A method for encrypting a passcode is disclosed. In one embodiment, the method includes: receiving an indication of a portion of the passcode from a user; encoding the portion of the passcode; encrypting the encoded portion into ciphertext using a homomorphic encryption system; updating a cumulative encryption string by executing a cumulative operation to aggregate the ciphertext corresponding to the encoded portion into the cumulative encryption string computed for a previous portion of the passcode, wherein the cumulative operation is dictated by a homomorphic property of the homomorphic encryption system; and generating a passcode message based at least in part on the cumulative encryption string, wherein the passcode message includes a message authentication code.