© 2013, IJARCSSE All Rights Reserved Page | 919 Volume 3, Issue 5, May 2013 ISSN: 2277 128X International Journal of Advanced Research in Computer Science and Software Engineering Research Paper Available online at: www.ijarcsse.com Cloud Computing Security potential for migration from a single cloud to a Multi-Cloud Environment B.Srinivasulu #1 , S.V.SRIDHAR #2, U.Narasimhulu #3, K.Ramakrishna #4 Hyderabad(A.P),India Abstract – this paper we propose and evaluate The use of cloud computing has increased rapidly in many organizations. Cloud computing provides many benefits in terms of low cost and accessibility ofdata. Ensuring the security of cloud computing is a major factor inthe cloud computing environment, asusers often store sensitive information with cloudstorage providers but these providers may beun trusted. Dealing with “single cloud” providers ispredicted to become less popular with customers dueto risks of service availability failure and thepossibility of malicious insiders in the single cloud. Amovement towards “multi-clouds”, or in other words,“Inter clouds” or “cloud-of-clouds” has emergedrecently.This mainly focuses on the issues related to the data security aspect of cloud computing. As data and information will be shared with a third party, cloud computing users want to avoid a untrusted cloudprovider. Protecting private and important information, such as credit card details or a patient’s medical records from attackers or malicious insiders is of critical importance. In addition, the potential for migration from a single cloud to a multi-cloud environment is examined and research related to security issues in single and multi-clouds in cloud Computingis surveyed. Keywords:, Secret Shring Algoritham, Byzantine Protocol, Byzantinefault tolerance, Integrity Layer. I. Introduction The use of cloud computing has increased rapidly in many organizations Cloud providers should address privacy and security issues as a matter of high and urgent priority. Dealing with “single cloud” providers is becoming less popular with customers due to potential problems such as service availability failure and the possibility that there are malicious insiders in the single cloud. In recent years, there has been a move towards “multi clouds”, “inter cloud” or “cloud -of-clouds”. This paper focuses on the issues related to the data security aspect of cloud computing. As data and information will be shared with a third party, cloud computing users want to avoid a un trusted cloud provider. Protecting private and important information, such as credit card details or a patient‟s medicalrecords from attackers or malicious insiders is of critical importance. In addition, the potential for migration from a single cloud to a multi-cloud environment is examined and research related to security issues in single and multi-clouds in cloud computing is surveyed. Cloud service providers should ensure the security of their customers‟ data and should be responsible if any security risk affects their customers‟ serviceInfrastructure. A cloud provider offers many services that can benefit its customers such as fast access to their data from any location, scalability, pay-for-use, data storage, and data recovery, protection against hackers, on-demand security controls, and use of the network and infrastructure facilities In this we are using “Secret Shring Algoritham “it is used how to store the data in different clouds. It is one type of crypto graphic algorithm and it is used in security purpose. In this we are using “byzantine fault tolerance protocol” it is used check the traffic in to the clouds. In this using one formula‟ 3*f+1‟in this „f‟ means fault probability. Background: Cloud computing as “a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction”. The cloud Secret sharing algorithm: Data stored in the cloud can be compromised or lost. So, we have to come up with a way to secure those files. We can encrypt them before storing them in the cloud, which sorts out the disclosure aspects. However, what if the data is lost due to some catastrophe befalling the cloud service provider? We could store it on more than one cloud service and encrypt it before we send it off. Each of them will have the same file. What if we use an insecure, easily guessable password to protect the file, or the same one to protect all files? I have often thought that secret sharing algorithms could be employed to good effect in these circumstances instead. They are algorithms that will share a secret between several parties, such that none of them can know the secret without the