International Association for Cryptologic Research

Ph.D. Database

The aim of the IACR Ph.D. database is twofold. On the first hand, we want to offer an overview of Ph.D. already completed in the domain of cryptology. Where possible, this should also include a subject classification, an abstract, and access to the full text. On the second hand, it deals with Ph.D. subjects currently under investigation. This way, we provide a timely map of contemporary research in cryptology. All entries or changes need to be approved by an editor. You can contact them via phds (at)


Jayaprakash Kar (#283)
Name Jayaprakash Kar
Institution Utkal University
Topic of his/her doctorate. Algorithms for Cryptographic Protocols Using Elliptic Curve Cryptography
Category cryptographic protocols

The transaction over Internet has become quite common in all business scenarios. These transactions need all security requirements such as authentication, confidentiality etc. Further the use of hand held devices like smart card, PDA etc are becoming more common. These devices have limitations with respect to memory, computational power and energy. Hence the security protocols used to support business transaction need to be computationally eĀ±cient. Mostly the security of the existing protocols are based on two mathematical hard problems namely Integer factorization (IF) and Discrete Logarithm Problem (DLP). The key length of such protocols is of order 512 or 1024 bits. In addition from the cryptanalysis point of view they are sub-exponential in nature. In contrast Elliptic Curve Cryptosystem (ECC), whose security is based on Elliptic Curve Discrete Logarithm Problem (ECDLP) is fully exponential and provide more security per bit.

In this thesis we have developed protocols for key exchange, e-cash system and deniable authentication. In key exchange protocol, two entities wish to agree on keying information i.e the parameter needs to generate a session key secretly over a distributed network. The three diferent proposed protocols for key exchange are password based where the secret key are not uniformly distributed over a large space, but rather chosen from a small set of possible values. Another proposed key exchange is of two-party identity based. A two-party key exchange (or agreement) protocol is used to establish a common session key for two specified entities, in which both the two entities contribute some information to derive the shared session key. Since it is an identity-based key exchange protocol, it uses user's identity or some other information combined with his identity as one's public key to achieve user authentication and key exchange. Thus, a verifier does not verify the certificates of the public keys. A secure and efficient e-cash system plays an important role to support e-commerce safely as a trustful payment over the Internet. In e-cash system, there are three basic entities, customer, bank and merchant. And there are also three activities, withdrawal, payment and deposit. A customer withdraws electronic coins from bank and pays the coins to a merchant in the on-line or on-line manner. Finally, the merchant deposits the paid coins to a bank. In this process, there are many requirements which are anonymity, anonymous revocation, double spending prevention, on-line usage, transferability, divisibility and so on. Here we propose an ECDLP based e-cash system which satisfies all these properties. Deniable authentication protocol is a new security authentication mechanism has two important features (i) it enable an intended receiver to identify the sourceof a given message and (ii) the intended receiver can not prove to any third party the identity of the sender. Finally the implementation issues for these protocols have been discussed. The comparative analysis of our proposed protocols has been made with other existing protocols. In general the proposed protocols are more computationally efficiently and can be more suitable for low processing devices.

E-Mail Address jayaprakashkar (at)
Last Change 2011-03-14 14:02:21
To provide an update on this entry, please click .

Contact: phds (at)

[ IACR home page ] [ IACR PhDs page ] © IACR