Since the information technology continues to grow and the network applications are getting popular, protecting the privacy of Internet users on the open network becomes a necessary concern. The traditional authentication protocol is not suitable for the requirements of internet security nowadays. That is, it cannot assure that the private information not be revealed during the authentication operation, or be used by malicious terminal service managers for their personal gain in some other business opportunities. Hence, in the dissertation, we propose a deniable authentication protocol based on elliptic curve cryptography (ECC) to satisfy the current public key infrastructure and fulfill the following security requirements of deniable authentication protocols. 1. Each user can prove his/her legitimacy to the designated verifier. 2. The designated verifier cannot prove the identity of the user to the third party even though the verifier provides the testimonials. Moreover, the proposed deniable authentication protocol is suitable for the mobile devices since it only needs limited computation resources.