Protecting Location Privacy for Outsourced Spatial Data in Cloud Storage

Algorithm 1

Index modification algorithm for SHC.

Input: POIs’ indexes 𝐼^′, max gap 𝑀

Output: A modified POIs’ indexes 𝐼^∗

(1)  𝑏 = first index in 𝐼^′;

(2)  for  each index 𝑖∈ 𝐼^′  do

(3)   if  𝑖−𝑏>𝑀  then

(4)     𝑖=𝑏+𝑀;

(5)     𝐼^∗=𝐼^∗  ∪  (𝑖, encrypted POI);

(6)     𝑏=𝑖;

(7)  else

(8)     𝑏=𝑖;

(9)   end  if

(10) end  for

(11)  return  𝐼^∗