In the highly growing digital world, information sharing is important common. But it must be secured else adversary can either intercept or delete partially/fully information. Hence, it will be useless to specific human but it may be helpful to adversary. In today's road market, vehicles are most useful to assist persons through broadcasting vehicles regarding information such that current position, traffic, environment, etc. to other vehicles in a secure vehicular communication. We will use public-private key mechanism to achieve this scenario in a public domain. The main goal of this paper is to improve security of exchanging message in terms of confidentiality, authentication, access & availability. Hence, we have suggested an approach to fulfill these security needs for information transmission between two or more vehicles in doubtful network infrastructure. Thus, vehicles can send/receive their important credentials through our secure message exchanging algorithm. Because, in our algorithm, we have used idea of public-private key encryption-decryption mechanism in the computation of messages which is sent over public channel.