Improved Secure and Lightweight Authentication Scheme for Next-Generation IoT Infrastructure

Table 1

Notations used in the proposed scheme.

Notations	Descriptions
	legal user
	user identity
	Legal server
	user password
	Private key and number of server
	Arbitrary number for
	User’s smart card
	Time stamp obtained at user’s side
	Server’s current time stamp
	Threshold value
	Time of transmission delay
	XOR operator
	Concatenation operator
	Noncollision hash function
	Session key
	The attacker
	Biometric of
	Long-term key
	Private communication channel
	Public communication channel