International Association
for Cryptologic Research

Recently, the problem of quantum position-verification has been extensively analyzed in the formal notion but all existing ceremonial single-round position-verification schemes are insecure. We propose here a different notion for position-verification where distant verifiers determine the actions of the prover through quantum non-local correlations generated by local measurements at the provers’ site: instead of sending challenge encoded over flying qubits, one of the verifiers teleports the challenge to the prover while prover is required to perform single qubit measurements as well as Bell state measurements and return the outcomes. It allows controlling the prover’s actions and bound him/her to receive challenge from one of the verifiers, measure in known basis, teleport to another verifier, and return the measurement outcomes to all verifiers simultaneously. Here, no-signaling principle assures that any group of dishonest provers, not at the position to be verified, cannot simulate their actions with the prover who is supposed to be at the specified position. The scheme enables verifiers to trace the origin of received information and hence identify dishonest provers with very high probability, greater than 1-1/2*n, where n is the number of entangled pairs used.