This paper proposes an identification and key exchange scheme in secure VANETs based on group signature. Security requirements such as authentication, conditional privacy, non-repudiation, and confidentiality are required to satisfy various vehicular applications. Although the existing group signature schemes are suitable for secure vehicular communications, they do not provide mutual identification and key exchange for data confidentiality. The principal idea of this paper is that the proposed scheme allows only one credential to authenticate ephemeral Diffie-Hellman parameters generated be all the session keys. Our scheme achieves security requirements for various VANET-based applications.