Secure and Practical Group Nearest Neighbor Query for Location-Based Services in Cloud Computing

Table 2

Key notations.

Notations	Description
	a d-bit string
	The number of users in the group
	The set of point-of-interests
	The encrypted
	The size of database
	The coordinate of a point in
	The coordinate of an LBS user
	The set of coordinates for LBS users
	Invertible matrices
	Random numbers