Quantum secret sharing using GHZ state qubit positioning and selective qubits strategy for secret reconstruction
This work addresses secure secret sharing in quantum cryptography, presenting an incremental improvement over existing protocols.
The paper tackles the problem of quantum secret sharing by introducing a protocol that uses GHZ product states and selective qubits for reconstruction, achieving a (3,3) scheme that can be extended to (n,n) with security against malicious attacks.
The work presents a novel quantum secret sharing strategy based on GHZ product state sharing between three parties. The dealer, based on the classical information to be shared, toggles his qubit and shares the product state. The other parties make their Bell measurements and collude to reconstruct the secret. Unlike the other protocols, this protocol does not involve the entire initial state reconstruction, rather uses selective qubits to discard the redundant qubits at the time of reconstruction to decrypt the secret. The protocol also allows for security against malicious attacks by an adversary without affecting the integrity of the secret. The security of the protocol lies in the fact that each party's correct announcement of their measurement is required for reconstruction, failing which the reconstruction process is jeopardized, thereby ascertaining the $(3,3)$ scheme which can further be extended for a $(n,n)$ scheme.