Cryptography as a Network Service

Cryptography is a powerful tool for building secure dis-tributed systems, albeit at substantial computational cost. This is especially true for public key cryptography. Con-ventional wisdom dictates that cryptography must be done locally in order to be secure. We argue for an approach in which public key cryptographic operations are provided as a network service. This service operates over long-lived associations secured by symmetric cryptography. This network architecture amortizes the cost of special-purpose cryptographic hardware across many users. We describe the implementation of such a system, and perfor-mance results we obtained. 1