Conference Key Agreement Sample Contracts
SAMOP 2021 – QI FridayConference Key Agreement • August 30th, 2021
Entanglement plays a crucial role in the security of quantum key dis- tribution. A secret key can only be obtained by two parties if there exists a corresponding entanglement-based description of the protocol in which entanglement is witnessed, as shown by Curty et al (2004). Here we investigate the role of entanglement for the generalization of quantum key distribution to the multipartite scenario, namely con- ference key agreement. In particular, we ask whether the strongest form of multipartite entanglement, namely genuine multipartite en- tanglement, is necessary to establish a conference key. We show that, surprisingly, a non-zero conference key can be obtained even if the par- ties share biseparable states in each round of the protocol. Moreover we relate conference key agreement with entanglement witnesses and show that a non-zero conference key can be interpreted as a non-linear entanglement witness that detects a class of states which cannot be detected by usual linear entangl
Efficient Quantum Conference Key Agreement over Quantum NetworksConference Key Agreement • May 19th, 2025
Abstract— Quantum conference key agreement (CKA) is useful for many applications that involve secure communication or collaboration among multiple parties. While CKA over quantum networks can be achieved using pairwise quantum key distribu- tion, a more efficient approach is to establish keys among the parties directly through multipartite entanglement distribution. Existing studies on multipartite entanglement distribution, how- ever, are not designed for CKA, and hence do not aim to optimize key rate. In this paper, we first develop an efficient 3-party CKA strategy based on a closed-form expression that we derive for estimating errors. We then develop a general strategy for N - party CKA that accounts for estimated key rates on individual network paths. For both cases, we use multipath routing to improve key rate. We evaluate our approach in a wide range of settings and demonstrate that it achieves high key rate and degrades gracefully when increasing the number of parties.
Quantum Conference Key Agreement with Photon LossConference Key Agreement • October 1st, 2020
Conference key agreement (CKA) is an information processing task where more than two parties want to share a common secret key. Here, we present a loss-resilient protocol for CKA, based on redundant encoding and error correction. Our protocol provides a speed-up in transmission rate over the existing lossy CKA protocol. However, encoding and error correction come with extra cost. We show that, using photon sources with creation probability p “ 0.3, our protocol’s secret key rate can overcome the existing protocol’s. Hence, high probability entangled photon sources are required for realistic implementation of our loss-resilient protocol.
Fully device independent Conference Key AgreementConference Key Agreement • November 21st, 2020
Quantum communication allows cryptographic security that is provably impossible to obtain using any classical means. Probably the most famous example of a quantum advantage is quantum key distribution (QKD) [1, 2], which allows two parties Alice and Bob to exchange an encryption key whose security is guaranteed even if the adversary has an arbitrarily powerful quantum computer. What’s more, properties of entanglement lead to the remarkable feature that security is sometimes possible even if the quantum devices used to execute the protocol are largely untrusted. Specifically, the notion of device independent (DI) security [3, 4] models quantum devices as black boxes in which we may only choose measurement settings and observe measurement outcomes. Yet, the quantum state and measurements employed by such boxes are unknown, and may even be prepared arbitrarily by the adversary.
Intrinsic Non-Locality and Device-Independent Conference Key AgreementConference Key Agreement • February 25th, 2022
These definitions can easily be modified to the case in which the eavesdropper is restricted by quantum mechanics. The main modification is that the underlying correlation is a quantum correlation and the eavesdropper is allowed a quantum extension of it. We denote the resulting capacity by DIQ(p).
Quantum Conference Key Agreement: A ReviewConference Key Agreement • October 6th, 2020
Conference key agreement (CKA), or multipartite key distribution, is a cryptographic task where more than two parties wish to establish a common secret key. A composition of bipartite quantum key distribution protocols can accomplish this task. However, the existence of multipartite quantum correlations allows for new and potentially more efficient protocols, to be applied in future quantum networks. Here, we review the existing quantum CKA protocols based on multipartite entanglement, both in the device-dependent and the device-independent scenario.