A Lightweight Three-Factor Authentication and Key Agreement Scheme for Multigateway WSNs in IoT

Table 2

Notations of BAN logic.

Notations	Descriptions
	P believes X is true
	P sees X and is capable of reading and repeating it
	P once said X; at some time, P has sent the message containing X
	P has control or jurisdiction over X
	X is fresh which means it was never sent before the current execution of the protocol
	Both P and Q can use the shared key K to communicate with each other, and K is an intact key
	X is a secret only known to P and Q and possibly to principals trusted by them
	X combined with Y