Title: Entanglement verification protocols for distributed systems based on the Quantum Recursive Network Architecture,
Abstract: In distributed systems based on the Quantum Recursive Network Architecture,
quantum channels and quantum memories are used to establish entangled quantum
states between node pairs. Such systems are robust against attackers that
interact with the quantum channels. Conversely, weaknesses emerge when an
attacker takes full control of a node and alters the configuration of the local
quantum memory, either to make a denial-of-service attack or to reprogram the
node. In such a scenario, entanglement verification over quantum memories is a
means for detecting the intruder. Usually, entanglement verification approaches
focus either on untrusted sources of entangled qubits (photons, in most cases)
or on eavesdroppers that interfere with the quantum channel while entangled
qubits are transmitted. Instead, in this work we assume that the source of
entanglement is trusted, but parties may be dishonest. Looking for efficient
entanglement verification protocols that only require classical channels and
local quantum operations to work, we thoroughly analyze the one proposed by
Nagy and Akl, that we denote as NA2010 for simplicity, and we define and
analyze two entanglement verification protocols based on teleportation (denoted
as AC1 and AC2), characterized by increasing efficiency in terms of intrusion
detection probability versus sacrificed quantum resources.