Multi-keyword public key searchable encryption scheme with pattern hiding

To address the limitations of existing multi-user searchable encryption (SE) schemes that fail to hide access patterns, search patterns, and resist keyword guessing attacks, a novel public-key searchable encryption scheme was proposed supporting multi-user and multi-keyword searches. Multi-writer/multi-reader functionality was enabled in distributed systems and employed three key techniques: the secure bit decomposition (SBD) protocol, efficient privacy-preserving outsourced calculation framework with multiple key (EPOM), and randomly introducing false positives to achieve access pattern and search pattern hiding. Each user was allowed to encrypt/upload data and search all authorized encrypted data by the multi-writer/multi-reader capability. The search processing through parallel search across multiple servers was accelerated while maintaining only one encrypted index for all readers. Theoretical analysis and experimental results demonstrate that the proposed scheme satisfies the indistinguishability of trapdoors and ciphertext, supports multi-type Boolean searches, preserves search and access pattern privacy, and achieves execution efficiency comparable to state-of-the-art public-key SE schemes.