Privacy-Preserving Keyword Search With Access Control for Secret Sharing-Based Data Outsourcing

Searchable encryption, also known as secure search, is a technology that enables search operations on encrypted data while maintaining its confidentiality. Extensive research has been conducted on searchable encryption utilizing public-key and symmetric encryptions. However, public-key encryption involves significant computational expenses and is deemed inefficient for querying large databases, particularly in cloud settings. Hence, our attention is on searchable encryption using a secret sharing scheme (also known as searchable secret sharing), which is recognized for its minimal computational complexity. A secret sharing scheme is a method to transform a secret input into several distinct values known as shares. Kamal et al. introduced a simple searchable encryption utilizing secret sharing schemes, yet did not include user access control capabilities. In this study, we introduce a secure search method with user access control employing a secure computation based on a (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k, n</i>) threshold secret sharing scheme, where every data stored in the cloud has an owner, and owners grant access to users at their discretion.We assume a client-server model to perform a secure computation between the owner, the player, and the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> ≥ <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> cloud servers. Furthermore, we provide an in-depth analysis of the security aspects of our proposed distribution, query generation, and search processes, demonstrating that our approach is resilient against an honest-but-curious adversary with information from up to <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i>−1 computing servers. Moreover, we also include an improved and efficient method by using a (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n, n</i>) additive secret sharing scheme when assuming <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> = <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> computing servers. We provide discussion comparing both our proposed methods in terms of their computation and communication costs. Finally, we also include a detailed performance analysis using Python, including a comparison with conventional secret sharing-based methods.