Middleware Support for Tunable Encryption

To achieve an appropriate tradeoff between security and performance for wireless applications, a tunable and differential treatment of security is required. In this paper, we present a tunable encryption service designed as a middleware that is based on a selective encryption paradigm. The core component of the middleware provides block-based selective encryption. Although the selection of which data to encrypt is made by the sending application and is typically content-dependent, the representation used by the core component is application and content-independent. This frees the selective decryption module at the receiver from the need for application or content-specific knowledge. The sending application specifies the data to encrypt either directly or through a set of highlevel application interfaces. A prototype implementation of the middleware is described along with an initial performance evaluation. The experimental results demonstrate that the generic middleware service offers a high degree of security adaptiveness at a low cost.