Attacks and Solutions for a Two-Factor Authentication Protocol for Wireless Body Area Networks

Table 1

Notations table.

Symbol	Description
	-th user, his/her identity, his/her password
	-th gateway, its identity, its secret key
	-th sensor, its identity
	Network identifier of the sensor set
	Shared key between sensor and gateway
	Session key generated by user
	Session key generated by gateway
	Session key generated by user
	-th message
	Temporary pseudoidentity of and
	Temporary random number
,	Biometric extraction function, decryption function
	Biometric information of the -th user
()	Hash function
	Bitwise XOR operation
	Concatenate operation