IPEQ: Querying Multi-attribute Records with Inner Product Encryption

We introduce a secure query processing employing a function hiding inner product encryption (FHIPE) to enable queries on encrypted data that achieve minimal leakage, low latency, and space efficiency. Performing DB operations on encrypted data requires specialized encryption schemes that carefully balance security and performance. For example, fully homomorphic encryption (FHE) is a technique that allows querying an encrypted DB, but FHE ciphertexts are large and can overwhelm machine memory. Querying under FHIPE shows the DB server whether an encrypted record and an encrypted query condition are matched or not using the inner product. However, the query condition and record representation must be carefully considered to ensure that correct results are returned. In this paper, we propose a novel encrypted querying scheme IPEQ with FHIPE. IPEQ can correctly perform multi-attribute Equality, GROUP BY, and JOIN over encrypted data by employing a special encoding to the query condition and record. Our solution also outperforms homomorphically encrypted DB in terms of query execution latency and DB size.