  Secure communication is one of the key applications of quantum networks. In
recent years, following the demands for identity protection in classical
communication protocols, the need for anonymity has also emerged for quantum
networks. Here, we demonstrate that quantum physics allows parties - besides
communicating securely over a network - to also keep their identities secret.
We implement such an anonymous quantum conference key agreement by sharing
multipartite entangled states in a quantum network. We demonstrate the protocol
with four parties and establish keys in subsets of the network - different
combinations of two and three parties - whilst keeping the participating
parties anonymous. We additionally show that the protocol is verifiable and run
multiple key generation and verification routines. Our work thus addresses one
of the key challenges of networked communication: keeping the identities of the
communicating parties private.
