In order to overcome the disadvantages of poor security and lack of trust in the traditional electronic voting system and improve the reliability of the election system, this paper proposes an electronic voting system based on blockchain. This system is divided into voting module and blockchain management module, which mainly aims at the credibility of voting data and the protection of voters' privacy. The voting module begins with the verification of voter's identity, uses Zero Knowledge Proof algorithm to prove that the entrant is the legitimate owner of part of the rights and interests, uses ECDSA to encrypt the data, and uses Digital Signature to verify the security and integrity of the data. The main purpose of the blockchain management module is to update the data in real time, make the newly added nodes complete data synchronization, check the consistency of the data, and provide the user with historical records.
Igor A. Kalmykov, Ivan Dmitrievich Efremenkov, Dmitry Vladimirovich Yurdanov, М. И. Калмыков · 6 authors
At the present stage of development, in order to ensure the fulfillment of various kinds of tasks of national importance, systems based on groups of low-orbit communication spacecraft are increasingly being used. An example of such satellite systems is the Gonets Satellite System JSC, which provides mobile satellite channels for mobile and stationary subscribers anywhere in the world and is being developed by order of the Roskosmos state corporation for comic activities. Therefore, in view of the importance and in some cases the confidentiality of the tasks performed, the requirements for stealth and noise immunity for these systems are increasing. Increasing secrecy, namely, its information component, is possible through the use of an authentication protocol based on evidence with zero knowledge disclosure, which operates on the basis of modular codes. However, the modular codes in some systems are also used to combat equipment failures and malfunctions, and when introducing more redundancy, they are also able to localize errors caused by interference in the communication channel. Thus, using modular codes to ensure stealth, to combat failures and malfunctions, as well as to provide noise immunity, it will allow you to switch to a single mathematical apparatus for constructing the system and thereby move away from the traditionally used cascade codes. Therefore, the task of developing a new method for constructing a modular composite code to ensure noise immunity is relevant.
It has become a truism that the speed of technological progress leaves law and policy scrambling to keep up. But in addition to creating new challenges, technological advances also enable new improvements to issues at the intersection of law and technology. In this thesis, I develop new cryptographic tools for informing and improving our law and policy, including specific technical innovations and analysis of the limits of possible interventions. First, I present a cryptographic analysis of a legal question concerning the limits of the Fifth Amendment: can courts legally compel people to decrypt their devices? Our cryptographic analysis is useful not only for answering this specific question about encrypted devices, but also for analyzing questions about the wider legal doctrine. The second part of this thesis turns to algorithmic fairness. With the rise of automated decision-making, greater attention has been paid to statistical notions of fairness and equity. In this part of the work, I demonstrate technical limits of those notions and examine a relaxation of those notions; these analyses should inform legal or policy interventions. Finally, the third section of this thesis describes several methods for improving zero-knowledge proofs of knowledge, which allow a prover to convince a verifier of some property without revealing anything beyond the fact of the prover's knowledge. The methods in this work yield a concrete proof size reduction of two plausibly post-quantum styles of proof with transparent setup that can be made non-interactive via the Fiat-Shamir transform: "MPC-in-the-head," which is a linear-size proof that is fast, low-memory, and has few assumptions, and "Ligero," a sublinear-size proof achieving a balance between proof size and prover runtime. We will describe areas where zero-knowledge proofs in general can provide new, currently-untapped functionalities for resolving legal disputes, proving adherence to a policy, executing contracts, and enabling the sale of information without giving it away.
Open access
Cryptography and Data Security
Digital and Cyber Forensics
Physical Unclonable Functions (PUFs) and Hardware Security
Successful sharing of information-positive (actual) knowledge about facts, skills that are imparted, abilities developed and expressed-is the implicit goal of instruction in all its varied forms. It is the goal of training athletes, dancers, and professionals in every walk of life from early childhood to the most advanced level of education. PART ONE introduces mathematical proofs showing that the interactional successes engineered by instructors, other things being equal, must trend toward 100% shared information-mastery of the course of study. Failed efforts trend toward a complete absence of shared information. All this holds independently for the subject-matter, methods of instruction, and the attributes conducive to instructional success. In Part One, the underlying proofs are united by a very simple proof from the theory of true narratives showing that every iota of knowledge that might be shared in any instructional context depends on the kind of representations found in true reports of actual experience. Empirical studies in Part One confirm the predicted agreement in diverse contexts on the elements of good teaching. In Part Two, Kolmogorov's proofs from 1933 are generalized, amplified, and tested empirically showing successful instruction converging toward 100% agreement on 1) subject-matter, 2) which methods of presentation and assessment work, and even on 3) the abstract criteria for successful instruction. At the same time, as the proofs also show, the cumulative effects of failed communicative efforts must and do trend toward zero shared information.
This paper considers the problem of expanding a language class that can be proven by a non-interactive zero-knowledge proof system (NIZK) in a black-box manner in the common reference string model. Namely, given NIZKs for two languages,L0andL1, can we construct an NIZK forL0vL1in a black-box manner? NIZKs for disjunctive languages have a large number of applications, such as electronic voting. Therefore, such a black-box construction may enable the efficient constructions of such applications. However, Abe et al. (PKC 2020) showed that this is impossible if the two given NIZKs are simulation-sound. In this paper, we prove that it is also impossible if the two given NIZKs are constructed by the commit-and-prove methodology that is typically used in many cryptographic protocols, including NIZKs. This result suggests that if we want to augment the capability of NIZKs in terms of the languages they can prove, we should rely on certain properties or structures of the underlying NIZKs, such as algebraic structures.
Abstract It is well known that several cryptographic primitives cannot be achieved without a common reference string (CRS). Those include, for instance, non-interactive zero-knowledge for NP, or maliciously secure computation in fewer than four rounds. The security of those primitives heavily relies on the assumption that the trusted authority, who generates the CRS, does not misuse the randomness used in the CRS generation. However, we argue that there is no such thing as an unconditionally trusted authority and every authority must be held accountable for any trust to be well-founded. Indeed, a malicious authority can, for instance, recover private inputs of honest parties given transcripts of the protocols executed with respect to the CRS it has generated. While eliminating trust in the trusted authority may not be entirely feasible, can we at least move towards achieving some notion of accountability? We propose a new notion in which, if the CRS authority releases the private inputs of protocol executions to others, we can then provide a publicly-verifiable proof that certifies that the authority misbehaved. We study the feasibility of this notion in the context of non-interactive zero knowledge and two-round secure two-party computation.
Karim Baghery, Cyprien Delpech de Saint Guilhem, Emmanuela Orsini, Nigel P. Smart · 5 authors
This paper introduces M-Circuits, a program representation which generalizes arithmetic and binary circuits. This new representation is motivated by the way modern multi-party computation (MPC) systems based on linear secret sharing schemes actually operate. We then show how this representation also allows one to construct zero knowledge proof (ZKP) systems based on the MPC-in-the-head paradigm. The use of the M-Circuit program abstraction then allows for a number of program-specific optimizations to be applied generically. It also allows to separate complexity and security optimizations for program compilation from those for application protocols (MPC or ZKP).
Carmit Hazay, Muthuramakrishnan Venkitasubramaniam, Mor Weiss
Zero-Knowledge PCPs (ZK-PCPs; Kilian, Petrank, and Tardos, STOC `97) are PCPs with the additional zero-knowledge guarantee that the view of any (possibly malicious) verifier making a bounded number of queries to the proof can be efficiently simulated up to a small statistical distance. Similarly, ZK-PCPs of Proximity (ZK-PCPPs; Ishai and Weiss, TCC `14) are PCPPs in which the view of an adversarial verifier can be efficiently simulated with few queries to the input. Previous ZK-PCP constructions obtained an exponential gap between the query complexity q of the honest verifier, and the bound q^* on the queries of a malicious verifier (i.e., q = poly log (q^*)), but required either exponential-time simulation, or adaptive honest verification. This should be contrasted with standard PCPs, that can be verified non-adaptively (i.e., with a single round of queries to the proof). The problem of constructing such ZK-PCPs, even when q^* = q, has remained open since they were first introduced more than 2 decades ago. This question is also open for ZK-PCPPs, for which no construction with non-adaptive honest verification is known (not even with exponential-time simulation). We resolve this question by constructing the first ZK-PCPs and ZK-PCPPs which simultaneously achieve efficient zero-knowledge simulation and non-adaptive honest verification. Our schemes have a square-root query gap, namely q^*/q = O(√n) where n is the input length. Our constructions combine the "MPC-in-the-head" technique (Ishai et al., STOC `07) with leakage-resilient secret sharing. Specifically, we use the MPC-in-the-head technique to construct a ZK-PCP variant over a large alphabet, then employ leakage-resilient secret sharing to design a new alphabet reduction for ZK-PCPs which preserves zero-knowledge.
Proof-of-Work (PoW) is one of the fundamental and widely-used consensus algorithms in blockchains. In PoW, nodes compete to receive the mining reward by trying to be the first to solve a puzzle. Despite its fairness and wide-availability, traditional PoW incurs extreme computational and energy waste over the blockchain. This waste is considered to be one of the biggest problems in PoW-based blockchains and cryptocurrencies. In this work, we propose a new useful PoW called Proof-of-Useful-Randomness (PoUR) that mitigates the energy waste by incorporating pre-computed (disclosable) randomness into the PoW. The key idea is to inject special randomness into puzzles via algebraic commitments that can be stored and later disclosed. Unlike the traditional wasteful PoWs, our approach enables pre-computed commitments to be utilized by a vast array of public-key cryptography methods that require offline-online processing (e.g., digital signature, key exchange, zero-knowledge protocol). Moreover, our PoW preserves the desirable properties of the traditional PoW and therefore does not require a substantial alteration in the underlying protocol. We showed the security of our PoW, and then fully implemented it to validate its significant energy-saving capabilities.
Blockchain is a decentralized distributed ledger technology. The public chain represented by Bitcoin and Ethereum only realizes the limited anonymity of user identity, and the transaction amount is open to the whole network, resulting in user privacy leakage. Based on the existing anonymous technology, the concealment of the sender, receiver, amount of the transaction, and does not disclose any information, which makes the supervision difficult. Therefore, the design of blockchain scheme with privacy protection and supervision functions is of great significance. In this paper, a blockchain transaction model with both privacy and supervision function is proposed. It uses probability encryption to realize the hiding of the true identity of the blockchain transaction, and uses the commitment scheme and zero-knowledge proof technology to realize the privacy protection and guarantee legitimacy verification of the transaction. With the use of encryption technology, the regulators can supervise blockchain transactions without storing the users' information, which greatly reduces the pressure on storage, computing and key management. In addition, it does not rely on specific consensus mechanism and can be used as an independent module. The security performance analysis shows that the proposed scheme has great practicability and has potential application in many fields.