HCV: Practical Multi-Keyword Conjunctive Query with Little Result Pattern Leakage

Algorithm 4

HCV conjunctive searchable encryption scheme.

(1)	—Setup
	Input: Security Parameter k, Inverted Index
	Output: K, EDB
(2)	Generate key according to ;
(3)	Get the EMM as in ;
(4)	Compute CV database using Algorithm 1;
(5)	Encrypt CV as equation (15) to acquire ECV;
(6)	set ,
(7)	return .
(8)	—Token
(9)	The same as CVX.
(10)	—Query;
	Input: tk, EDB
	Output: result
(11)	initialize a tag vector S;
(12)	initialize a bool vector ;
(13)	initialize a integer vector ;
(14)	(a) Server parse , and parse ;
(15)	fordo
(16)	if ;
(17)	return;
(18)	Server send Query Request command to Client.
(19)	(b) fordo
(20)	set a vector and encrypt it to as equation (16), send and to Server.
(21)	(c) Server do as follows:
(22)	set each element of to integer 1 fordo
(23)	set ,
(24)	fordo
(25)	if then
(26)	;
(27)	else
(28)	;
(29)	Finally, the Server computes ;
(30)	return