Instantaneous Proxy-Based Key Update for CP-ABE
Attribute Based Encryption (ABE) scheme has been proposed to implement cryptographic fine grained access control to shared information. It allows to achieve information sharing of type one-to-many users, without considering the number of users and their identities. However, original ABE systems suffer from the non-efficiency of their attribute/key revocation mechanisms. Based on Ciphertext-Policy ABE (CP-ABE) scheme, we pro- pose an efficient proxy-based immediate private key update which does require neither re-encrypting cipher-texts, nor affect other users’ secret keys. The semi-trusted proxy, we have introduced, assists nodes during the decryption process without having ability to decrypt nodes’ data. Moreover, the proxy eliminates the 1- effects-n phenomenon from which suffer existing solutions when it comes to revoke nodes attributes. Finally, we analyze the security of our scheme and demonstrate that the proposed solution outperforms existing ones in terms of generated overheard.
CP-ABE; Access Control; Pairing Cryptogra- phy; Attribute revocation;