Attribute-based encryption (ABE) is a public-key based one-to-many encryption that allows users to encrypt and decrypt data based on user attributes. A promising application of ABE is flexible access control of encrypted data stored in the cloud, using access polices and ascribed attributes associated with private keys and ciphertexts.One of the main efficiency drawbacks of the existing ABE schemes is that decryption involves expensive pairing operations and the number of such operations grows with the complexity of the access policy. Recently, Green et al. proposed an ABE system with outsourced decryption that largely eliminates the decryption overhead for users. In such a system, a user provides an untrusted server, say a cloud service provider, with a transformation key that allows the cloud to translate any ABE cipher text satisfied by that user’s attributes or access policy into a simple cipher text, and it only incurs a small computational overhead for the user to recover the plaintext from the transformed cipher text. Security of an ABE system with outsourced decryption ensures that an adversary (including a malicious cloud) will not be able to learn anything about the encrypted message; however, it does not guarantee the correctness of the transformation done by the cloud. In this paper, we consider a new requirement of ABE with outsourced decryption: verifiability. Informally, verifiability guarantees that a user can efficiently check if the transformation is done correctly. We give the formal model of ABE with verifiable outsourced decryption and propose a concrete scheme. We prove that our new scheme is both secure and verifiable, without relying on random oracles. Finally, we show an implementation of our scheme and result of performance measurements, which indicates a significant reduction on computing resources imposed on users. http://kaashivinfotech.com/ http://inplanttrainingchennai.com/ http://inplanttraining-in-chennai.com/ http://internshipinchennai.in/ http://inplant-training.org/ http://kernelmind.com/ http://inplanttraining-in-chennai.com/ http://inplanttrainingchennai.com/

1. IEEE TRANSACTIONS ON INFORMATION FORENSICS AND
SECURITY, VOL.8, NO.8, JULY 2014.
Attributes based encryption with verifiable outsourced decryption

2. Abstract
 Attribute-based encryption (ABE) is a public-key based one-to-many encryption that allows
users to encrypt and decrypt data based on user attributes.
 A promising application of ABE is flexible access control of encrypted data stored in the cloud,
using access polices and ascribed attributes associated with private keys and ciphertexts.One of
the main efficiency drawbacks of the existing ABE schemes is that decryption involves expensive
pairing operations and the number of such operations grows with the complexity of the access
policy.
 Recently, Green et al. proposed an ABE system with outsourced decryption that largely
eliminates the decryption overhead for users.
 In such a system, a user provides an untrusted server, say a cloud service provider, with a
transformation key that allows the cloud to translate any ABE cipher text satisfied by that user’s
attributes or access policy into a simple cipher text, and it only incurs a small computational
overhead for the user to recover the plaintext from the transformed cipher text.
 Security of an ABE system with outsourced decryption ensures that an adversary (including a
malicious cloud) will not be able to learn anything about the encrypted message; however, it does
not guarantee the correctness of the transformation done by the cloud. In this paper, we consider
a new requirement of ABE with outsourced decryption: verifiability. Informally, verifiability
guarantees that a user can efficiently check if the transformation is done correctly.
 We give the formal model of ABE with verifiable outsourced decryption and propose a concrete
scheme. We prove that our new scheme is both secure and verifiable, without relying on random
oracles. Finally, we show an implementation of our scheme and result of performance
measurements, which indicates a significant reduction on computing resources imposed on
users.

3. Proposed System
 In the proposed system the evaluation and accuracy of the attributes
are traced in order to provide better encryption/decryption strategy
while transferring data from source to destination.
 The generation of the public and private key using the attributes and
master key with proxies and access structure attributes are same as the
existing system.
 The combination of the public and private key generates the message.
 The verification of the outsourced decryption are also made using the
combination of private key and parameter attribute that generates the
transform and retrieve key similarly as the existing system.
 Additionally the concept of proxy verification are made since the
proxies are intermediate between the source and the destination. The
validation are made using the private key check with the proxies and
the source.
 The attribute used are checked for its uniqueness so as to avoid the
same attribute for the common parametric data.
 the encryption of data are validated using the public. Hence this
system overcomes the drawback of the existing system.

4. Existing System
 In the existing system the concepts of attribute based encryption and
verifiable outsourced decryption is formulated to transfer a data from
source to destination.
 There are two keys such as private and public key are evolved. And the
combination of the keys generates the message that has to transfer from
one end to other.
 The attributes of the data as well as the master secret key are analyzed by
the proxies so as to generate a private key.
 The attributes of the data as well as the master key are encrypted directly
by access structure attribute so as to generate a public key.
 The encrypted message has to decrypt and the decrypted information
should checked with the original data in order to ensure the originality
after the encryption/decryption process.
 Hence the combination of private key with parameter attributes
generates transform and retrieve key.
 Where transform key generates partial cipher key that has to passed to
the retrieve key so as to generated the original message.
 The main drawback over the existing system is that there is no proper
verification with the proxies. And the attributes considered to frame the
message are not unique in case of common parametric data.

5. System Requirements
 Hardware Requirements:
System : Pentium IV and above.
Hard Disk : 40 GB or Above.
Monitor : VGA and High resolution monitor
Mouse : Logitech.
Ram : 1 GB or Above
 Software Requirements:
Operating system : Windows VISTA or Above.
Front End : Microsoft Visual Studio 2010
(.NetFramework 4.0)
Coding Language : C#
Backend : SQL Server 2008 R2

6. Architecture Diagram