title: Multipartite entanglement verification resistant against dishonest parties.
abstract: Future quantum information networks will consist of quantum and classical agents, who have the ability to communicate in a variety of ways with trusted and untrusted parties and securely delegate computational tasks to untrusted large-scale quantum computing servers. Multipartite quantum entanglement is a fundamental resource for such a network and, hence, it is imperative to study the possibility of verifying a multipartite entanglement source in a way that is efficient and provides strong guarantees even in the presence of multiple dishonest parties. In this Letter, we show how an agent of a quantum network can perform a distributed verification of a source creating multipartite Greenberger-Horne-Zeilinger (GHZ) states with minimal resources, which is, nevertheless, resistant against any number of dishonest parties. Moreover, we provide a tight tradeoff between the level of security and the distance between the state produced by the source and the ideal GHZ state. Last, by adding the resource of a trusted common random source, we can further provide security guarantees for all honest parties in the quantum network simultaneously.
authors.affiliation: LTCI, CNRS-Télécom ParisTech, Paris 75013, France.
authors.forename: Anna
authors.initials: A
authors.lastname: Pappa
authors.forename: André
authors.initials: A
authors.lastname: Chailloux
authors.forename: Stephanie
authors.initials: S
authors.lastname: Wehner
authors.forename: Eleni
authors.initials: E
authors.lastname: Diamanti
authors.forename: Iordanis
authors.initials: I
authors.lastname: Kerenidis