An Efficient V2I Authentication Scheme for VANETs

Table 1

Definition of notations.

Notations	Definition
	Two large prime numbers
	An elliptic curve defined by the equation
G	An additive group with the order q, where G is constitutive of all points on E and the point at infinity O
P	A generator of the group G
	Four security functions, where , , and
	The master secret key of system
	The public key of system
	The secret key of assistant device (some papers also called it a base or a helper)
	The public key of assistant device
	The secret key of RSU
	The public key of RSU
	The time of the time period i
	The identity of OBU
	The partial key in time period i which is generated by TPD offering assistance to key update of secret key of OBU
	The temporary secret key in time period i of OBU
	The temporary public key in time period i of OBU
	The signature of OBU
	The exclusive disjunction operation
	The message concatenation operation