A Collusion-Resistant Identity-Based Proxy Reencryption Scheme with Ciphertext Evolution for Secure Cloud Sharing

Table 2

Comparison of the representative scheme and the proposed scheme based on essential characteristics.

Characteristics	Update				Delegation
	SHB	LLWS	GA1	Proposed	SHB	GA1	GA2	Proposed
Interactive	Yes	No	No	No	No	No	No	No
Multiuse	TM	EM	EM	TM	No	EM	No	No
Transitive	Yes	No	No	Yes	No	No	No	No
Transferable	—	—	—	—	No	Yes	Yes	No
Collusion safe	No	Yes	No	Yes	Yes	No	No	Yes
Ciphertext optimal	Yes	No	No	Yes	Yes	No	Yes	Yes
Achieved security	CPA	CPA	CPA	CPA	CPA	CPA	CPA	CPA
Standard model	Yes	Yes	No	No	Yes	No	No	No
Identity-based	No	Yes	Yes	Yes	No	Yes	Yes	Yes