Authenticated Identity-Based Encryption Scheme with Equality Test for Cloud-Based Social Network

Enabling registered users to match friends with the same interest, location, etc. is the most fundamental service provided by social network. With expanding openness of social network, the amount of data is growing exponentially. Cloud computing is then introduced into social network to mitigate the issue of storing and analyzing a substantial amount of data. How to realize user matching while protecting users' privacy remains a key challenge in cloud-based social network. As a cryptography tool, identity-based encryption with equality test (IBEET) can be used to match users with the same interest, location, etc. without decrypting the corresponding ciphertexts, therefore, it can well meet the key challenge in cloud-based social network. In this article, we propose an authenticated identity-based encryption with equality test (A-IBEET) scheme based on the observation that the cloud server may recover users' private information from the ciphertexts through offline message recovery attack (OMRA). Our scheme provides stronger security guarantee for social network users by resisting against OMRA in single-server setting. It could better protect users' privacy without sacrificing efficiency compared with related works.