Anonymizing communication becomes a substantial issue to enhance security and facing attacks. Huge researches are made in this field aiming to ensure a secure and anonymous communication. In vehicular ad hoc networks (VANets), this concept is used in different application areas like military domains, in which hiding destinations identities is necessary to avoid consequences attacks. In this paper, we propose a model of security to ensure anonymity in vehicular ad-hoc network. We inspire this model from the Invisible Internet project (I2P) in which we continue our previous work by adapting some of I2P mechanisms and algorithms in VANets. We adapt the I2P protocol to respond to several requirements of VANets. The proposed model is based on tunnels and encryption algorithms that use digital signatures and authentication mechanisms. We aim to make the proposed protocol more secure by ensuring anonymity, integrity, non- repudiation and confidentiality. We prove the effectiveness and the security of our proposed model by analysing different cases of anonymity and showing performance results. We have launched our simulations using NS3 platform.