ISSN(Online): 2320-9801 ISSN (Print): 2320-9798 International Journal of Innovative Research in Computer and Communication Engineering (An ISO 3297: 2007 Certified Organization) Vol. 3, Issue 4, April 2015 Copyright to IJIRCCE 10.15680/ijircce.2015.0304021 2812 Data Security in Proactive Network using Secret Sharing Mechanism Himanshu Gupta 1 , Vasudha Arora 2 M. Tech Scholar, Dept. of CSE, Manav Rachna International University, Faridabad, India 1 Assistant Professor, Dept. of CSE, Manav Rachna International University, Faridabad, India 2 ABSTRACT: For most of the cryptosystems, using a single master key system is not enough to protect important documents, there is a need of many encryption and decryption keys for this purpose. A Secret Sharing Scheme is the method which divides the secret into several parts and distributes them among the specific communicating entities in such a way that only these participants can reconstruct the secret by poling there share. Hence, unauthorised entity cannot reconstruct the secret. The best way to implement such a system is in cloud environment. Shamir’s(t, n) threshold scheme is one of the most well -known and widely used example of secret sharing systems. KEYWORDS: Secret Sharing; Shamir’s secret sharing scheme; shared key; secret key; I. INTRODUCTION Security is concerned with the ability of a system to prevent it from unauthorized access to information and services. Confidentiality, Integrity and Authenticity are fundamental objectives of security. Many group-oriented applications require communication confidentiality, means that the information of a group should not be exposed to any outsider, but the question is whom to trust. There are many examples when even well-established trusted entities also become malicious. One solution to such a problem is instead of placing trust in just one party to distribute the trust among a group of trusted entities. There are several known cryptographic concepts that address the question for distribution of secret. Some of them are secret sharing schemes, verifiable secret sharing schemes, and multiparty computation [1]. Although a well-known term within the cryptographic community, secret sharing might be a bit misleading for an outsider [2]. It does not mean two or more people sharing one secret. It means two or more people are having shares of the secret. One secret is split into n different shares. Ideally, it should be impossible to gain any information about the secret with less than n shares. To provide fundamental objectives of security one-time session keys need to be shared among communication entities to encrypt and authenticate secrets. Thus, before exchanging communication messages, a key establishment protocol needs to issue a one-time secret session keys to all participating entities. The key establishment protocol also needs to provide confidentiality and authentication for session keys. There are two types of key establishment protocols: key transfer protocols and key agreement protocols. Key transfer protocols rely on a mutually trusted key generation centre (KGC) to select session keys. KGC sends the session keys to all other shareholders of the original secret. In key agreement protocols, all communication entities are involved to determine session keys [5]. To explain secret sharing consider the example: Suppose you and your friendhave a joint account in which you have deposited your money. If both have passwords for that account or anyone have password for that account then you are worried about the integrity of your friend that he might withdraw all the money and cheat you and so as your friend. Now who is going to keep the password? Now, we need a scheme such that the password is shared between both of you in such a way that both shares of password are required in order to open that account. Individual shares will be useless. Now, you and your friend can be assured that the other will not take all the money without the consent of both. This illustrates the concept of secret sharing.