Towards security in sharing data on cloud-based social networks

Nowadays, ubiquitous sensor devices such as mobile phones, laptops, GPSes, etc. allow one to access not only his own data but also others´ on cloud servers. To enhance security, data is usually encrypted before sending to the servers. However, making use of others´ ones encrypted data without decryption keys is very challenging. In this paper, we suggest a framework that allows users of cloud-based social networks to share their private data in a secure manner. In our framework, every user in a group has his own secret key to encrypt and decrypt data. The key will be revoked if the user leaves the group. Using proxy re-encryption schemes, the framework helps any user be able to access others´ data in the same group.