IJIRST –International Journal for Innovative Research in Science & Technology| Volume 2 | Issue 11 | April 2016 ISSN (online): 2349-6010 All rights reserved by www.ijirst.org 759 Securing Data Deduplication on Hybrid Cloud using Asymmetric Key Algorithm Prakash Gapat Snehal Khillare Department of Information Technology Department of Information Technology Pimpri Chinchwad College of Engineering,Akurdi, Pune Pimpri Chinchwad College of Engineering,Akurdi, Pune Akshay Khiste Mrs.Rohini Pise Department of Information Technology Department of Information Technology Pimpri Chinchwad College of Engineering,Akurdi, Pune Pimpri Chinchwad College of Engineering,Akurdi, Pune Abstract Data deduplication is an effective compression tech-nique to eliminate duplicate copies of repeating data.It has been widely used in cloud storage to reduce the amount of storage space and save bandwidth. For the protection of sensitive data while supporting deduplication, the convergent encryption technique is being used to encrypt the data before outsourcing it to cloud storage.In order to make system more secure, the different privileges of users are again considered while checking duplicate content.But the problem which occurs in this approch is that int this we use symmetric key encryption technique to encryts and decrypts data.In this only single key is used for encryption and dycryption , This key can be misused. So we are using public key cyptography method in this approch the file is encrypted by using public key and drypted by using private key this two different keys are generated on private cloud. Keywords: Deduplication, authorized duplicate check, confidentiality, hybrid cloud _______________________________________________________________________________________________________ I. INTRODUCTION Cloud computing means sharing of resource over the net-work. This technology is very popular now days. The various companies , industries and even in government system it is commonly used. It can be used for various kind of resources like computing power, storage or various software .It provides the very large amount of space. Now days the storage pro-viding service is very popular and it is widely used. The main problem in this is to efficiently use this space which are available on cloud or we need to buy another storage space on cloud. This increasing space can be difficult to manage as well as the cost of buying resources is increases as companies required large storage for working and fulfilling request of customer. To solve this problem we use the data deduplication technique..Data deduplication used on the data either on block level or file level. In file level approach duplicate files are deleted and only one authenticate copy is store which is share between the users, and in block level approach duplicate blocks are eliminated of non-identical files. Deduplication reduce the storage needs by upto 90-95 % for backup application,68% in standard file system and thus we generate more space for our file. Important issues in data deduplication is to provide the security and privacy to protect the data from insider or outsider attacker .For data confidentiality ,encryption techniques is used by different users for encryption on there files or data ,using a key users perform encryption and decryption operation using various cryptography methods. For uploading file to cloud user first generate convergent key in existing system this key is used for encryption as well as in the decryption .The key encrypts the file then user upload file on the cloud. To prevent illegal unauthorized access on cloud we use the proof of ownership protocol to provide proof that the confirmation of user that this user indeed owns the same file when deduplication occurs and wants to download file. After this , server provide a pointer to subsequent user for accessing same file without needing to upload same file so we are also save the bandwidth .When a user wants to download a file from cloud he just login into system and select file for download that is in encrypted file form so user decrypt this file using convergent key. To make information administration versatile in distributed computing, deduplication has been an understood system and has pulled in more consideration as of late. Information deduplication is a technique used on some information and pressure procedure for disposing of copy duplicates of rehashing information away. The procedure is utilized to enhance stockpiling us-age and can likewise be connected to network information exchanges to diminish the quantity of bytes that must be sent. Rather than keeping various information duplicates with the same substance, deduplication wipes out excess information by keeping one and only physical duplicate and alluding other repetitive information to that duplicate. II. EXISTING SYSTEM Convergent encryption Convergent key encryption is used for encrypts and decrypts data.User derives a key that is conergent key from the original data copy by using some algorithms in this case we are using SHA algorithm for generating hash value which is used as convergent key. We encrpty data using this key.Also user derives a tag from using this key and user id to check weather this data is duplicate or not.If tag are same then the data is already present on the cloud. Both convergent key and tag are use for duplication check. Convergent encryption, also known as content hash keying, is used to produces identical ciphertext which is