Zero-knowledge proof system is an important protocol that can be used as a basic block for construction of other more complex cryptographic protocols.An intrinsic characteristic of a zeroknowledge systems is the assumption that is impossible for the verifier to show to a third part that he has interacted with the prover.However, it has been shown that using quantum correlations the impossibility of transferring proofs can be successfully attacked.In this work we show two new protocols for proof transference, being the first one based on teleportation and the second one without using entangled states. 1
Zero-knowledge proof system is an important protocol that can be used as a basic block for construction of other more complex cryptographic protocols.An intrinsic characteristic of a zeroknowledge systems is the assumption that is impossible for the verifier to show to a third part that he has interacted with the prover.However, it has been shown that using quantum correlations the impossibility of transferring proofs can be successfully attacked.In this work we show two new protocols for proof transference, being the first one based on teleportation and the second one without using entangled states. 1
The use of quantum correlations to attack security protocols is an important research line deserving growing attention. An important class of cryptographic protocols used as building blocks for several other more complex protocols is zero-knowledge proof systems. One of the properties that zero-knowledge proof systems are assumed to satisfy is that it is impossible for the verifier to show to a third party that he has interacted with the prover (impossibility of transferring proofs). Herein, it is shown how Bell pairs, together with tamper-proofing, can be used to break the impossibility of transferring proofs for an important class of zero-knowledge proof systems.
A Zero-Knowledge Proof basically is a protocol between two parties, the Prover and the Verifier, that allows the Prover to convince the Verifier about the truthness of a non trivial statement without revealing any additional information. Zero Knowledge Proofs have found a lot of practical applications covering most of the protocols concerning about data privacy and protocol verification. Examples of that are anonymous cash or electronic voting. The possibility to have real quantum computers with a reasonable size in a near future is forcing the cryptographic community to devise new methods to provide security that resist quantum attacks. Most of the zero-knowledge protocols used nowadays are based on computational problems like the discrete logarithm problem that can no longer be considered hard, since there are known efficient ways to solve them with quantum algorithms. Cryptographic research about the quantum security of zero knowledge proofs started nearly 20 years ago in a very theoretical approach, but not many papers on that topic appeared since then. The goal of this thesis is writing a survey including the main concepts about quantum secure zero-knowledge protocols, the state-of-the-art both from the theoretical and practical approaches, and an exploration of their potential application areas. The survey will be a good starting document for further students willing to do research in this topic.
This work presents a new scheme based on a quantum zero-knowledge proof for identity authentication. The novelty of this research is the migration of the classical concept Zero-knowledge into the quantum cryptographic framework that, to the best of our knowledge, has never been explored. This approach allows us to take advantage of the principles of quantum mechanics to build a protocol, which is secure against quantum computer attacks, for authenticating several users having access to the same network node. The protocol has been designed, its security analysed and implemented in modified Quantum Key Distribution devices. Two scenarios have been analysed experimentally, the first being both the prover and the verifier honest players, and the second case being the prover a malicious player, the latter demonstrating a notable increase in the quantum bit error rate that prevents a fraudulent authentication.
Zero-knowledge proof system is an important protocol that can be used as a basic block for construction of other more complex cryptographic protocols. Quantum zero-knowledge protocols have been proposed but, since their implementation requires advanced quantum technology devices, experimental implementation of zero-knowledge protocols have not being reported. In this work, we present a quantum zero-knowledge protocol based on a quantum bit commitment protocol that can be implemented with today technology. Hence, our quantum zero-knowledge protocol can be readily implemented.
In a proof of knowledge (PoK), a verifier becomes convinced that a prover possesses privileged information. In combination with zero-knowledge proof systems, PoKs play an important role in security protocols such as in digital signatures and authentication schemes, as they enable a prover to demonstrate possession of certain information (such as a private key or a credential), without revealing it. A PoK is formally defined via the existence of an extractor, which is capable of reconstructing the key information that makes a verifier accept, given oracle access to any accepting prover. We extend this concept to the setting of a single classical verifier and multiple quantum provers and present the first statistical zero-knowledge (ZK) PoK proof system for problems in QMA. To achieve this, we establish the PoK property for the ZK protocol of Broadbent, Mehta, and Zhao (TQC 2024), which applies to the local Hamiltonian problem. More specifically, we construct an extractor which, given oracle access to a provers' strategy that leads to high acceptance probability, is able to reconstruct the ground state of a local Hamiltonian. Our result can be seen as a new form of self-testing, where, in addition to certifying a pre-shared entangled state, the verifier also certifies that provers have access to a quantum system, in particular, a ground state; this indicates a new level of verification for a proof of quantumness.
With the rapid development of quantum computers, proofs of quantumness have recently become an interesting research direction. However, in current schemes for proofs of quantumness, quantum provers face the risk of being maliciously exploited by classical verifiers. Through malicious strategies in interaction with quantum provers, classical verifiers could solve some instances of hard problems that arise from the specific scheme in use. This is due to the lack of formalization that prevents malicious verifiers from extracting useful information in proofs of quantumness. To address this issue, we formalize zero-knowledge proofs of quantumness. Intuitively, the zero-knowledge property necessitates that the information gained by the classical verifier from interactions with the quantum prover should not surpass what can be simulated using a simulated classical prover interacting with the same verifier. As a result, the new zero-knowledge notion can prevent a malicious verifier from exploiting quantum advantage. We find that the classical zero-knowledge proof is sufficient to compile some existing proofs of quantumness schemes into zero-knowledge proofs of quantumness schemes. It appears to be more general to require zero-knowledge proof on the verifier side instead of the prover side. This helps to regulate the verifier's behavior from malicious to be honest-but-curious. As a result, both parties will play not only one role in the proofs of quantumness but also the dual role in the classical zero-knowledge proof. Specifically, Shor's factoring-based scheme and the learning with errors-based scheme in [Brakerski et al., FOCS, 2018] can be transformed into zero-knowledge proofs of quantumness by requiring an extractable non-interactive zero-knowledge argument on the verifier side. Zero-knowledge proofs of quantumness can thus be viewed as an enhanced security notion for proofs of quantumness.