Cloud computing has increasingly popular among clients and business around the world. Although cryptographic schemes can give data protection to clients in public cloud, a few issues likewise remain problematic, for example, secure data group information and fine-grained access control of time-sensitive data. In this project, we propose an identity-based data group sharing and dissemination scheme in public cloud, in which data proprietor could broadcast encrypted data to a group of receivers at one time by determining these recipients identities in a convenient and secure way.
With a specific end goal to accomplish secure and flexible data group dissemination, we receive attribute-based and timed-release conditional proxy re-encryption to ensure that only data disseminators whose attributes satisfy the access approach of encoded information can disperse it to different groups after the discharging time by assigning a re-encryption key to a cloud server. The re-encryption conditions are related with attributes and releasing time, which enables information proprietor to implement fine-grained and time release access control over disseminated ciphertexts. The theoretical analysis and experimental results demonstrate our proposed scheme makes a tradeoff between computational overhead and expressive dissemination conditions.