6th European Conference - Academic Conferences

A System and Method for Designing Secure Client-Server
Communication Protocols Based on Certificateless PKI
Natarajan Vijayarangan
Tata Consultancy Services Limited (TCS), Chennai, India
n.vijayarangan@tcs.com
Abstract: Client-server networking is a distributed application architecture that partitions tasks or work loads
between service providers (servers) and service requesters (clients), where the network communication is not
necessarily secure. A number of researchers and organizations have produced innovative methods to ensure a
secure communication in the client-server set up. However, in this paper, TCS has brought out a system of novel
network security protocols for a generic purpose. Let us take a look into the brief history of client-server
communication. In 1993 Bollovin and Merritte patented a strong Password-based Authentication Key Exchange
(PAKE), an interactive method for two or more parties to establish cryptographic keys based on one or more
party's knowledge of a password. Later, Standford University patented Secure Remote Protocol (SRP) used for a
new password authentication and key-exchange mechanism over an untrusted network. Then Sun Microsystems
implemented the Elliptic Curve Cryptography (ECC) technology which is well integrated into the OpenSSL-
Certificate Authority. This code enables secure TLS/SSL handshakes using the Elliptic curve based cipher suites.
In this paper, we proposed a set of client-server communication protocols using certificateless Public Key
Infrastructure (PKI) based on ECC. Then the protocols have identity based authentication without using bilinear
maps, session key exchange and secure message transfer. Moreover, we showed that the protocols are
lightweight and are designed to serve multiple applications.
Keywords: certificateless public key cryptography, elliptic curve cryptography, jacobi identity, message
preprocessing, lie algebras, challenge-response
1. Introduction
In the existing network operating systems, communication between the client and server takes place
using File Transfer Protocol mode which is not a secure medium. The more secure medium for
communication, Hypertext Transfer Protocol Secure, also does not ensure the security of messages,
but the connection. For instance, some of the problems that users access with a set-top box unit
would be data loss, content modification and so on. TCS has designed a set of novel network security
protocols to avoid these issues and ensure robust communication between the client and server.
Theoretically and practically, the proposed protocols have been analyzed that these protocols are
secure against replay and rushing attacks. In this design, the certificateless PKI concept based on
ECC (Al-Riyami and Paterson 2003, Hankerson et al 2004) is introduced to strengthen the protocols.
Hence TCS filed up a patent application for this invention.
2. Objectives of the invention
The objectives of the invention are to provide: 1) a secure communication between client and server
2) a robust, tamper-proof and lightweight authentication mechanism, 3) non-repudiation for clients and
4) no password-based negotiation between client and server.
3. Overview of the invention
In the existing network security protocols, certificate-based public key cryptography and Identitybased
cryptography have been widely used. These Crypto methods face the costly and complex key
management problem and the key escrow problem in the real-life deployment. A few years ago,
Certificateless Public Key Cryptography (CL-PKC) was introduced to address these problems, which
have not been solved fully. Sometimes, CL-PKC uses bilinear pairings (Adi Shamir 1984) and inverse
operations which will slowdown the performance of authentication process.
TCS' new approach towards the network security protocols will solve the common problems between
customers and network service providers or agents. Many researchers and organizations have
developed innovative client-server communication protocols based on certificates which require a lot
of computation, power consumption and memory space. TCS has designed a lightweight protocol that
will overcome these issues.
TCS has introduced CL-PKC with no bilinear pairings in the proposed set of network security
protocols. These protocols are efficient and effective against common attacks and have applications
in client-server set up over Transmission Control Protocol and User Datagram Protocol networks, Set-
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