Quantum networks enable secure communication, distributed computing, and precision sensing beyond classical capabilities. Recent advances have progressed from two-node links to multi-node architectures, enabling rigorous tests of multiparty quantum communication protocols. Among these, quantum secret sharing (QSS) leverages multipartite entanglement to distribute secrets such that only authorized parties can reconstruct them. Here, we present a three-node quantum communication testbed with a triangular topology, each edge implemented by a 1.3-meter-long transmission line, and use this testbed to demonstrate QSS. We demonstrate state transfer and entanglement generation between all node pairs, create genuine tripartite GHZ entanglement, and implement QSS of classical information. Our experiments show that the QSS protocol detects eavesdropping in situ, ensuring secure secret distribution on a superconducting platform.
Superconducting microwave quantum networks is a rapidly developing field, enabling distributed quantum computing and holding a promise for hybrid architectures in quantum internet. Quantum secret sharing (QSS) is one of the key protocols for multipartite quantum networks and can provide an unconditionally secure way to share quantum states among
n players. Using microwave two-mode squeezed states as an entanglement resource, we experimentally implement a QSS protocol with
n=3, where a subset of at least
k=2 players must collaborate to faithfully reconstruct the original secret state. We demonstrate reconstructed-state fidelities that surpass the asymptotic no-cloning threshold of
Fnc=2/3 and identify a parameter regime that allows for unconditionally secure communication in the presence of an omnipotent dishonest player. Furthermore, we experimentally explore inherent connections between QSS and other important quantum information processing tasks, such as quantum dense coding and elementary quantum error correction of channel erasures. Finally, we discuss extensions of QSS and its relation to the concept of blind quantum computing.
Quantum secret sharing (QSS) is a cryptographic protocol that leverages quantum mechanics to distribute a secret among multiple parties. With respect to the classical counterpart, in QSS, the secret is encoded into quantum states and shared by a dealer such that only an authorized subsets of participants, i.e., the players, can reconstruct it. Several state-of-the-art studies aim to transpose classical secret sharing into the quantum realm, while maintaining their reliance on traditional network topologies (e.g., star, ring, and fully connected), and require that all the
nplayers calculate the secret. These studies exploit the Greenberger–Horne–Zeilinger state, which is a type of maximally entangled quantum state involving three or more qubits. However, none of these works account for redundancy, enhanced security/privacy features, or authentication mechanisms able to fingerprint players. To address these gaps, in this article, we introduce a new concept of QSS, which leans on a generic distributed quantum network, based on a threshold scheme, where all the players collaborate also to the routing of quantum information among them. The dealer, by exploiting a custom flexible weighting system, takes advantage of a newly defined quantum Dijkstra algorithm to select the most suitable subset of
tplayers, out of the entire set on
nplayers, to involve in the computation. To fingerprint and authenticate users, CRYSTAL-Kyber primitives are adopted, while also protecting each player’s privacy by hiding their identities. We show the effectiveness and performance of the proposed protocol by testing it against the main classical and quantum attacks, thereby improving the state-of-the-art security measures.
Classical secret sharing proposed by Shamir used classical computational power in classical cryptography to achieve secret key sharing, but with the advent of quantum systems, computational power can be overruled. To ensure a secure secret sharing scheme independent of computational power, a scheme independent of computational complexity is needed to achieve security. This paper will provide a protocol dependent on inherent secure nature of quantum cryptography (quantum no cloning theorem and quantum measurement rule). A secure multiparty quantum secret sharing scheme has been proposed to ensure that no one can eavesdrop or extract any share of the secret message via inherent security provided by quantum entanglement swapping and quantum teleportation. Entanglement swapping is a process that allows two non-interacting quantum systems to be entangled. Whereas, Quantum teleportation allows a party to send a qubit to another entangled party without sending the qubit over the channel. Moreover, in order to ensure security against possible active attacks, sender himself will generate and distribute EPR pairs to be used in the scheme. Result will be a secure multiparty QSS scheme which will be secure against internal and external eavesdropping, masquerading and brute-force attacks.
As an important branch of quantum secure multi-party computation, quantum secret sharing (QSS) can distribute secret information among dishonest network nodes without revealing the secrets. In this study, a new four-party QSS protocol based on locally indistinguishable orthogonal product (LIOP) states is first proposed for quantum network communication. Then, the general multiparty QSS model based on LIOP states will be expanded. Combined with the property of LIOP states and obfuscating operation, the source node can send the secrets to different destination nodes in the quantum network. Accordingly, it is proven that the destination nodes have to work together to recover the shared secrets against some existing attacks. Furthermore, no entangled resources and complicated operations are required in the presented protocol. We hope the results could make positive effects to the development of quantum secure communication in the future.
Secret sharing is a conventional technique for realizing secure communications in information networks, where a dealer distributes to n players a secret, which can only be decoded through the cooperation of k (n/2<k≤n) players. In recent years, quantum resources have been employed to enhance security of secret sharing, which has been named quantum secret sharing (QSS). A multipartite bound entanglement (BE) state of an optical field, due to its special entanglement features, can be used in quantum networks to improve security and flexibility of communication. We design and experimentally demonstrate a QSS protocol, where the dealer modulates a secret on a four-partite BE state and then distributes the submodes of the BE state to four spatially separated players. The presented QSS scheme has the capability to protect secrets from eavesdropping and dishonest players, because a nonlocal and deterministic BE state is shared among four authorized players.
Quantum secret sharing (QSS) is an essential primitive for the future quantum internet, which promises secure multiparty communication. However, developing a large-scale QSS network is a huge challenge due to the channel loss and the requirement of multiphoton interference or high-fidelity multipartite entanglement distribution. Here, we propose a three-user QSS protocol without monitoring signal disturbance, which is capable of ensuring the unconditional security. The final key rate of our protocol can be demonstrated to break the Pirandola-Laurenza-Ottaviani-Banchi bound of quantum channel and its simulated transmission distance can approach over 600 km using current techniques. Our results pave the way to realizing high-rate and large-scale QSS networks.