International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 02 Issue: 04 | July-2015 www.irjet.net p-ISSN: 2395-0072 © 2015, IRJET.NET- All Rights Reserved Page 40 SECURE DATA SHARING USING AGGREGATE KEY FOR SENSITIVE DATA M.R.Sumalatha 1 , M.B.Rizvana Begam 2 , E.Divya Priya 3 , J.Bejin Joe 4 1 Associate Professor,Information Technology Department, Anna University,Tamil Nadu,India 2,3,4 Students, Information Technology Department, Anna University,Tamil Nadu,India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - Security is essential for sharing sensitive data in the cloud. Using the aggregate key, makes the system share the sensitive data without transferring keys for each and every file. This system uses asymmetric encryption standard for encrypting all the data followed by public key encryption. The end user can access their data using their private key and the master secret key which is transferred during or after authentication process. Even though the Master secret key is hacked during transmission, the malicious attacker cannot get the data since it can be decrypted only by using a private key. There is no need to transfer key for each and every file. All data will be encrypted by the Master Secret Key. So data will be safe at a remote place. Users who need sensitive data will access the data using their private key so there is no need to transfer key for each and every file. Key Words: Aggregate Key, Cassandra, Data Sharing, Security, Sensitive data. 1. INTRODUCTION Data security involves digital privacy measures that protect sensitive digital data from corruption. These measures are applied to protect computers and databases from unauthorized access. Organizations irrespective of the size or genre mainly prioritize Data Security. Data security has different nomenclatures like information security or computer security. User’s outsource confidential data in cloud servers and hence it requires protection from unauthorized access by malicious attackers. The impact of data confidentiality is not only restricted to security and privacy issues but also to juristic concerns. In cloud computing, Data sharing is an essential aspect for secure, efficient and flexible sharing of data with the other authorized users. New public-key cryptosystems produce cipher texts which are of constant size so that decryption rights for sets of cipher texts can be efficiently delegated [3]. The idea proposed is that the user can gather any set of secret keys and compact them into a single key. This single key comprises the power of all the secret keys which are aggregated.The user who possesses the secret key is allowed to release a constant-size aggregate key so that cipher text set can be flexibly chosen while ensuring that the other encrypted files out of the set stay confidential. The constant-size aggregate key which is released by the user can be easily directed to other users or it can be saved in a smart card. It can perform security analysis of the schemes which are in the standard model. The data to be shared is mostly sensitive, which is accessible only to a certain level. For example, the data used in business intelligence, health system, bank transactions are highly sensitive. These sensitive data must be shared in a highly secured manner. To maintain confidentiality of user's sensitive data, existing techniques employ cryptographic methods by exposing decryption keys only to the authorized data owners and users [10]. In this paper, a method to share data in a highly secured manner is proposed, using an aggregate key instead of using the separate keys of each file. This reduces the time for transferring the keys and improves performance of sharing data. 2. RELATED WORK The survey has been carried out on data sharing issues in a confidential manner, Privacy-Preserving Public Auditing is being analyzed [1]. In their system a secure cloud storage method is proposed which supports privacy- preserving public auditing. Existing systems make use of a TPA (third party auditor) to satisfy auditing requirements for any number of users in a parallel and efficient manner. Users can access the cloud infrastructure as if it is in their own local domain without bothering to check its integrity. Service providers cannot attend auditing requests of all its users. Hence, SP relies on TPA, which performs batch- auditing to deal with the auditing requirements of the users. However, the third party auditors are susceptible to compromise in the security of the outsourced data. The system uses homomorphic linear authenticator along with random masking. This can guarantee that the TPA (third party auditor) is restricted from learning any knowledge about the outsourced data. Data security of systems with multiuser setting is threatened as the privacy-preserving public auditing protocol cannot be extended to future extensive cloud storage as it lacks efficiency. Trusted computing aims to address the problem of trustworthy online computing through the use of