Minos:Bringing Accountability and Traceability to Attribute-Based Keyword Search

The rapid adoption of cloud computing has intensified concerns over data privacy, particularly in the context of outsourced datasets. Attribute-Based Keyword Search (ABKS) has emerged as a promising cryptographic solution for enabling secure and efficient search over encrypted data. However, most existing ABKS schemes typically assume that all clients behave honestly, which weakens their applicability in real-world scenarios. In this work, we challenge this assumption by introducing ABKSUT, a new framework that incorporates user accountability and traceable ownership into ABKS. We formalize ABKSUT and present a concrete instantiation, Minos, which properly embeds the user's identity in the trapdoor and the data owner's identity in the ciphertext, enabling secure search, fine-grained access control, and post-hoc accountability. We formally prove the security and correctness of Minos and evaluate its performance using real-world datasets. Results show that Minos achieves strong security guarantees with practical efficiency, making it suitable for real-world deployment.