Verifying Outsourced Decryption of CP-ABE with Signature

Attribute-based encryption enables users to encrypt and decrypt messages based on user attributes. The computational complexities of decryption are very high. By Outsourcing decryption to the third party, it can address the problem. But the verifiability of results returned from the third party has yet to be addressed. In this paper, we introduce short signature and give a new model of verifiable outsourced decryption of ABE cipertexts. By using signature, we achieve the verification and provide good performance and propose a concrete scheme. We prove that our scheme is both secure and verifiable. Moreover, we show an implementation of our scheme and result of performance measurements.