Anonymous Veto (AV) and Dining cryptographers (DC) are two basic primitives for the cryptographic problems where the main aim is to hide the identity of the senders of the messages. These can be achieved by classical methods where the security is based either on computational hardness or on shared private keys. In this regard, we present a secure quantum protocol for both DC and AV by exploiting the GHZ correlations. We first solve a generalized version of the DC problem with the help of multiparty GHZ state. This allow us to provide a secure quantum protocol for the AV. Securities for both the protocols rely on some novel and fundamental features of GHZ correlations related to quantum nonlocality.
Anonymous Veto (AV) and Dining cryptographers (DC) are two basic primitives for the cryptographic problems where the main aim is to hide the identity of the senders of the messages. These can be achieved by classical methods where the security is based either on computational hardness or on shared private keys. In this regard, we present a secure quantum protocol for both DC and AV by exploiting the GHZ correlations. We first solve a generalized version of the DC problem with the help of multiparty GHZ state. This allow us to provide a secure quantum protocol for the AV. Securities for both the protocols rely on some novel and fundamental features of GHZ correlations related to quantum nonlocality.
The Anonymous Veto (or dining cryptographers) problem, which allows a voting party in a jury to anonymously veto a decision, which is to be approved unanimously, has a classical solution in form of a protocol, security of which is guaranteed only by computational hardness. We present a generalization to a multi quDit case of Hardy's argument against local realism, which avoids statistical inequalities, and show that generalized Hardy-type correlations allow a simple quantum solution of the problem. This is possible because Hardy-type conditions for correlations precisely determine a specific genuine multipartite entangled state, which can satisfy them.
While many scenarios of anonymous communication can be solved by various famous classical techniques including mix nets or dining cryptographers (DC), an abundant amount of anonymous tasks remains open. In this paper, we present a solution to one such task. Our protocol serves as a private communication channel for quantum messages while ensuring that both the sender and the receiver stay anonymous in a set of all parties. Our protocol is a continuation of our previous work on anonymous transmission of quantum information. The protocol does not require trusted parties, and is secure against an active adversary. It can also withstand denial of service attacks. The protocol exhibits an advantage of quantum resources over classical because no classical solution is known (in the same security settings). Entanglement swapping technique is used to create "symmetry" in the protocol, which makes it very transparent and easier to analyze. The security analysis we present is heavily based on our previous work on quantum anonymous communication. The task we implement is also a nice illustration of a cryptographic task where two parties in a multi-party protocol can be dishonest at the same time, but are not cooperating.
A novel quantum anonymous communication scheme is proposed on the basis of Dining Cryptographers (DC) Problem and nonmaximally entangled qubit pair. The scheme takes advantage of quantum-mechanical impossibility of local unitary transformation between certain nonmaximally entangled states to provide truly random number which can be brightly used in anonymous communication protocols based on DC-Nets. The analysis and discussions demonstrate that the proposed quantum anonymous communication scheme can be performed securely with high capacity and untraceability. The scheme can also be extended to a (2, 2) quantum secret sharing (QSS) scheme.
This paper presents an innovative entanglement-based protocol to address the Dining Cryptographers problem, utilizing maximally entangled |GHZn⟩ tuples as its core. This protocol aims to provide scalability in terms of both the number of cryptographers n and the amount of anonymous information conveyed, represented by the number of qubits m within each quantum register. The protocol supports an arbitrary number of cryptographers n, enabling scalability in both participant count and the volume of anonymous information transmitted. While the original Dining Cryptographers problem focused on a single bit of information—whether a cryptographer paid for dinner—the proposed protocol allows m, the number of qubits in each register, to be any arbitrarily large positive integer. This flexibility allows the transmission of additional information, such as the cost of the dinner or the timing of the arrangement. Another noteworthy aspect of the introduced protocol is its versatility in accommodating both localized and distributed versions of the Dining Cryptographers problem. The localized scenario involves all cryptographers gathering physically at the same location, such as a local restaurant, simultaneously. In contrast, the distributed scenario accommodates cryptographers situated in different places, engaging in a virtual dinner at the same time. Finally, in terms of implementation, the protocol accomplishes uniformity by requiring that all cryptographers utilize identical private quantum circuits. This design establishes a completely modular quantum system where all modules are identical. Furthermore, each private quantum circuit exclusively employs the widely used Hadamard and CNOT quantum gates, facilitating straightforward implementation on contemporary quantum computers.
Anonymity is a fundamental cryptographic primitive that hides the identities of both senders and receivers during message transmission over a network. Classical protocols cannot provide information-theoretic security for such task, and existing quantum approaches typically depend on classical subroutines and multiple private channels, thereby weakening their security in fully adversarial settings. In this work, we introduce the first fully quantum protocol for anonymous communication in realistic quantum networks with a device-independent security proof.
This article introduces the innovative Quantum Dining Information Brokers Problem, presenting a novel entanglement-based quantum protocol to address it. The scenario involves n information brokers, all located in distinct geographical regions, engaging in a metaphorical virtual dinner. The objective is for each broker to share a unique piece of information with all the others simultaneously. Unlike previous approaches, this protocol enables a fully parallel, single-step communication exchange among all the brokers, regardless of their physical locations. A key feature of this protocol is its ability to ensure that both the anonymity and privacy of all the participants are preserved, meaning that no broker can discern the identity of the sender of any received information. At its core, the Quantum Dining Information Brokers Problem serves as a conceptual framework for achieving anonymous, untraceable, and massively parallel information exchange in a distributed system. The proposed protocol introduces three significant advancements. First, while quantum protocols for one-to-many simultaneous information transmission have been developed, this is, to the best of our knowledge, one of the first quantum protocols to facilitate many-to-many simultaneous information exchange. Second, it guarantees complete anonymity and untraceability for all senders, a critical improvement over sequential applications of one-to-many protocols, which fail to ensure such robust anonymity. Third, leveraging quantum entanglement, the protocol operates in a fully distributed manner, accommodating brokers in diverse spatial locations. This approach marks a substantial advancement in secure, scalable, and anonymous communication, with potential applications in distributed environments where privacy and parallelism are paramount.