Tree-Based Public Key Encryption with Conjunctive Keyword Search

Table 3

Comparison with previous PECK schemes on time and space complexity.

Scheme	T1	T2	T3	S1	S2
SPE-CKS [8]
SPE-SMKS [9]
SA-SCF-PECKS [10]
PMSEHS [13]
T-PECK
Denotation	and are two cyclic groups of a large prime order, and is a bilinear map [35]
	and : the time cost of one exponentiation computation in , and , respectively
	: the time cost of one pairing operation
	, and : the size of an element of , and , respectively
	T1, T2, and T3 represent the time complexity of index building, trapdoor generation, and search, respectively
	S1 and S2 represent the space complexity of index and trapdoor, respectively