Strongly Secure and Cost-Effective Certificateless Proxy Re-encryption Scheme for Data Sharing in Cloud Computing

摘要

Proxy re-encryption (PRE) has been considered as a promising candidate to secure data sharing in public cloud by enabling the cloud to transform the ciphertext to legitimate recipients on behalf of the data owner, and preserving data privacy from semi-trusted cloud. Certificate-less proxy re-encryption (CL-PRE) not only eliminates the heavy public key certificate management in traditional public key infrastructure, but also solves the key escrow problem in the ID-based public key cryptography. By considering that the existing CL-PRE schemes either rely on expensive bilinear pairings or are proven secure under weak security models, we propose a strongly secure CL-PRE scheme without resorting to the bilinear pairing. The security of our scheme is proven to be secure against adaptive chosen ciphertext attack (IND-CCA) under a stronger security model in which the Type I adversary is allowed to replace the public key associated with the challenge identity. Furthermore, the simulation results demonstrate that our scheme is practical for cloud based data sharing in terms of communication overhead and computation cost for data owner, the cloud and data recipient.