Fully Constant-Size CP-ABE with Privacy-Preserving Outsourced Decryption for Lightweight Devices in Cloud-Assisted IoT

Table 1

Properties comparison.

Scheme	Access structure	Constant-size ciphertext	Constant-size private key	Outsourced decryption	Security	Bilinear group
[23]	Strict AND-gate Policy				Selectively IND-CPA secure	Prime order
[20]	Threshold				Selectively IND-CPA secure	Prime order
[21]	Threshold				Selectively IND-CPA secure	Prime order
[16]	Access tree				Selectively IND-CPA secure	Prime order
[17]	Linear secret sharing schemes (LSSS) [40]				Selectively IND-CPA-secure	Prime order
[18]	LSSS				Selectively IND-CPA secure	Prime order
[41]	LSSS				Fully (adaptively) IND-CPA secure	Composite order
[26]	AND-gate policy with wildcards				Selectively IND-CPA secure	Prime order
[27]	AND-gate policy with wildcards				Fully (adaptively) IND-CPA secure	Composite order
[19]	Tolerant AND-gate Policy based on bits string				Selectively IND-CCA secure	Prime order
[31]	LSSS			(not privacy-preserving)	Selectively IND-CPA secure	Prime order
[34]	LSSS			(not privacy-preserving)	Selectively IND-CPA secure	Prime order
[33]	LSSS			(not privacy-preserving)	Selectively IND-CPA secure	Prime order
[29]	Tolerant AND-gate policy based on bits string				Selectively IND-CPA secure	Prime order
[25]	Strict AND-gate policy				Selectively IND-CPA secure	Prime order
[22]	Threshold				Selectively IND-CCA2 secure	Prime order
[24]	Strict AND-gate policy				Selectively IND-CPA secure	Prime order
[28]	AND-gate policy with wildcards				Selectively IND-CPA secure	Prime order
Ours	Tolerant AND-gate policy based on bits string			(privacy-preserving)	Selectively IND-CCA secure	Prime order