Cipher Text Policy Based Attribute Encryption
ABSTRACT:In a cipher text policy attribute based encryption system, a user’s private key is associated with a set of attributes (describing the user) and an encrypted cipher text will specify an access policy over attributes. A user will be able to decrypt if and only if his attributes satisfy the cipher text’s policy. With the recent adoption and diffusion of the data sharing paradigm in distributed systems such as online social networks or cloud computing, there have been increasing demands and concerns for distributed data security. One of the most challenging issues in data sharing systems is the enforcement of access policies and the support of policies updates. Cipher text policy attribute-based encryption (CP-ABE) is becoming a promising cryptographic solution to this issue. It enables data owners to define their own access policies over user attributes and enforce the policies on the data to be distributed. However, the advantage comes with a major drawback which is known as a key escrow problem .The key generation center could decrypt any messages addressed to specific users by generating their private keys. This is not suitable for data sharing scenarios where the data owner would like to make their private data only accessible to designated users. In addition, applying CP-ABE in the data sharing system introduces another challenge with regard to the user revocation since the access policies are defined only over the attribute universe.
A.Rohidha, D.Sivaharani, P.Aurchana