Science & Engineering Research Support soCiety (SERSC)
A Vehicular Ad hoc NETwork (VANET) uses cars as mobile nodes in a MANET to create a mobile network. In the vehicular ad hoc networks the security is an important concern. For security, VANETs adopt the Public Key Infrastructure (PKI) and Certificate Revocation Lists (CRLs). In the public key infrastructure system, the authentication of a received message is performed by checking if the certificate of the sender is included in the current CRLs and verifying the authenticity of the certificate and signature of the sender. But it takes more time for CRL checking process. So, in order to overcome this problem the authors use an efficient revocation check process in EMAP uses a keyed Hash Message Authentication Code (HMAC), where the key used in calculating the HMAC is shared only between non-revoked On-Board Units (OBUs).