New Probabilistic Quantum Key Distribution Protocol

Tzonelih Hwang, Chia‐Wei Tsai, Song‐Kong Chong

This work presents a new concept in quantum key distribution called the probabilistic quantum key distribution (PQKD) protocol, which is based on the measurement uncertainty in quantum phenomena. It allows two mutually untrusted communicants to negotiate an unpredictable key that has a randomness guaranteed by the laws of quantum mechanics. In contrast to conventional QKD (e.g., BB84) in which one communicant has to trust the other for key distribution or quantum key agreement (QKA) in which the communicants have to artificially contribute subkeys to a negotiating key, PQKD is a natural and simple method for distributing a secure random key. The communicants in the illustrated PQKD take Einstein-Podolsky-Rosen (EPR) pairs as quantum resources and then use entanglement swapping and Bell-measurements to negotiate an unpredictable key.

Ramona Wolf

Hyung Sup Choi, Ye Jin Han, collin kessinger +1 more

We propose a new quantum key distribution scheme that is based on the optimum expectation values of maximally entangled Greenberger-Horne-Zeilinger states. Our protocol makes use of the degrees of freedom in continuously variable angles, thereby increasing the security of the key distribution. Outlined are two protocols that distribute a key from Alice to Bob using the above idea, followed by an extension that allows for the same key to be shared with Charlie. We show how this scheme provides for certain detection of any eavesdropper through absolute violation rather than the probabilistic violation used in many protocols.

Nanrun Zhou, Lijun Wang, Jie Ding +2 more

Sheila Cobourne

Tzu-Han Lin, Chun‐Wei Yang, Tzonelih Hwang

This study points out that a malicious communicant in Hwang et al.\textquoteright{}s probabilistic quantum key distribution (PQKD) protocol can manipulate the secret key without being detected by using the unitary operation attack. Accordingly, the security requirements of a PQKD protocol, i.e., unpredictability and fairness, cannot be satisfied in their protocol. A possible solution is also provided to solve the problem.