Anonymous Conference Key Agreement using GHZ states
This example protocol achieves the functionality of quantum conference key agreement anonymously. This protocol allows multiple parties in a quantum network to establish a shared secret key anonymously.
- First, the sender notifies each receiver in the network anonymously
- The entanglement source generates and distributes sufficient GHZ states to all nodes in the network
- The GHZ states are distilled to establish multipartite entanglement shared only by the participating parties (the sender and receivers)
- Each GHZ state is randomly chosen to be used for either Verification or Key Generation. For Key Generation rounds, a single bit of the key is established using one GHZ state by measuring in the Z-basis
- If the sender is content with the Verification results, they can anonymously validate the protocol and conclude that the key has been established successfully.
Protocol 1: Anonymous Verifiable Conference Key Agreement
Input: Parameters and
Requirements: A source of n-party GHZ states; private randomness sources; a randomness source that is not associated with any party; a classical broadcasting channel; pairwise private communication channels
Goal: Anonymoous generation of key between sender and receivers
- The sender notifies the receivers by running the Notification protocol
- The source generates and shares GHZ states
- The parties run the Anonymous Multipartite Entanglement protocol on the GHZ states
- For each -partite GHZ state, the parties do the following:
- They ask a source of randomness to broadcast a bit such that Pr
- Verification round: If b = 0, the sender runs Verification as verifier on the state corresponding to that round, while only considering the announcements of the receivers. The remaining parties announce random values.
- KeyGen round: If b = 1, the sender and receivers measure in the Z-basis.
- If the sender is content with the checks of the Verification protocol, they can anonymously validate the protocol