M-EDESE: Multi-Domain, Easily Deployable, and Efficiently Searchable Encryption.

Searchable encryption is an essential component of cryptography, which allows users to search for keywords and retrieve records from an encrypted database at cloud storage while ensuring the confidentiality of users' queries. While most existing research on searchable encryption focuses on the single domain setting, we propose the first Multi-Domain, Easily-Deployable, Efficiently-Searchable Encryption (M-EDESE) system that allows users to query keywords cross domains with high efficiency and preserved privacy without additional cooperation from the cloud storage. In the multi-domain setting, a user who belongs to a domain can query keywords from another domain under an inter-domain partnership. Any party can participate in the M-EDESE system as a domain without global coordination other than agreeing on an initial set of global reference parameters. Each domain maintains a set of users and acts as an individual multiple-user searchable encryption system while maintaining its own database. M-EDESE enables easy deployment without any requirement for cloud storage setup, thus it is compatible with the existing cloud storage platform. In addition, the M-EDESE system facilitates instant user revocation within each domain and instant partner revocation across domains. We provide a concrete construction of M-EDESE and security proofs on query privacy, unforgeability, and revocability. We also conduct a rigorous experimental evaluation of the performance of M-EDESE in a real-world setting, showing that M-EDESE is highly efficient for querying an open-sourced database.