Monchi is a new protocol aimed at privacy-preserving biometric identification. It begins with scores computation in the encrypted domain thanks to homomorphic encryption and ends with comparisons of these scores to a given threshold with function secret sharing. We here study the integration in that context of scores computation techniques recently introduced by Bassit et al. that eliminate homomorphic multiplications by replacing them by lookup tables. First, we extend this lookup tables biometric recognition solution by adding the use of function secret sharing for the final comparison of scores. Then, we introduce a two-party computation of the scores with lookup tables which fits nicely together with the function secret sharing scores comparison. Our solutions accommodate well with the flight boarding use case introduced by Monchi.
