A SECURE FRAMEWORK WITH KEY- AGGREGATION FOR DATA SHARING IN CLOUD

A SECURE FRAMEWORK WITH KEY- AGGREGATION FOR DATA SHARING IN CLOUD Yerragudi Vasistakumar Reddy 1, M.Purushotham Reddy 2, G.Rama Subba Reddy 3 1 M.tech Scholar (CSE), 2 Asst.Professor, Dept. of CSE, Vignana Bharathi Institute of Technology (VBIT),Vidya Nagar, Pallvolu, Proddatur, Kadapa (Dist),Andhra Pradesh (India) 3 Working as Associate Professor and Head of Department (CSE), Vignana Bharathi Institute of Technology (VBIT),Vidya Nagar, Pallvolu, Proddatur, Kadapa (Dist), Andhra Pradesh (India) ABSTRACT Data sharing plays a vital role in the cloud computing. In this article we describe that how the data is transferred or shared securely and efficiently from one cloud storage to another cloudstorage. In this articlewe introduce a new public-key cryptosystems which produces the constant-size cipher texts such that reliable delegation of decryption for any set of cipher texts are possible or Capable. The Real theme is that one can aggregate any number of secret keys and make them as a compact as a single key, but to include something new the power of all the keys being used. Apart from this, the secret key holder or user can realise that a constantsize aggregate or occur ate key for cable of being changing the choices of the cipher text set in to the cloud storage, but the other encrypted file or document which is maintained outside will remain secure. This original aggregate key can be freely and conveniently sent to the other storage device or being stored in a smart card with very limited secure storage. In this paper we introduced some secure analysis of our schemes in the standard model. In this paper i.e., in particular, our schemes give the public-key patient that is controlled encryption for flexible hierarchy, which was to be known. I. INTRODUCTION Cloud storage has become popular now a day. In this enterprise, we can see the increase in the demand for data outsourcing, which assists in the strategic management of corporate data. The cloud storage can also been used as a core technology behind many online services for personal applications like desktop applications. In this generation many of the users are sharing there photo albums etc. at this time it is easy to apply for the free accounts for email, photo sharing, file sharing with the size more than 25GB.In this present world and the technology all the user can access all the files and stuff by this cloud storage. Sharing the data is an important functionality in the cloud storage. For example let us consider the Facebook here the social networking sites has become fame in the society and here in Facebook we share the files and pictures that are stored in the cloud storage. Here the challenging problem is that how to share the data securely. So here the data is first converted to encrypted form which can t be understand by the user and finally this encrypted data is converted in to decrypted format and meanwhile here we provide some security like asking for the public key or some security questions and file will be securely sent to the other user. 104 P a g e

II. CRYPTOGRAPHIC KEYS FOR A PREDEfiNED HIERARCHY The main theme of the cryptographic key or security of the data in this phase is toprovide the security of a user data. In cryptographic system is to reduce the cost of a storing the key and managing the security. Secrete key for the purpose of cryptographic. In basic structure of tree hierarchy containing nodes and sub nodes.granted permissions of a main node then share files in descent nodes. III. COMPACT KEY IN SYMMETRIC-KEY ENCRYPTION Compact key symmetric key encryption problem is supporting hierarchy flexible delegation power of decryption. Benaloh was proposed an encryption scheme it mainly apply for trans mitting large number of keys in broadcast of telecommunication. In compact key encryption is tried to minimize the size of symmetric encryption in authentication. IV. COMPACT KEY IN IDENTITY-BASED ENCRYPTION It is the one type of public key encryption is identity based encryption. In this a user can send identity string through secure mail. In middle adjust a trusted party is called private key generator. In identity based encryption user holds a secure master secrete key, secrete key issue based on the trustee authentication, user encrypt the public key with message and receiver decrypt the cipher text with help of secrete key. V. ATTRIBUTE BASED ENCRYPTION In attribute based encryption user encrypt the code cipher text and along with one attribute, master secret key user separate a secret key based on a policy of this attributes, so cipher text decryption can be based on the related attribute conforms of the method. VI. KEY-AGGREGATE ENCRYPTION Here in this encryption technique first we give the framework and definition for key-aggregate encryption. After that we discuss about how to use KAC i.e, key-aggregate Encryption in a scenario of its application in its cloud storage. Framework: In this framework a key aggregate encryption scheme consists of five polynomial-time algorithms. The data owner creates the public key via setup and generates a master-secret key pair via KeyGen. Messages can be encrypted what cipher text class is associated with the plain text message to be encrypted. Here the file is shared using KAC and the key aggregation is useful when we expect the delegation to be efficient and flexible and is finally shared another user secure. In this paper, we know that how to make decrypt keyis more secure in the sense that allows the decryption of multiple cipher texts, without changing its size. In order to solve the issue we have introduced a special type of key i.e., Public-Key cryptosystem or key aggregate cryptosystem It will send or shares the data securely because we are using KAC and the user encrypt a message not only under public-key,but also under an identifier of cipher text which is called as class. 105 P a g e

Here in this existing system we are having the encryption and decryption key in order to share the data securely but the size of the file is increased that has been improved by this paper. We are going to increase the security and privacy level of the data and meanwhile the size of the file will also maintain constantsecurely providing access to the users. 1. Setup Phase: Here in this phase the data owner will execute this phase for an registered account which is not trusted whether the user is genuine or not. The setup phase will have the algorithm that takes only the implicit parameters. 2. KeyGen Phase: Here in this phase the KeyGen will be executed by the above data owner and enters the Public Key(pk) or the Master Key(msk). 3. Encrypt Phase: Here in this phase the Encryption will be executed by everyone who got registered and who wants to send the data from sender to receiver. Encrypti.e,(pk,m,i), the encryption algorithm takes the input parameters as public key(pk), message(m) and the output will be cipher text(c). This algorithm will encrypt themessage m and the cipher text C and along with this the public key which should assigned by sender will also be send to the receiver. 4. Decrypt Phase: Here in this phase the decryption will be executed firstly we will enter the public key and the cipher text and the public key combine and gets the output of the original file. This decrypt phase will take the input as public parameters pk, as a cipher text C, i and the output will be the message m and the final output or file can be received for the receiver after the Decryption process. VII. DATA SHARING KAC which means for Data sharing. Here the data owner can share the data very securely and confidently because KAC is the better way for secure the data to transfer the delegation authority. For sharing the data on the server first the setup phase will be execute and a public key is generated using KeyGen.The master key is kept secret and while decryption the receiver will enter the secret key and combing this two i.e., public key and the cipher text the original file is displayed. When the aggregate key he enters then the user can view the file and download the file with the same file size in a secure manner. VIII. FUTURE IMPLEMENTATION In KAC limited that is predefined bound andcontains more number of a cipher text classes which is limited. In cloud storage day by the number of users login and mean while user s upload data has been increasing rapidly so that number cipher text also increasessimilarly. So in future extension developing there should be the fixed cipher classes. In the present paper cipher text and encrypted data is limited to fixed size, so if anyone knows the key size or File size then the remaining File size and key size will be same. So in future implementation independent length for all cipher text, another problem is secure sending delegates sending secure with sending mail and another secure device. If one key is broken automatically code will be change so use secures in future extensions. 106 P a g e

IX. ARCHITECTURE Here from the above architecture the sender is sharing the each individual file with its own key every file has its own file name and key by using the Key Aggregate Generator and this all the files are stored in the cloud storage by using the concept of the cloud computing. This all the files are securely stored in the cloud storage in network storage and meanwhile the file size will not be increased it will maintain constant at the time of the encryption.messages can be encrypted what cipher text class is associated with the plain text message to be encrypted. Here the file is shared using KAC and the key aggregation is useful when we expect the delegation to be efficient and flexible and is finally shared the another user securely. Here we use the Key Aggregate cryptosystem algorithm to generate a key and meanwhile to share the data securely and the size of the data will not be increased while encrypting or decrypting. The sender will send only the wanted files to the receiver and stop the unwanted files.from the receiver side the receiver will receive the files that are sent by the sender The receiver while viewing the file or images the receiver should enter the key while decryption once the receiver enter the key if the key matches the receiver can view the file and meanwhile download the file. X. CONCLUSION Here protecting the user s data privacy is a major question of the cloud storage. With the help of the more mathematical tools, cryptographic schemes are getting more important and often involve the multiple keys for a single application. In this paper, we consider how to compress the secret keys in public-key cryptosystems which supports delegation of secret keys for different cipher texts in the cloud storage. Here our main approach is more flexible than the hierarchical key and security. 107 P a g e

REFERENCES [1]. L. Hardesty, Secure computers aren t so secure, MIT press,2009, http:// www.physorg.com/ news176107396.html. [2]. D. Boneh and M. K. Franklin, Identity-Based Encryption from the Weil Pairing, in Proceedings of Advances in Cryptology CRYPTO 01, ser. LNCS, vol. 2139. Springer, 2001, pp. 213 229. [3]. ] T. Okamoto and K. Takashima, Achieving Short Ciphertexts or Short Secret-Keys for Adaptively Secure General Inner-Product Encryption, in Cryptology and Network Security (CANS 11), 2011, pp. 138 159. [4]. Data sharing in cloud storage with key-aggregate cryptosystem. Mrs.Komal Kate, Prof. S. D. PotdukhePG Scholar, Department of Computer Engineering, ZES COER, pune, Maharashtra Assistant Professor, Department of Computer Engineering, ZES COER, pune, Maharashtra. [5]. R. Canetti and S. Hohenberger, Chosen-Ciphertext Secure ProxyRe-Encryption, in Proceedings of the 14th ACM Conference oncomputer and Communications Security (CCS 07). ACM, 2007, pp. 185 194. [6]. Key-Aggregate Cryptosystem for Scalable Data Sharing in Cloud Storage Cheng-Kang Chu, Sherman S. M. Chow, Wen-GueyTzeng, Jianying Zhou, and Robert H. Deng, Senior Member, IEEE. AUTHOR DETAILS Yerragudi Vasistakumar Reddy pursuing M.Tech (CSE) Vignana Bharathi Institute of Technology (VBIT),VidyaNagar, Pallvolu, Proddatur, Kadapa (dist),andhra Pradesh 516 362 M. Purushotham Reddy received his M.Tech (Computer Science & Engineering) from Jawaharlal Nehru Technology University, Anantapuramu and pursuing Ph.D in JNTUA, Anantapuramu. Presently he is working as Associate Professor in Computer Science & Engineering, Vignana Bharathi Institute of Technology, Proddatur, Kadapa dist, A. P., India. G.RamaSubbaReddy received his M.E (Computer Science &Engineering) from Sathyabama University, Chennai.Presently he is working as Associate Professor and Head of the Department in Computer Science & Engineering, Vignana Bharathi Institute of Technology, Proddatur, Kadapa Dist.,A.P, INDIA 108 P a g e