IOSR Journal of Computer Engineering (IOSR-JCE) e-ISSN: 2278-0661, p- ISSN: 2278-8727Volume 13, Issue 5 (Jul. - Aug. 2013), PP 14-20 14 | Page Cryptographic Cloud Storage with Hadoop ImplementationSowmya. D, II-MCA, IFET College of Engineering. Abstract: Cloud storage enables users to remotelystore their data and enjoy the on-demand high quality cloud applications without the burden of local hardware and software management. Though the benefits are clear, it inevitably poses new security risks toward the correctness of the data in cloud. To address this problem, the proposed design allows users to audit the cloud storage with very lightweight communication and computation cost by utilizing the new cryptographic technique like homomorphic token and distributed erasure-coded data. By introducing the notion of parallel homomorphic encryption (PHE) schemes, which are encryption schemes that support computation over encrypted data via evaluation algorithms that can be efficiently executed in parallel. In addition, we can hide the function being evaluated with the MapReduce model runnable on Hadoop framework for element testing and keyword search. Analysis shows the proposed scheme is highly efficient and resilient against Byzantine failure, malicious data modification attack, and even server colluding attacks and attempting to strike a balance between security, efficiency and functionality using Kerberos protocol and HDFS system. I.IntroductionIn the problem of private outsourced computation, a client wishes to delegate the evaluation of a function f on a private input x to an untrusted worker without the latter learning anything about x and f(x). This problem occurs in many applications and, most notably, in the setting of cloud computing, where a provider makes its computational resources available to clients as a service". One approach to this problem is via the use of homomorphic encryption (HE). An encryption scheme is homomorphic if it supports computation on encrypted data, i.e., in addition to the standard encryption _Work done at Microsoft Research. The decryption algorithms has an evaluation algorithm that takes as input an encryption of some message x and a function f and returns an encryption of f(x). HE schemes can be roughly categorized into two types. The first is arithmetic HE schemes which, in addition to the standard encrypt and decrypt operations, have an add or multiply operation that take as inputs encryptions of messages x1 and x2 and returns encryptions of x1+x2. If an arithmetic HE scheme supports both addition and multiplication, then it can evaluate any arithmetic circuit over encrypted data and we say that it is a fully homomorphic encryption (FHE) scheme. We refer to the second type of HE schemes as non-arithmetic since they do not provide (at least explicitly) addition or multiplication operations.