Authentication is one of the most important requirements which all information security objectives and authentication mechanism is very essential component in many applications. Before 1970s, authentication is considered to be a part of secrecy. With the invention of public key cryptography, in particular digital signatures, authentication become a separate security objective. In general, authentication can be divided into two categories: data authentication and entity authentication. Data authentication provides assurance of the origin of documents while entity authentication validates the identity of the entities. Digital signatures are essential primitives offering data authentication. Expending on application requirements, there are various types of digital signatures such as blind signatures, forward secure signatures, proxy signatures, etc. On the other hand, in order to verify an identity of a user, entity authentication relies on authentication targets. Such targets an be a password (the things the user knows), security token (the things the user has), or biometric identifier (the things the user is).
This thesis studies authentication techniques including data and entity authentication. In a study on data authentication, we focus on the forward secure signatures, a type of digital signatures coping with the key exposure problem. Traditional forward secure signatures require to define the life time of the schemes as an input parameter. Consequently, not only the operation period of the schemes is limited but also the complexity and performance of the schemes depend completely on this parameter. The larger the value of the life time is, the lower the performance f the schemes. We have proposed yet another forward secure signature based on bilinear pairings to overcome this drawback of traditional forward secure signature scheme. Our construction is the first one which requires the general security parameters only independent to the life time of the scheme. As a result, our forward secure signature scheme's performance is superior to the existing constructions. That is the proposed scheme achieves the $\It{unlimited}$ life time while keeping the operation complexity as well as sizes of keys and signatures constant. We also have shown that our signature scheme is provably secure under the assumption of Computational Diffie-Hellman problem. Moreover, since our construction based on bilinear pairings on elliptic curves, signature sizes and key sizes are short but security is still guaranteed.
On the other hand, we investigate the entity authentication, specifically, the remote authentication using smart cards and password constructed from bilinear pairings. Remote authentication is an important mechanism to control user access to remote systems in a way such that only legitimate users can be authenticated before being granted services. There are several methods to implement authentication but for human, password authentication is preferred. At present, due to beneficial properties, bilinear pairings and elliptic curves are utilized intensively to design cryptographic schemes in general and authentication scheme in particular. However, incautious design may result in insecure constructions. We examine several remote authentication schemes built from bilinear pairing on elliptic curves and explore their security weaknesses. We also suggest a new mutual authentication scheme which not only overcomes security weakness of the previous schemes but also is more efficient from the point of computational complexity. Furthermore, our proposed scheme allows two entities agree on a session key after mutual authentication process finishes. Besides, we prove the security of the proposed scheme in a way that there exists no polynomial time adversary can break our scheme under the assumption of the Gap Diffie-Hellman problem.
