A data owner outsourcing the database of a multi user application wants to prevent information leaks caused by outside attackers exploiting software vulnerabilities or by curious personnel. Query processing over encrypted data solves this problem for a single user, but provides only limited functionality in the face of access restrictions for multiple users and keys. ENKI is a system for securely executing queries over sensitive, access restricted data on an outsourced database. It introduces an encryption based access control model and techniques for query execution over encrypted, access restricted data on the database with only a few cases requiring computations on the client. A prototype of ENKI supports all queries seen in three real world use cases and executes queries from TPC-C benchmark with a modest overhead compared to the single user mode.

Recent databases are implemented as in-memory column-stores. Adjustable encryption offers a solution to encrypted database processing in the cloud. We show that the two technologies play well together by providing an analysis and prototype results that demonstrate the impact of mechanisms at the database side (dictionaries and their compression) and cryptographic mechanisms at the adjustable encryption side (order-preserving, homomorphic, deterministic and probabilistic encryption).

Modern enterprise systems have to comply to regulations such as Basel III resulting in complex security requirements. These requirements need to be modeled at design-time and enforced at runtime. Moreover, modern enterprise systems are often business-process driven, i.e., the system behavior is described as high-level business processes that are executed by a business process execution engine.

Public key cryptography based on elliptic curves is a promising foundation for energy-scarving pairwise key establishment in wireless sensor networks. Focusing on the Diffie-Hellman key-agreement, identity-based schemes can be applied to provide mechanisms for authentication. The AQ-protocol presented by Arazi et al. introduces such a key establishment supporting fixed as well as ephemeral keys.