Description

There is a trend for sensitive user data to be stored by third parties on the Internet. Attribute-based encryption (ABE) can be used for log encryption. Instead of encrypting each part of a log with the keys of all recipients, it is possible to encrypt the log only with attributes which match recipient’s attributes. This primitive can also be used for broadcast encryption in order to decrease the number of keys used. As more sensitive data is shared and stored by third-party sites on the Internet, there will be a need to encrypt data stored at these sites. In this project the system proposes generic constructions of CPA-secure and RCCA-secure ABE systems with verifiable outsourced decryption from CPA-secure ABE with outsourced decryption. At a high level, in order to construct such ABE schemes with verifiable outsourced decryption, the system begin with a CPA secure ABE scheme with outsourced decryption. The system also instantiate our CPA-secure construction in the standard model and then show an implementation of this instantiation. In this project the system propose a novel technique to build an ABE with verifiable outsourced decryption (VO-ABE) based on an AB-KEM. The system implement the CP-ABE scheme with verifiable outsourced decryption. The system propose an appropriate transform for the actual secret key to achieve outsourcing the decryption. It provided a feasible method to verify the outsourced decryption and built a concrete ABE scheme with verifiable outsourced decryption. It also makes us obtain generic RCCA-secure construction more naturally. It can be transformed into a selectively RCCA-secure ABE system with verifiable outsourced decryption in the standard model.