Appreciate the help @unifiedh :)
// This example simulates a situation where an anonymous rider
// wants to find the closest available rider within a given area.
// The application is inspired by the paper https://oride.epfl.ch/
//
// A. Pham, I. Dacosta, G. Endignoux, J. Troncoso-Pastoriza,
// K. Huguenin, and J.-P. Hubaux. ORide: A Privacy-Preserving
// yet Accountable Ride-Hailing Service. In Proceedings of the
// 26th USENIX Security Symposium, Vancouver, BC, Canada, August 2017.
//
// Each area is represented as a rectangular grid where each driver
// anyonymously signs in (i.e. the server only knows the driver is located
// in the area).
//
// First, the rider generates an ephemeral key pair (riderSk, riderPk), which she
// uses to encrypt her coordinates. She then sends the tuple (riderPk, enc(coordinates))
// to the server handling the area she is in.
//
// Once the public key and the encrypted rider coordinates of the rider
// have been received by the server, the rider's public key is transferred
// to all the drivers within the area, with a randomized different index
// for each of them, that indicates in which coefficient each driver must
// encode her coordinates.
//
// Each driver encodes her coordinates in the designated coefficient and
// uses the received public key to encrypt her encoded coordinates.
// She then sends back the encrypted coordinates to the server.
//
// Once the encrypted coordinates of the drivers have been received, the server
// homomorphically computes the squared distance: (x0 - x1)^2 + (y0 - y1)^2 between
// the rider and each of the drivers, and sends back the encrypted result to the rider.
//
// The rider decrypts the result and chooses the closest driver.