Quantum hashing via single-photon states

A quantum hashing is a promising generalization of the cryptographic hashing concept on the quantum domain. In this case, the hash function encodes a classical input state into a quantum state so that to optimize the trade-off between one-way property and collision resistance. In the present work, we develop a quantum hashing technique wherein a quantum hash is constructed as a sequence of single-photon qubits [1] or qudits [2]. A proof-of-principle implementation of the quantum hashing protocol using orbital-angular momentum encoding of single photons demonstrates good agreement with theoretical predictions. In particular, it shows that the number of qudits decreases with increase of their dimension for an optimal ratio between collision probability and decoding probability of the hash [2]. The prospects of increasing dimension of information carriers, which makes quantum hashing with single photons more efficient, are discussed [3].
[1] D. A. Turaykhanov, D. O. Akat'ev, A. V. Vasiliev, F. M. Ablayev, and A. A. Kalachev. Quantum hashing via single-photon states with orbital angular momentum. Physical Review A, 104, 052606 (2021)
[2] D.O. Akat’ev, A.V. Vasiliev, N.M. Shafeev, F.M. Ablayev, A.A. Kalachev. Multiqudit quantum hashing and its implementation based on orbital angular momentum encoding. Laser Physics Letters 19, 125205 (2022)
[3] D. A. Turaykhanov, N.M. Shafeev, A. V. Vasiliev, F. M. Ablayev, and A. A. Kalachev. Quantum hashing with orbital angular momentum and polarization encoding. (to be submitted)