Secure and Efficient Communication in VANETs Using Level-Based Access Control

Algorithm 3

Algorithm for indistinguishability experiment under CCA attack .

	Input: a security parameter and a random bit
	Output: the success of the attack.
	Setup parameters: the setup process is same with Algorithm 2.
	Phase I: learning
	Prechallenge: the prechallenge process is same with Algorithm 2.
(1)	Phase II: challenging
	if
	and
	and
	have never been executed, then
	If , then return 1
	else return 0
	else
	return
	end