SoK: Searchable Encryption with Differential Privacy

In this Systematization of Knowledge paper, the intersection of Differential Privacy and Searchable Encryption is examined. Although each technique address distinct aspects of information security, with Differential Privacy obscuring individual-level details and Searchable Encryption enabling secure queries over encrypted data, recent research that combine these approaches show that more robust privacy guarantees can be had without compromising utility. Firstly, we lay out the theoretical underpinnings of Differential Privacy and Searchable Encryption, illustrating how noise addition and cryptographic primitives can be aligned. We propose a taxonomy that characterizes existing integrations along dimensions of efficiency, scalability, utility, and security trade-offs. With a thorough survey of existing literature, we identify methods that reconcile noise-injected schemes with indexed and encrypted data, while demonstrating the various trade-offs for query latency, storage overhead, and overall system complexity. Finally we discuss open problems and proposed next steps, justified by the current state of existing research. Our findings illustrate the practicality and challenges of combining Differential Privacy with Searchable Encryption, providing a foundation for future innovation in this field.