Peijie Li (TU Delft), Huanhuan Chen (TU Delft), Evangelia Anna Markatou (TU Delft), Kaitai Liang (TU Delft)
Searchable Encryption (SE) has shown a lot of promise towards enabling secure and efficient queries over encrypted data. In order to achieve this efficiency, SE inevitably leaks some information, and a big open question is how dangerous this leakage is. While prior reconstruction attacks have demonstrated effectiveness in one-dimensional range query settings, extending them to high-dimensional datasets remains challenging. Existing methods either demand excessive query information (e.g., an attacker that has observed all possible responses) or produce low-quality reconstructions in sparse databases. In this work, we present REMIN, a new leakage-abuse attack against SE schemes in multi-dimensional settings, exploiting access and search pattern leakage from range queries. REMIN leverages unsupervised representation learning to transform query co-occurrence frequencies into geometric signals, enabling an attacker to infer relative spatial relationships among encrypted records. This approach allows accurate and scalable reconstruction of high-dimensional datasets under minimal leakage. Furthermore, we introduce REMIN-P, an active variant of the attack that incorporates a practical poisoning strategy. By injecting a small number of auxiliary anchor points, REMIN-P significantly improves reconstruction quality, particularly in sparse or boundary regions of the data space. We evaluate our attacks extensively on both synthetic and real-world datasets. Compared to state-of-the-art reconstruction attacks, our reconstruction attack achieves up to $50%$ reduction in mean squared error (MSE), all while maintaining fast and scalable runtime. Our poisoning attack can further reduce MSE by an additional $50%$ on average, depending on the poisoning strategy.