Infrastructure Design Considerations When Using Client Certificates

This paper will investigate some of the considerations that should be evaluated when looking to bring a new technology into the design of an application. The security technology that will be used as an example is client-based certificates. It is easy to see that there are increasing requirements for web-based applications to use the Internet for conducting private business. This will sometimes require two-way authentication between the client and the server in addition to the more frequently addressed issues of integrity and privacy that certificate use has provided. As with any design, there are several ways to accomplish a given task, with each one providing unique advantages and disadvantages that must be weighed against the criteria of the implementation goals. These points will be discussed and summarized to assist the reader in understanding the trade-offs associated with each approach. Security has become far too broad a subject to cover all aspects that should be raised within a single document. This paper is from the viewpoint of the infrastructure designer and not that of the internals of the application. The paper will be general in nature and will try to emphasize some of the challenges that the security and infrastructure architect may expect to encounter.