KEY-AGGREGATE CRYPTOSYSTEM FOR SCALABLE DATA SHARING IN CLOUD STORAGE

ABSTRACT:

Data sharing is an important functionality in cloud storage. Inthis article, we show how to securely, efficiently, and flexibly share datawith others in cloud storage. We describe new public-key cryptosystemswhich produce constant-size ciphertexts such that efficient delegationof decryption rights for any set of ciphertexts are possible. The noveltyis that one can aggregate any set of secret keys and make them ascompact as a single key, but encompassing the power of all the keysbeing aggregated. In other words, the secret key holder can releasea constant-size aggregate key for flexible choices of ciphertext set incloud storage, but the other encrypted files outside the set remainconfidential. This compact aggregate key can be conveniently sent toothers or be stored in a smart card with very limited secure storage. Weprovide formal security analysis of our schemes in the standard model.We also describe other application of our schemes. In particular, ourschemes give the first public-key patient-controlled encryption for flexiblehierarchy, which was yet to be known.

EXISTING SYSTEM:

Considering data privacy, a traditional way to ensureit is to rely on the server to enforce the accesscontrol after authentication,which means any unexpected privilege escalation will expose all data. Ina shared-tenancy cloud computing environment, thingsbecome even worse. Data from different clients can behosted on separate virtual machines (VMs) but resideon a single physical machine. Data in a target VM couldbe stolen by instantiating another VM co-resident withthe target one. Regarding availability of files, thereare a series of cryptographic schemes which go as far asallowing a third-party auditor to check the availabilityof files on behalf of the data owner without leakinganything about the data, or without compromisingthe data owner’s anonymity. Likewise, cloud usersprobably will not hold the strong belief that the cloudserver is doing a good job in terms of confidentiality. Acryptographic solution, with proven security reliedon number-theoretic assumptions is more desirable,whenever the user is not perfectly happy with trustingthe security of the VM or the honesty of the technicalstaff. These users are motivated to encrypt their datawith their own keys before uploading them to the server.

DISADVANTAGES OF EXISTING SYSTEM:

  • Unexpected privilege escalation will expose all
  • It is not efficient.
  • Shared data will not be secure.

PROPOSED SYSTEM:

The best solution for the above problem isthat Alice encrypts files with distinct public-keys, butonly sends Bob a single (constant-size) decryption key.Since the decryption key should be sent via a securechannel and kept secret, small key size is always desirable.For example, we cannot expect large storagefor decryption keys in the resource-constraint deviceslike smart phones, smart cards or wireless sensor nodes.Especially, these secret keys are usually stored in thetamper-proof memory, which is relatively expensive. Thepresent research efforts mainly focus on minimizingthe communication requirements (such as bandwidth,rounds of communication) like aggregate signature.However, not much has been done about the key itself.

ADVANTAGES OF PROPOSED SYSTEM:

  • It is more secure.
  • Decryption key should be sent via a securechannel and kept secret.
  • It is an efficient public-key encryption scheme whichsupports flexible delegation.

SYSTEM ARCHITECTURE:

SYSTEM CONFIGURATION:-

HARDWARE REQUIREMENTS:-

Processor-Pentium –IV

Speed-1.1 Ghz

RAM-512 MB(min)

Hard Disk-40 GB

Key Board-Standard Windows Keyboard

Mouse-Two or Three Button Mouse

Monitor-LCD/LED

SOFTWARE REQUIREMENTS:

•Operating system:Windows XP

•Coding Language:Java

•Data Base:MySQL

•Tool:Net Beans IDE

REFERENCE:

Cheng-Kang Chu, Sherman S. M. Chow, Wen-Guey Tzeng, Jianying Zhou, and

Robert H. Deng, “Key-Aggregate Cryptosystemfor Scalable Data Sharing in Cloud Storage”IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS, Vol:25,Issue: 2, Feb. 2014.