  When dealing with privatized data, it is important to be able to protect
against malformed user inputs. This becomes difficult in MPC systems as each
server should not contain enough information to know what values any user has
submitted. In this paper, we implement an MPC technique to verify blinded user
inputs are unit vectors. In addition, we introduce a BGW circuit which can
securely aggregate the blinded inputs while only releasing the result when it
is above a public threshold. These distributed techniques take as input a unit
vector. While this initially seems limiting compared to real number input, it
is quite powerful for cases such as selecting from a list of options,
indicating a location from a set of possibilities, or any system which uses
one-hot encoding.
