Table 4.

Comparison of functionality features.

	Protocol
Functionality	[3]	[6]	[8]	[10]	[12]	[18]	Ours
Provides password change facility	No	Yes	Yes	Yes	Yes	Yes	Yes
Provides mutual authentication	No	No	Partial Yes	Partial Yes	Yes	Yes	Yes
Provides three-factor security	No	No	No	Partial Yes	Yes	Yes	Yes
Resists node capture attack	No	No	No	No	Yes	No	Yes
Resists denial-of-service attack	No	No	No	No	Yes	No	Yes
Provides user anonymity	No	Yes	No	Yes	Yes	Yes	Yes
Provides key agreement	No	No	No	No	Yes	Yes	Yes
Provides formal security analysis	No	No	Yes	Yes	Yes	Yes	Yes
Provides access of real-time-data to U from SN	No	No	No	No	Yes	Yes	Yes