• Bhushan Patil
• Gajanan Kuntewad
• Imran Shaikh
• Siddesh Rane
• Prof. R. S. Gute

In cloud computing environment there are many users of cloud stores there data and accessing of large data stored on cloud. But these users face some of major issue causing loss of data in cloud and facing a problem in authority and privacy of users. Cipher text-Policy Attribute based Encryption (CP-ABE) is a promising encryption technique that enables end-users to encrypt their data under the access policies defined over some attributes of file and upload encrypted file with encrypted attribute with key provided by attribute authority. Cloud consumers want to download and only allow data consumers whose attributes satisfy the access policies to decrypt the data. In CP-ABE, the access policy is attached to the cipher text in plaintext form, which may also leak some private information about end-users. Existing methods only partially hide the attribute values in the access policies, while the attribute names are still unprotected, these issues are modify in our scheme to provide more security. While uploading a file time server is associated with file to provide access to file for limited time only after that time file is unavailable for consumers. Also attribute bloom filter generate attributes of file while uploading and this attributes are store with file. Attribute authority in our scheme assign public key to user while uploading files on cloud and also files secret key and private key to data consumer while uploading. After entering keyword consumer will get top rank result depends upon attribute and time and can download that file if consumer having key of that file and can decrypt file.

"A Secure Encryption Scheme for Data Sharing in unreliable cloud Environment", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.5, Issue 12, page no.262-266, December-2018, Available :http://www.jetir.org/papers/JETIR1812539.pdf

"A Secure Encryption Scheme for Data Sharing in unreliable cloud Environment", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.5, Issue 12, page no. pp262-266, December-2018, Available at : http://www.jetir.org/papers/JETIR1812539.pdf