A method of encrypting a passcode is disclosed. In one embodiment, the method includes: receiving an indication of a portion of the passcode; calculating a plaintext value based at least in part on the indication, wherein the plaintext value represents an encoded portion of the passcode; encrypting the plaintext value into ciphertext using a homomorphic encryption system; and 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.