Secure Server Key Management Designs for the Public Cloud

Abstract

The Enterprise Level Security (ELS) model focuses on designing secure, distributed web-based systems starting from basic principles. One area of ELS that poses significant design challenges is protection of web server private keys in a public cloud. Web server private keys are of critical importance because they control who can act as the server to represent the enterprise. This includes responding to requests as well as making requests within the enterprise and to its partners. The cloud provider is not part of this trusted network of servers, so the cloud provider should not have access to server private keys. However, current cloud systems are designed to allow cloud providers free access to server private keys. This paper proposes design solutions to securely manage private keys in a public cloud. An examination of commonly used approaches demonstrates the ease with which cloud providers can currently control server private keys. Two designs are proposed to prevent cloud provider access to keys, and their implementation issues are discussed.