Generally Hybrid Proxy Re-Encryption And Its Application

In recent years, a lot of enterprises provide data sharing service based on cloud storage, but security issues on data sharing about these services have not been solved perfectly, proxy re-encryption(PRE) has become an outstanding solution idea to deal with those problems. From the perspective of the type of PRE schemes, there are identity based PRE, attribute based PRE and certificateless PRE and so on. From the perspective of the feature of PRE schemes, there are conditional PRE, broadcast PRE and anonymous PRE and so on. Due to the different scenarios between different cryptography clouds storage systems, they deploy different proxy re-encryption schemes according to the requirement of data sharing. Because of the heterogeneity between different schemes, sharing data between these heterogeneous cryptography clouds has become a serious problem.Generally Hybrid Proxy Re-Encryption(GHPRE) solved the problem that sharing data between heterogeneous cryptography clouds based on the general definitions of Public Key Encryption(PKE) and Proxy Re-Encryption using the method of temporary public and private key, and provide a general framework to construct hybrid PRE scheme, the method of temporary public and private key is that sender request a temporary identity for receiver, and then the proxy of sender sends re-encrypted ciphertext and the ciphertext of temporary key to receiver. Compared with the existing HPRE, GHPRE has better generality and ease of use. Generality is that GHPRE is applicable to data sharing between many types of proxy re-encryption. Ease of use is that adding functionality to existing systems without reprocess existing data is enough when deploy GHPRE into the running cloud.Under the standard model, if the PRE scheme of receiver is IND-CPA security and the PRE scheme of sender is IND-S-CPA security, then GHPRE is IND-S-CPA secure. An instantiation of GHPRE is accomplished after the GHPRE; it transforms the ciphertext from identity based proxy re-encryption to ElGamal and verifies the validity of GHPRE. Finally, we show an application of GHPRE to heterogeneous cryptographic cloud storage.