate and high-quality multi-media services; over past few decades, has ignited new avenues in radio architectures. Frequency reconfigurable (or frequency agile) communication systems are among the key architectures for efficient and cost-effective utilization of the allotted frequency spectrum. The emerging concept of on-orbit flexible payload (or programmable payload) in satellite communication is another encouraging development on the horizon. In-addition, tunability in filters used for remote radio unit (RRU) is highly preferred by network operators owing to the high cost of installing RRU both in low density remotely accessed locations and in high density expensive urban locations. Such frequency reconfigurable radio architectures typically demand reconfigurability (tunability) of components within the physical layer as well. Hence, tunable filters play a vital role in realization of frequency reconfigurable communication systems. \n \nIn general, any fixed frequency filter can be transformed into a tunable filter by introducing tuning elements dedicated to tuning the resonators and the coupling structures. Thus, a tunable filter of order N would require 2N+1 tuning elements to maintain a constant absolute bandwidth (BW) over the tuning range. This use of large number of tuning elements not only increases size and cost, but also adds to the complexity of the tuning control mechanism, particularly when configured in a closed loop system. Over the past decade, a significant research has been carried out to reduce the number of tuning elements by roughly 50% (i.e. with only N tuning elements). The coupling structures are suitably designed to maintain their performance over the tuning range, eliminating N+1, while only N tuning elements are used for tuning the N resonators. The goal here is to further reduce the number of tuning elements to a āsingle tuning elementā. \n \nThe thesis presents several novel configurations for a high-Q tunable band pass filter employing a single tuning element, while maintaining a constant BW, return loss performance and location of the transmission zeros over a wide tuning range. Advanced filter synthesis techniques for both tunable filter and fixed filters are also proposed. \n \nA tunable double-septa waveguide (WG) filter is presented employing a single tuning element. The theory of coupling behavior of single septum and double septa to achieve constant absolute BW is explored. The tuning mechanism of the proposed filter is explained with measurement results presented for a Ku-band tunable WG filter designed at 15 GHz with a 2% fractional BW to achieve 15% tuning range. BW variation is observed to be within Ā±5% while the center frequency is tuned from 14.65 to 17.15 GHz. The filter promises to be useful in emerging 5G millimeter-wave applications, where the filter size is very small to accommodate multiple mechanical tuning elements. Furthermore, the proposed design methodology is scalable, i.e., the tuning mechanism is independent of the filter order. \n \nA frequency reconfigurable dual-mode WG filter having an elliptic response is presented. The proposed filter maintains a constant absolute BW and a constant rejection BW (i.e. constant frequency spacing between transmission zeros) over the tuning range. Furthermore, the filter can be tuned using a single tuning mechanism. A 4th order prototype filter at 11.5 GHz with 50 MHz bandwidth and 2 symmetric transmission zeros (Ā± 45 MHz) is fabricated and measured. \n \nA novel configuration of a BW reconfigurable WG filter that uses only two tuning elements irrespective of the filter order is proposed. The proposed filter configuration demonstrates that it can achieve a relatively wide BW variations without deviating the center frequency. A 4 pole prototype filter is designed, fabricated and tested at Ku-band. The measured BW tunability of the filter is nearly 35 % from 225 to 320 MHz at 13.375 GHz. To the authorās knowledge, this is the only BW reconfigurable filter that can be tuned with only two tuning elements regardless of the filter order. \n \nThe thesis also demonstrates the feasibility of realizing a high-Q lambda/2 resonator based tunable coaxial filter, which is tuned by a single rotational tuning element irrespective of the filter order. The proposed filter has low variations in the absolute BW and insertion loss (IL) over a relatively wide tuning range. A prototype four-pole filter is developed at 2.5 GHz with a fractional BW of 4% to verify the concept. The measured tuning range of the filter is 20%, within which the BW variation is better than Ā±10% and IL variation is better than 0.05 dB. The proposed concept is easily expandable to filters with higher order. Furthermore, the concept is adopted to design a tunable diplexer using only a single tuning mechanism while maintaining the frequency performance of each channel and the frequency spacing between the two channels over the tuning range. The proposed high-Q tunable filter is promising for use in the frequency-agile communication architecture at the cellular base-station and aerospace applications. \n \nA novel configuration of a High-Q coaxial tunable filter which employs a single rotational mechanism to tune the filter, while using fixed lambda/4 resonators is also presented. The rotational tuning concept is different from that proposed for the tunable coaxial lambda/2 resonators. A prototype filter is designed for the proof of concept, which has a tuning range of 11.6% from 685 MHz to 770 MHz, over which bandwidth variation is within 10.5Ā±0.7 MHz.. In-addition, the proposed design methodology can be scaled to realize higher order filters. The proposed filter promises to be useful in a wide range of telecommunication applications including flexible payload in aerospace applications.
Hazay, Carmit, Venkitasubramaniam, Muthuramakrishnan, Weiss, Mor
Leakage-resilient cryptography aims to protect cryptographic primitives from so-called "side channel attacks" that exploit their physical implementation to learn their input or secret state. Starting from the works of Ishai, Sahai and Wagner (CRYPTO`03) and Micali and Reyzin (TCC`04), most works on leakage-resilient cryptography either focus on protecting general computations, such as circuits or multiparty computation protocols, or on specific non-interactive primitives such as storage, encryption and signatures. This work focuses on leakage-resilience for the middle ground, namely for distributed and interactive cryptographic primitives. Our main technical contribution is designing the first secret-sharing scheme that is equivocal, resists adaptive probing of a constant fraction of bits from each share, while incurring only a constant blowup in share size. Equivocation is a strong leakage-resilience guarantee, recently introduced by Hazay et al. (ITC`21). Our construction is obtained via a general compiler which we introduce, that transforms any secret-sharing scheme into an equivocal scheme against adaptive leakage. An attractive feature of our compiler is that it respects additive reconstruction, namely, if the original scheme has additive reconstruction, then the transformed scheme has linear reconstruction. We extend our compiler to a general paradigm for protecting distributed primitives against leakage, and show its applicability to various primitives, including secret sharing, verifiable secret sharing, function secret sharing, distributed encryption and signatures, and distributed zero-knowledge proofs. For each of these primitives, our paradigm transforms any construction of the primitive into a scheme that resists adaptive party corruptions, as well as adaptive probing leakage of a constant fraction of bits in each share when the share is stored in memory (but not when it is used in computations). Moreover, the transformation incurs only a constant blowup in the share size, and respects additive reconstruction - an important feature for several of these primitives, such as function secret sharing and distributed encryption.
Jan Lauinger, Jens Ernstberger, Emanuel Regnath, Mohammad Hamad Ā· 5 authors
Self-sovereign Identity Management (SSIM) pro-motes self-control of credentials without relying on external administration. However, the state-of-the-art SSIM based on Decentralized Identifiers and Verifiable Credentials (VCs) defined by the World Wide Web Consortium does not enable credential holders to verify whether a Credential Issuing Authority (CIA) legitimately issued a credential.As a remedy, our work constructs a secure authentication protocol, called A-PoA, to provide decentralized and anonymous authorization of CIAs. We leverage a cryptographic accumulator to enable the Root Authority (registering a Credential Schema) with the ability to authorize a CIA (registering a Credential Definition) to issue a credential. The proof of accumulator membership relies on a non-interactive zero-knowledge proof. This allows a credential holder or validator node to verify the validity of a CIA, while the CIA remains anonymous. Our security analysis shows the integrity and confidentiality of our protocol against hostile network participants and our experimental evaluation shows constant verification times independent of the number of authenticated CIAs. Hence, A-PoA introduces the missing building block to develop SSIM-capable and VC-compatible ecosystems acting as a drop-in replacement for traditional Public Key Infrastructure schemes.
Platooning technologies enable trucks to drive cooperatively and automatically, which bring benefits including less fuel consumption, more road capacity and safety. In order to establish trust during dynamic platoon formation, ensure vehicular data integrity, and guard platoons against potential attackers, it is pivotal to verify any given vehicle's identity information before granting it access to join a platoon. To address this concern in dynamic truck platooning, we present a novel location-aware and privacy-preserving verification protocol based on zero-knowledge proof and permissioned blockchain. By performing the verification process within the spatially-local area defined by a given platoon, our system can provide lower latency and communication overhead compared to a location-agnostic blockchain system. We prototype the proposed system and perform benchmark tests on the Hyperledger platform. The experimental results show that our system is suitable for real-world truck platooning.
The total number of photovoltaic power producing facilities whose FIT-based ten-year contract expires by 2023 is expected to reach approximately 1.65 million in Japan. If the number of renewable electricity-producing/consuming facilities reached two million, an enormous number of transactions would be invoked beyond blockchain's scalability.We propose mutually cooperative two novel methods to simultaneously solve scalability, data size, and privacy problems in blockchain-based trading platforms for renewable energy environmental value. One is a management scheme of electricity production resources (EPRs) using an extended UTXO token. The other is a data aggregation scheme that aggregates a significant number of smart meter records with evidentiality using zero-knowledge proof (ZKP).
Blockchain is a technology that enables trust-based consensus and verification based on a decentralized network. Distributed ID (DID) is based on a decentralized structure, and users have the right to manage their own ID. Recently, interest in self-sovereign identity authentication is increasing. In this paper, as a method for transparent and safe sovereignty management of data, among data pseudonymization techniques for blockchain use, various methods for data encryption processing are examined. The public key technique (homomorphic encryption) has high flexibility and security because different algorithms are applied to the entire sentence for encryption and decryption. As a result, the computational efficiency decreases. The hash function method (MD5) can maintain flexibility and is higher than the security-related two-way encryption method, but there is a threat of collision. Zero-knowledge proof is based on public key encryption based on a mutual proof method, and complex formulas are applied to processes such as personal identification, key distribution, and digital signature. It requires consensus and verification process, so the operation efficiency is lowered to the level of O (logeN) ~ O(N2). In this paper, data encryption processing for blockchain DID, based on zero-knowledge proof, was proposed and a one-way encryption method considering data use range and frequency of use was proposed. Based on the content presented in the thesis, it is possible to process corrected zero-knowledge proof and to process data efficiently.
Access control is a fundamental keystone in security. Damgard, Haagh, and Orlandi (TCC 2016) introduced accessĖ control encryption (ACE) that enforces no-read and no-write rules without revealing the senders, receivers, or the content of the encrypted traffic. Existing designs of ACE for arbitrary policy (covering all possibilities of read/write relationship) rely on indistinguishability obfuscation or lattice-based assumptions, with either exponential-size ciphertexts or circuit realization of policy. Also, their designs mandate a private sanitizer key to remain perpetually online for sanitization. The only existing scheme that can afford a public sanitizer key supports only simple policies. To summarize, state-of-the-art ACE schemes only feature at most two of the following desirable properties: arbitrarypolicy, constant-size (ciphertext), and efficient (sanitization). This paper introduces an ACE scheme for arbitrary policy without sanitizer key, which solves the open question posed by Kim and Wu (Asiacrypt 2017). We also put forth the notion of cross-domain ACE, separating the key generator into the sender-authority and receiver-authority. Our scheme requires structure-preserving signatures, non-interactive zero-knowledge proof, and sanitizable identity-based broadcast encryption as the building blocks. It can be instantiated directly from pairing-based assumptions and features constant ciphertext size. We also prototyped our scheme and demonstrated its practical efficiency.
In this work, we design and implement the first protocol for distributed generation of an RSA modulus that can support thousands of parties and offers security against active corruption of an arbitrary number of parties. In a nutshell, we first design a highly optimized protocol for this scale that is secure against passive corruptions, and then amplify its security to withstand active corruptions using lightweight succinct zero-knowledge proofs. Our protocol achieves security with "identifiable abort," where a corrupted party is identified whenever the protocol aborts, and supports public verifiability.Our protocol against passive corruptions extends the recent work of Chen et al. (CRYPTO 2020) that, in turn, is based on the blueprint introduced in the original work of Boneh-Franklin protocol (CRYPTO 1997, J. ACM, 2001). Specifically, we reduce the task of sampling a modulus to secure distributed multiplication, which we implement via an efficient threshold additively homomorphic encryption scheme based on the Ring-LWE assumption. This results in a protocol where the (amortized) per-party communication cost grows logarithmically in the number of parties. In order to minimize the work done by the parties, we employ a "publicly verifiable" coordinator that is connected to all parties and only performs computations on public data.We implemented both the passive and the active variants of our protocol and ran experiments using 2 to 4,000 parties. This is the first implementation of any MPC protocol that can scale to more than 1,000 parties. For generating a 2048-bit modulus among 1,000 parties, our passive protocol executed in under 6 minutes and the active variant ran in under 25 minutes.
N. Suganthi, Gokul Sridharan, E Shravanth, K. Veena
Abstract: Democratic rule is based on safe and open electoral systems that can preserve their authenticity. The conventional voting processes are hampered significantly by electoral fraud and security breaches as well as centralized management and inefficiencies in auditability and accessibility. The issues of electoral systems reduce public trust along with lowering the credibility of election results. This paper introduces a new three-tier blockchain-based e-voting system designed to enhance voter privacy alongside system scalability and end-to-end verifiability to restore trust in electoral processes. Voter verification at Layer 1 (Identity Verification) combines Decentralized Identity (DID) with Zero-Knowledge Proofs (ZKP) and multimodal biometric techniques involving fingerprint scanning, facial recognition technology, and voice analysis. The system enables only the participation of valid voters while also protecting their private data and fulfilling different user needs. The system's Layer 2 (Vote Casting & Secure Storage) employs a hybrid consensus algorithm combining Byzantine Fault Tolerance (BFT) and Delegated Proof-of-Stake (dPoS) to store votes securely while reducing energy consumption. The system leverages Triple-Blind Signatures to provide complete voter anonymity by decoupling voter identities from their votes as well as any accompanying metadata. Lattice-based post-quantum cryptography is employed to encrypt votes which are distributed across sharded blockchain subnets for enhanced performance without sacrificing fault tolerance. The system accumulates votes via Merkle roots and verifies them via zk-SNARKs in Layer 3 (Result Processing & Transparency) that allows public observation without compromising voter privacy. A Live Audit Dashboard provides voters with the capability to check their vote in real time which facilitates transparent and accountable voting processes. The suggested system attains a secure and open electronic voting process using sophisticated cryptographic protocols in a decentralized setup compliant with international requirements while enabling digital democratic participation.
David Heath, Yibin Yang, David Devecsery, Vladimir Kolesnikov
We build a complete and efficient ZK toolchain that handles proof statements encoded as arbitrary ANSI C programs.Zero-Knowledge (ZK) proofs are foundational in cryptography. Recent ZK research has focused intensely on non-interactive proofs of small statements, useful in blockchain scenarios. We instead target large statements that are useful, e.g., in proving properties of programs.Recent work (Heath and Kolesnikov, CCS 2020 [HK20a]) designed an efficient proof-of-concept ZK machine (ZKM). Their machine executes arbitrary programs over a minimal instruction set, authenticating in ZK the program execution. In this work, we significantly extend this research thrust, both in terms of efficiency and generality. Our contributions include:ā¢ A rich and performance-oriented architecture for representing arbitrary ZK proofs as programs.ā¢ A complete compiler toolchain providing full support for ANSI C95 programs. We ran off-the-shelf buggy versions of the Linux programs sed and gzip, proving in ZK that each program has a bug. To our knowledge, this is the first ZK system capable of executing standard Linux programs.ā¢ Improved ZK oblivious RAM (ORAM). [HK20a] introduced an efficient ZK-specific ORAM BubbleRAM that consumes O(log2n) communication per access. We extend BubbleRAM with multi-level caching, decreasing communication to O(log n) per access. This introduces the possibility of a cache miss, which we handle cheaply. Our experiments show that cache misses are rare; in isolation, i.e., ignoring other processor costs, BubbleCache improves communication over BubbleRAM by more than 8Ć. Using BubbleCache improves our processorās total communication (including costs of cache misses) by ā 25-30%.ā¢ Numerous low-level optimizations, resulting in a CPU that is both more expressive and ā 5.5Ć faster than [HK20a]ās.ā¢ Attention to user experience. Our engineer-facing ZK instrumentation and extensions are minimal and easy to use.Put together, our system is efficient and general, and can run many standard Linux programs. The resultant machine runs at up to 11KHz on a 1Gbps LAN and supports MBs of RAM.
As pass the three revised bills, the Personal Information Protection Act was revised to have a larger application for personal information. For an industrial development through an efficient and secure usage of personal information, there is a need to revise the existing anonymity processing method. This paper modifies the Zero Knowledge Proofs algorithm among the anonymity processing methods to modify the anonymity process calculations by taking into account the reliability of the used service company. More detail, the formula of ZKP (Zero Knowledge Proof) used by ZK-SNAKE is used to modify the personal information for pseudonymization processing. The core function of the proposed algorithm is the addition of user variables and adjustment of the difficulty level according to the reliability of the data user organization and the scope of use. Through Setup_p, the additional variable Ī³ can be selectively applied according to the reliability of the user institution, and the degree of agreement of Witness is adjusted according to the reliability of the institution entered through Prove_p. The difficulty of the verification process is adjusted by considering the reliability of the institution entered through Verify_p. SimProve, a simulator, also refers to the scope of use and the reliability of the input authority. With this suggestion, it is possible to increase reliability and security of anonymity processing and distribution of personal information.
Efficient zero-knowledge (ZK) proofs for arbitrary boolean or arithmetic circuits have recently attracted much attention. Existing solutions suffer from either significant prover overhead (i.e., high memory usage) or relatively high communication complexity (at least Īŗ bits per gate, for computational security parameter Īŗ). In this paper, we propose a new protocol for constant-round interactive ZK proofs that simultaneously allows for an efficient prover with asymptotically optimal memory usage and significantly lower communication compared to protocols with similar memory efficiency. Specifically:ā¢The prover in our ZK protocol has linear running time and, perhaps more importantly, memory usage linear in the memory needed to evaluate the circuit non-cryptographically. This allows our proof system to scale easily to very large circuits.ā¢for statistical security parameter Ļ = 40, our ZK protocol communicates roughly 9 bits/gate for boolean circuits and 2ā4 field elements/gate for arithmetic circuits over large fields.Using 5 threads, 400 MB of memory, and a 200 Mbps network to evaluate a circuit with hundreds of billions of gates, our implementation (Ļ = 40, Īŗ = 128) runs at a rate of 0.45 Ī¼s/gate in the boolean case, and 1.6 Ī¼s/gate for an arithmetic circuit over a 61-bit field.We also present an improved subfield Vector Oblivious Linear Evaluation (sVOLE) protocol with malicious security that is of independent interest.
Digital signatures and key exchange protocols are the two most important public key cryptographic primitives used in the electronic transmission of data. The goal of key exchange is to preserve the secrecy of the communication, while the goal of digital signatures is to guarantee the authenticity of the exchanged messages. Constructions of digital signature schemes based on classical mathematical assumptions appeared shortly following the invention of public key cryptography in the late 1970s. And just like with key exchange, the most efficient variants are based on number-theoretic problems that are believed to be (sub)-exponentially hard for classical machines, but are solved in polynomial time by Shorās algorithm on a powerful-enough quantum computer. Also, like for key exchange, the most efficient constructions that we believe to be quantum safe are based on the presumed hardness of lattice problems over polynomial rings. One interesting difference between key exchange and digital signatures is that key exchange appears to inherently require that some mathematical problem be computationally hard. Digital signatures, on the other hand, can be generically constructed from any one-way function [1,2]. So even though they certainly fall into the category of public key primitives based on their usage, their existence requires much weaker assumptions. Additionally, the transformation from a one-way function to a digital signature is not too inefficient. For example, the total parameter size (public key + signature) of the SPHINCS+ scheme [3] is around 40 kB. While these sizes are larger, and signing times considerably longer, than those of signatures based on factoring or discrete log, it is still a usable scheme for many applications. And being only based on symmetric assumptions (e.g. one wayness and collision resistance of cryptographic hash functions), its security is very attractive. In order to be considered an interesting alternative to the above-mentioned signature, a scheme based on a mathematical assumption would need to have significant performance advantages. Schemes based on factoring and the discrete logarithm problem were significantly shorter and faster, and so the generic approach lay dormant for over four decades. The new quantum-safe schemes will need to have similar performance advantages if they are to be used in lieu of this safe approach. Below, we describe two techniques for constructing lattice-based digital signatures with output sizes being just a few kilobytes. On a very high level, lattice-based signature constructions follow the two known approaches for constructing classical signatures. In the first approach, the signer outputs a function f and an image y = f(x) as his public key and keeps x as his secret key. To sign a message Ī¼, he gives a non-interactive zero-knowledge proof that he knows an x satisfying y = f(x), using the message Ī¼ to create the āchallengeā H(Ī¼) for the proof (where H is a public function that maps Ī¼ to something ārandom lookingā). If the function f is one way then the verifier should be convinced that the proof could have only been created by the entity who knows x. A classic example of this type of scheme is the Schnorr signature scheme [4] based on the hardness of the discrete logarithm problem. The second approach is to create a function f together with a trapdoor fā1, output f as the public key and keep fā1 as the secret key. A message Ī¼ is signed by using the secret trapdoor to create a pre-image x such that f(x) = H(Ī¼). Again, if the function f is one way then only someone in possession of a trapdoor should be able to invert it. An example of such a construction based on a āfactoring-likeā assumption is the RSA signature scheme [5]. The high-level ideas for lattice-based signatures follow the above blueprints, but the technical details are significantly more involved. The main reason for the complications is the different algebraic structure of the hard one-way function underlying lattice cryptography. While the domain of the function in discrete log and RSA-based one-way functions are groups, the domains in lattice-based signatures are sets that are not closed under any operationāin particular, they are elements in a group that have small norms. This crucial small norm requirement precludes us from using uniformly random masking as in Schnorr signatures or having a trapdoor for a bijective one-way function as in RSA signatures. These barriers have, nevertheless, been overcome and the resulting digital signatures are quite practical. In 2017, the US National Institute of Standards and Technology (NIST) began a ācompetitionā for a quantum-safe key exchange and digital signatures standard. At the time of this writing, this process is in the third round and there are two lattice-based signatures remainingāeach following one of the above high-level designs. The CRYSTALS-Dilithium [6] scheme follows the Schnorr framework, but adds a crucial rejection-sampling step to keep the size of the coefficients small. The FALCON scheme [7] utilizes a randomized trapdoor sampling technique that uses a secret trapdoor for fā1 to produce random pre-images from a particular distribution. Because there is no longer a bijection, it is crucial to also have the property that the distribution of the outputted pre-images does not leak information about the trapdoor. Both schemes are relatively fast and their parameters (public key + signature size) are the shortest of all quantum-safe signature schemes. While both schemes are based on lattices, they have rather different characteristics. FALCON has very short parameters (see Table 1), but entails a rather complicated procedure for signature generation. In particular, it uses (an optimized version of) the GPV sampler [8], which requires floating-point arithmetic with approximately 64 bits of precision. Requiring such high precision means that subtle implementation errors may not get detected even with rigorous testing. Dilithium, on the other hand, has larger parameters but a very simple implementation where all the sampling in the signing is done in a power-of-2 range; it is thus much less prone to implementation errors. It is quite possible that in the future both schemes will be used for different applications. Approximate parameter sizes (in bytes) for the CRYSTALS-Dilithium and FALCON digital signature schemes at approximately 128-bit security levels. Approximate parameter sizes (in bytes) for the CRYSTALS-Dilithium and FALCON digital signature schemes at approximately 128-bit security levels. Conflict of interest statement. None declared.
In the field of modern bidding, electronic bidding leads a new trend of development, convenience and efficiency and other significant advantages effectively promote the reform and innovation of Chinaās bidding field. Nowadays, most systems require a strong and trusted third party to guarantee the integrity and security of the system. However, with the development of blockchain technology and the rise of privacy protection, researchers has begun to emphasize the core concept of decentralization. This paper introduces a decentralized electronic bidding system based on blockchain and smart contract. The system uses blockchain to replace the traditional database and uses chaincode to process business logic. In data interaction, encryption techniques such as zero-knowledge proof based on graph isomorphism are used to improve privacy protection, which improves the anonymity of participants, the privacy of data transmission, and the traceability and verifiable of data. Compared with other electronic bidding systems, this system is more secure and efficient, and has the nature of anonymous operation, which fully protects the privacy information in the bidding process.
Sidra Malik, Volkan Dedeoglu, Salil S. Kanhere, Raja Jurdak
Blockchain offers traceability and transparency to supply chain event data and hence can help overcome many challenges in supply chain management such as: data integrity, provenance and traceability. However, data privacy concerns such as the protection of trade secrets have hindered adoption of blockchain technology. Although consortium blockchains only allow authorised supply chain entities to read/write to the ledger, privacy preservation of trade secrets cannot be ascertained. In this work, we propose a privacy-preservation framework, PrivChain, to protect sensitive data on blockchain using zero knowledge proofs. PrivChain provides provenance and traceability without revealing any sensitive information to end-consumers or supply chain entities. Its novelty stems from: a) its ability to allow data owners to protect trade related information and instead provide proofs on the data, and b) an integrated incentive mechanism for entities providing valid proofs over provenance data. In particular, PrivChain uses Zero Knowledge Range Proofs (ZKRPs), an efficient variant of ZKPs, to provide origin information without disclosing the exact location of a supply chain product. Furthermore, the framework allows to compute proofs and commitments off-line, decoupling the computational overhead from blockchain. The proof verification process and incentive payment initiation are automated using blockchain transactions, smart contracts, and events. A proof of concept implementation on Hyperledger Fabric reveals a minimal overhead of using PrivChain for blockchain enabled supply chains.
Abstract A nominative signature (NS) is a cryptographic primitive where two parties collude to produce a signature. It is a user certification system and has applications in a variety of sectors where nominee cannot trust heavily on the nominator to validate the nominee's certificate and only targeted entities are allowed to verify the signature on sensitive data. A new construction for NS from standard assumptions on lattice is provided. The authorsā construction relies on collisionāresistant preimage sampleable function and symmetric key primitives like collisionāresistant pseudorandom function and zero knowledge proof system ZKB ++ for Boolean circuits. The authors provide detailed security analysis and show that their construction achieves security under unforgeability , invisibility , impersonation , and nonārepudiation in the existing model. Furthermore, our construction exhibits nonātransferability . The security under nonārepudiation is achieved in the quantum random oracle model using Unruh transform to ZKB ++ .
As autonomous vehicles fill the roads and more manufacturers join the trend, the need for a unified communication protocol grows. Current paradigms in vehicle-to-vehicle communication are too slow to provide accurate and meaningful traffic data in a timely fashion, and it is difficult to trust that incoming data is correct without an authoritative server verifying the sender's identity. This paper introduces a protocol for peer-to-peer exchanges of positional data that determines the trust level of a particular message by comparing matching object data hashes. Similar in concept to non-interactive zero-knowledge proofs, the design retains the privacy and anonymity of senders and is relatively fast compared to certificate-based solutions under a reasonable traffic load. Our preliminary experiment shows promising results, with much faster runtimes compared to similar cryptographic solutions. Although the current implementation is still rough around the edges, the basic design can provide the groundwork for future paradigms in inter-vehicular communication without depending on expensive cryptographic operations performed on special or more powerful hardware. This opens doors for protocols that can be run on current vehicles without requiring the collective processing power of all vehicles to increase.
Despite a considerable progress in verification of random and control logic, advances in formal verification of arithmetic designs have been lagging. This can be attributed mostly to the difficulty of efficient modeling of arithmetic circuits and data paths without resorting to computationally expensive Boolean methods, such as Binary Decision Diagrams (BDDs) and Boolean Satisfiability (SAT) that require ``bit blasting'', i.e., flattening the design to a bit-level netlist. Similarly, approaches that rely on computer algebra and Satisfiability Modulo Theories (SMT) methods are either too abstract to handle the bit-level complexity of arithmetic designs or require solving computationally expensive decision or satisfiability problems. On the other hand, theorem provers, popular solvers used in industry, require a significant human interaction and intimate knowledge of the design to guide the proof process. The work proposed in this thesis aims at overcoming the limitations of verifying arithmetic circuits, especially at the post-synthesis, implementation phase. It addresses the verification problem at an algebraic level, treating an arithmetic circuit and its specification as an algebraic system. Specifically, verification approach employed in this work is based on the algebraic rewriting method. In this method, the circuit is modeled in the algebraic domain, where both the circuit specification and its gate-level implementation are represented as polynomials. This work formally analyzes the algebraic approach and compares it with the established computer algebra methods based on Grobner basis reduction. It shows that algebraic rewriting is more effective than the Grobner basis reduction from the computational point of view. This thesis addresses two classes of arithmetic circuits that could not directly benefit from this type of functional verification, since performing algebraic rewriting of such circuits encounters a serious memory issue. The circuits that fall in the first category are approximate arithmetic circuits, such as truncated integer multipliers. Different truncation schemes are considered, including bit deletion, bit truncation, and rounding. The proposed verification method is based on reconstructing the truncated multiplier to a complete, exact multiplier; it is then followed by algebraic rewriting to prove that it indeed implements multiplication over the required range of bits. The reconstruction of the multiplier helps avoid the memory overload issue as it creates a "clean" multiplier with a well defined specification polynomial. The other class of circuits that suffer from memory overload during algebraic rewriting are circuits subjected to some arithmetic constraints. An example of such circuits is a divider, where the divisor value cannot be zero. The other example can be found in the basic blocks of the constant divider, where the value of carry into each block must be less than the divisor value. In general, such constraints will be modeled using the concept of vanishing monomials. A case-splitting method is proposed along with the modified algebraic rewriting to resolve the memory issue. The proposed verification method not only can prove that the circuit performs a correct function under the desired (valid) conditions, but also will test all the undesired (invalid) cases. This work also addresses logic debugging of combinational arithmetic circuits over field F<sub>2<sup>k</sup></sub> , including Galois field multipliers. Galois Field (GF) arithmetic has numerous applications in digital communication, cryptography and security engineering, and formal verification of such circuits is of prime importance. In addition to functional verification of GF multipliers, this work proposes a novel and effective method for identifying and correcting bugs in such circuits, commonly referred to as debugging. In this work we propose a novel approach to debugging of GF arithmetic circuits based on forward rewriting, which enables functional verification and debugging at the same time. This technique can handle multiple bugs, does not suffer from the polynomial size explosion encountered by other methods, and allows one to identify and automatically correct bugs in GF circuits. The techniques and algorithms proposed in this dissertation have been implemented in several computer programs, some stand-alone, and some integrated with a popular synthesis and verification tool, ABC. The experimental results for verification and debugging are compared with the state-of-the-art SAT, SMT, and other computer algebraic solvers.
The increasing adoption of multi-cloud computing has created new opportunities for improving resource utilization, service reliability, and reducing dependence on a single cloud provider. However, the distributed nature of multi-cloud infrastructures introduces significant challenges in maintaining data security, privacy, and continuous service availability. This study presents a dynamic security framework designed for multi-cloud environments that integrates adaptive monitoring with a multi-layer encryption mechanism. The proposed approach intelligently selects suitable encryption techniques based on data sensitivity, file size, and available computing resources to achieve an optimal balance between security and performance. The framework Dynamic Resource Management Algorithm(DRMA) for secure key establishment, efficient symmetric encryption for protecting data, and zero-knowledge proof-based authentication to ensure secure user verification without revealing sensitive information. A comprehensive performance evaluation was conducted by comparing the proposed model with conventional RSA-based security approaches. Experimental results demonstrate improved computational efficiency, reduced encryption overhead, enhanced scalability, and stronger protection against unauthorized access. Furthermore, the framework provides resilience against both conventional cyberattacks and emerging quantum computing threats while maintaining efficient resource utilization. These findings indicate that the proposed solution offers a practical and secure approach for protecting data and improving the reliability of modern multi-cloud environments.