User Authentication using Visual Cryptography

User authentication is an important process in the area of security. Most of the existing user authentication schemes uses computationally expensive cryptographic algorithms. Also, these protocols cannot successfully prevent brute force and dictionary attacks. Visual cryptography is a secret sharing technique which requires less computation. Here, decryption process depends on the property of human vision. Even though visual cryptography offers a computationally inexpensive way of performing encryption and decryption, only few user authentication schemes were proposed using this technique. None of them are suitable for general purpose applications as they possess various vulnerabilities. There are few challenges in designing a user authentication scheme using visual cryptography because of its property that security is lost if we use the same key more than once. In this paper, we suggest a new protocol for authenticating user to server, using an encryption technique based on visual cryptography.