Contributory Broadcast Encryption With Efficient Encryption And Short Cipher Texts

ABSTRACT

Traditional broadcast encryption (BE) schemes allow a sender to securely broadcast to any subset of members but require a trusted party to distribute decryption keys. Group key agreement (GKA) protocols enable a group of members to negotiate a common encryption key via open networks so that only the group members can decrypt the cipher texts encrypted under the shared encryption key, but a sender cannot exclude any particular member from decrypting the cipher texts. In this paper, we bridge these two notions with a hybrid primitive referred to as contributory broadcast encryption (ConBE). In this new primitive, a group of members negotiate a common public encryption key while each member holds a decryption key. A sender seeing the public group encryption key can limit the decryption to a subset of members of his choice. Following this model, we propose a ConBE scheme with short ciphertexts. The scheme is proven to be fully collusion-resistant under the decision n-Bilinear Diffie-Hellman Exponentiation (BDHE) assumption in the standard model. Of independent interest, we present a new BE scheme that is aggregatable. The aggregatability property is shown to be useful to construct advanced protocols.

AIM

The aim of this paper is a group of members negotiate a common public encryption key while each member holds a decryption key. A sender seeing the public group encryption key can limit the decryption to a subset of members of his choice.

SCOPE:

The Scope of this Paper  is proven to be fully collusion-resistant under the decision n-Bilinear Diffie-Hellman Exponentiation (BDHE) assumption in the standard model.

EXISTING SYSTEM

BE schemes in the literature can be classified into two categories, i.e., symmetric-key BE  and public-key BE . In the symmetric-key setting, only the trusted center generates all the secret keys and broadcasts messages to users. Hence, only the key generation center can be the broadcaster or the sender. Similarly to the GKA setting, tree-based key structures were independently proposed to improve efficiency in symmetric-key BE systems and further improved in with O(log n) keys. Cheon et al.presented an efficient symmetric BE scheme allowing new members to join the protocol anytime. Harn and Lin proposed a group key transfer protocol. Their protocol is based on secret sharing and is considerably efficient, albeit it cannot revoke (compromised) users

 DISADVANTAGES

1. Group key agreement (GKA) protocols enable a group of members to negotiate a common encryption key via open networks so that only the group members can decrypt the cipher texts encrypted under the shared encryption key but a sender cannot exclude any particular member from decrypting the cipher texts.
2.   A  BE system heavily relies on a fully trusted key server who generates secret decryption keys for the members and can read all the communications to any members.

PROPOSED SYSTEM

In this paper, construct an efficient ConBE scheme with our AggBE scheme as a building block. The ConBE construction is proven to be semi-adaptively secure under the decision BDHE assumption in the standard model. Only one round is required to establish the public group encryption key and set up the ConBE system. After the system set-up, the storage cost of both the sender and the group members is O(n), where n is the number of group members participating in the setup stage. However, the online complexity (which dominates the practicality of a ConBE scheme) is very low. We also illustrate a trade-off between the set-up complexity and the online performance. After a trade-off, the variant has O(n2=3) complexity in communication, computation and storage. This is comparable to up-to-date regular BE schemes which have O(n1=2) complexity in the same performance metrics, but our scheme does not require a trusted key dealer. We conduct a series of experiments and the experimental results validate the practicality of our scheme.

ADVANTAGES

1. In ConBE, anyone can send secret messages to any subset of the group members, and the system does not require a trusted key server.
2. As a versatile cryptographic primitive, our novel ConBE notion opens a new avenue to establish secure broadcast channels and can be expected to secure numerous emerging distributed computation applications.

SYSTEM CONFIGURATION

HARDWARE REQUIREMENTS:-

·                Processor          -   Pentium –III

·                Speed                -    1.1 Ghz

·                RAM                 -    256 MB(min)

·                Hard Disk         -   20 GB

·                Floppy Drive    -    1.44 MB

·                Key Board         -    Standard Windows Keyboard

·                Mouse               -    Two or Three Button Mouse

·                Monitor             -    SVGA

SOFTWARE REQUIREMENTS:-

·                Operating System       : Windows  7                                    

·                Front End                  : JSP AND SERVLET

·                Database                  : MYSQL

·                Tool                           :NETBEANS

 

REFERENCE

Wu, Q. Qin, B.  Zhang, L. Domingo-Ferrer, J.“Contributory Broadcast Encryption With Efficient Encryption And Short Cipher Texts,” IEEE Transactions on Computers, Volume PP Issue 99, APRIL 2015.