Patent ID: 10769295

Abstract:
Embodiments allow join operations to be performed upon encrypted database tables stored on an unsecure server (e.g., as part of a DBaaS offering), with reduced information leakage. Such secure join operations may be implemented through the combination of two cryptographic techniques: non-deterministic (randomized) searchable encryption; and attribute based encryption. The searchable encryption (e.g., Symmetric Searchable Encryption: SSE) allows join values to be revealed only for rows fulfilling additional predicate attributes that the client has filtered for, thereby offering fine granular security. The attribute based encryption (e.g., Key-Policy Attribute-Based Encryption: KP-ABE) avoids the unmanageable consumption of memory that would otherwise result from the creation of intermediate constructions on the server. Embodiments offer a solution reducing information leakage of join values not contained in the result of the actual database query. This results in fine granular security because join values of data rows not involved in the join computation, remain semantically secure.