1. INTRODUCTION:

Normally cloud is internet related development technology. It is new computing style for users, in which resources are provides by the internet as a services [1]. The main service in cloud is to provide storage space to user for storing or outsource data. For example, a company permits their staff to store files in cloud storage. In this situation it also gives important risk for stored files confidentiality [2]. Particularly, the cloud servers that is managed by cloud provider is not entirely trusted by users when their data files is stored in the cloud storage. Because of that record may have confidential and sensitive data, such as medical or business plans. To protect privacy of data, basic idea is to encrypt the data files before stored and outsource the encrypted data into cloud storage [3].

In some existing system, cryptographic system has been offered that provides the secure data sharing on untruthful servers related on the methods that split the files into some files group and encrypting every file group with file block key [4].The joined methods of KP-ABE, lazy re-encryption and proxy re-encryption is used to accomplish the fine grained access control for data without revealing contents of data. In this system, we suggest data sharing methods that can provide protected key sharing and data distribution for dynamic group users [5]. In this we suggest a secure sharing scheme for data that can be secured from conspiracy attack. The withdraw users can not be get the real data once they are withdrawer even if they combine with the un trusted cloud [6].To overcome the issues offered above, this system suggests a creative method for more owner secure data sharing method for dynamic groups in cloud computing. It can be done by ABE (Attribute based encryption) in which every data files will be encrypted beside with relevant attributes to data file [7]. When the time of decryption, the user have to gives applicable attributes that satisfies the data file access structure.

RELATED WORK:

In this section we have discussed some previous our related on our system. In [8] distributing resource along with cloud users is a important issues, so cloud provide an efficient and economical solution. Because of the regular membership change, distributing data in multi-owner way to an untruthful cloud is important problem. In their suggests a safety multi-owner scheme for data sharing, for dynamic user group in cloud storage. By using AES encryption technique when store the date on cloud, any user can safely distribute data with other users. In the mean time, the overhead of storage and cost of encryption computation are independent with no of withdrawer users. In [9] they build a scheme of short group signature. Signatures in their scheme are roughly the standard RSA signature size with similar security. Group signature security is related on the strong Diffie-Hellman supposition and a new supposition in bilinear groups called the DLA (Decision Linear Assumption).

They prove their system security, in the model of random oracle, using a security modification definition for collection signature freshly given by Miccianicio, Warinshchi and Bellare. In [10] suggested an application called atomic re-encryption proxy, in that a trusted proxy changed a cipher text for Bob into a cipher text to Alice without considering the essential plaintext. They prevent that secure and fast re-encryption will develop into increasingly trendy as a scheme for running encrypted file model. In [11] with low maintenance character, cloud computing gives an efficient and economical answer for distributing group sources along with cloud users. Unluckily, distributing data in multi-owner way when protecting privacy identity and data from an untruthful cloud is important problem and it is because of the regular membership modification. They suggest a safety multi owner scheme for data sharing, named Mona, for dynamic user groups in cloud storage. By using group signature and techniques dynamic broadcast encryption, any user can namelessly distribute data with other users. In [12] CP-ABPRE extends the PRE (proxy re-encryption encryption) by permitting a proxy of semi-trusted to converts a cipher text less than an entrance policy to the one user with equal plaintext under policy of another access. The proxy nothing learn anything about that plaintext. CP-ABPRE has more real application in real world, such as re-grained control access in cloud system and medical information distribution with various hospitals. Existing CP-ABPRE schemes go away how to safety next to selected-cipher text issues as an unlock problem.

PROPOSED WORK:

OVERVIEW:

This system uses a safety data distributing method that can accomplish secure data and key sharing for dynamic user groups. We suggest a safety data distributing method that can be confined from conspiracy issue. This system uses an creative scheme for safety multi-owner scheme for data sharing for dynamically form groups in cloud. By using ABE (Attribute based encryption) technique every data can be encrypted with relevant attribute value of data file. When the decryption, the user have to gives related attributes that meets the data file access structure.

Cloud Service Process:

Cloud service is a internet related computer technology. Using this advantages users can store their sensitive data and shared data in cloud storage. In our proposed system we use cloud service for storing and sharing purpose. Here Group manager is monitor person, he/she can only authorize users for who can upload or access the data in cloud.

Figure1: Overall Architecture

Group Manager:

In this project Group manager is administrator personfor validation the users and provide the permission to users for storing the data. Group manager is authorized person for editing the data in cloud storage. In this system group manager is intermediate person of cloud admin. Every user process logs and file information details are maintained in the group manager side. User authorization and revocation are done in group manager side only.

Group Users process:

Group users are group of registered users they will outsource their private data into cloud storage and they can access or store the data in cloud after the validation in group owner side. Whenever user needs access a file akey will be distributed to user for accessing file. Group users can be changed by group manager. Group users can view the files of whoever in the group.

Key Distribution and Data accessing

In this system we use CP-ABE method for encryption and decryption data. When user needs to encrypt the file the key distributor can only provide the key for encryption at the same way for decryption. If some user needs to access the file that is stored in a cloud storage, user have to get the permission from group manager. That time key distributor provide the key to group manager then group manager forward the key to group user. Here key is send to group user by group manager. Here Register user can only access and edit the file. Every user can access the file using their encryption key. If some users revoke from the group and then they need to access file of that group, again he/she have to register and get key for access the files.

Algorithm Used:

Key Policy Attribute based Encryption:

A key policy attribute based encryption scheme consists of four fundamental

Algorithms: Setup, Key Generation, Encryption and Decryption.

Setup:

The setup algorithm takes no input other than the implicit security parameter. It outputs the public parameters PK and a master key MK.

Key Generation (MK, S):

The key generation algorithm takes as input the master key MK and a set of attributes S that describe the key. It outputs a private key SK.

Encrypt (PK, A,M):

The encryption algorithm takes as input the public parameters PK, a message M, and an access structure A over the universe of attributes. The algorithm will encrypt M and produce a key CT such that only a user that possesses a set of attributes that satisfies the access structure will be able to decrypt the message. Assume that the key implicitly contains A.

Decrypt(PK,CT,SK):

The decryption algorithm takes as input the public parameters PK, a key CT, which contains an access policy A, and a private key SK, which is a private key for a set S of attributes. If the set S of attributes satisfies the access structure A then the algorithm will decrypt the key and return a message M.

EXPERIMENTAL RESULT:

In this section we have discussed our system experimental results with previous work. Sharing the data with other users is efficiently achieved by Attribute based encryption method. By using this system multi user can access the file in cloud storage without more user overhead.

Figure2: Accuracy percentage of Proposed and Existing

The above figure explains our proposed system performance is better than the existing system. In existing system user revocation and joining process takes more time and cost compare with our proposed system. In proposed system using the key distributor we overcome the above problem.

CONCLUSION:

In the proposed system it support to multiple users for communicate with each other users by using data sharing and storing in cloud. Problems in existing systems are block keys of files have to be reorganized and distributed to every user when user revocation; S, that system had more overhead in key distribution. The complexity of this method is increasing when the time of more user participation and revocation. In our proposed system the above complexity is reduced because of when user revocation time there is no operation for key updating to reaming users, every user have a own attribute related encryption and decryption key. Using our propose system we can achieve the computation cost of user revocation and joining process. That is the reason if how many user revoked from group, the other users can decrypt the file more or less remain the same.

REFERENCES:

1. Cong Wang, Wenjing Lou, Shucheng Yu and Kui Ren, “Achieving Secure, Scalable, and Fine-grained Data Access Control in Cloud Computing”, Proc. IEEE Infocom, pp. 534-542, 2010.

2. Simon Caton, Kyle Chard, Omer F. Rana, and Kris Bubendorfer, “Social Cloud Computing: A vision for socially motivated resource sharing”, IEEE Transactions on services computing, vol. 5, no. 4, October, 2012.

3. Qingsong Wei, Lingfang Zeng, Dan Feng Wuhan, and Lingfang Zeng, “SeDas: A Self-Destructing Data System Based on Active Storage Framework”, Ieee Transactions on Magnetics, vol. 49, no. 6, June, 2013.

4. Prashant Pilla, “Enhancing Data Security by Making Data Disappear in a P2P Systems”, Computer Science Department journal, November 2012, Oklahoma State University, Stillwater.

5. A.D. Joseph, A. Fox, M. Armbrust, A.Konwinski, R. Griffith, Patterson and I. Stoica, D.A. and M. Zaharia, “A View of Cloud Computing,” Comm. ACM, vol. 53, no. 4, pp. 50-58, Apr. 2010.

6. K. Lauter, S. Kamara and “Cryptographic Cloud Storage,” Financial Cryptography and Data Security (FC), pp. 136-149, Jan. 2010.

7. J. Shanthini, V. Sathana,” Enhanced Security System for Dynamic Group in Cloud” Int Jou of advanced research in computer science and software engineering, Volume 4, Issue 3, March 2014

8. V. Sathana, J. Shanthini,” Int Jor of advanced research in enhanced security system for Dynamic Group in Cloud”, Volume 4, Issue 3, March 2014 ISSN: 2277 128X.

9. Dan Boneh, Xavier Boyen, Hovav Shacham,” Short Group Signatures”, 2005.

10. Ateniese, Kevin Fu, Matthew Green and Susan Hohenberger,” Improved Proxy Re-Encryption Schemes with Applications to Secure Distributed Storage”, 2006.

11. Mr. K. Janardhan and Mr. M. Narendra M. Tech scholar,” Mona: Secure Multi-Owner Data Sharing for Dynamic Groups in the Cloud,” Int Jor of engineering research and applications (IJERA) ISSN: January 2015.

12. Kaitai Liang, Liming Fang, Duncan S. Wong and Willy Susilo,” A Ciphertext-Policy Attribute-Based Proxy Re-Encryption with Chosen-Ciphertext Security”, 2014.

Received on 21.09.2016 Modified on 10.11.2016

Research J. Pharm. and Tech. 2017; 10(1): 83-86.

DOI: 10.5958/0974-360X.2017.00020.8