Vehicular Ad Hoc Network is mainly used in safety applications to avoid road accidents by disseminating the alert messages or dangerous information among the drivers securely. This alert messages or dangerous information must be highly secured from the access of intruders or attackers. Misbehaviour or malicious node detection is a major problem in VANET if any vehicles disseminate the messages maliciously. Checking the variation in the behaviour of vehicular nodes, detection of misbehaviour and the malicious vehicular nodes continuously makes a highly secured VANET. In this paper, message dissemination using optimal blowfish algorithm based signcryption technique in vehicular networks is proposed to secure the data from the third party person or attackers.