NetCrypt: A Transparent Secure Communication Service

In this paper we describe the architecture and performance characteristics of a transparent, secure communication service developed for the Linux operating system. We address two key issues: performance and distributed key management. In distributed systems, conventional cryptography provides good performance at the cost of unacceptable key distribution overhead, while public key cryptography provides scalable key distribution but suuers from poor performance. We present a hybrid solution which uses public key cryptography for key management and conventional cryptography for fast block encryption. Detailed discussions of the system design, operation, and protocols are given. Finally, we present the results of our performance testing, and analyze to what extent we attained our stated goals.