Building Secure and Reliable Systems

Chapter 4. Design Tradeoffs

By Christoph Kern

with Brian Gustafson, Paul Blankinship, and Felix Gröbert

Security and reliability needs often seem difficult to reconcile with a project’s feature and cost requirements. This chapter covers the importance of reviewing your system’s security and reliability needs as early as possible in the software design phase.

We start by talking about the connection between system constraints and product features, then provide two examples—a payment processing service and a microservices framework—that demonstrate some common security and reliability tradeoffs. We conclude with a discussion about the natural tendency to defer security and reliability work, and how early investment in security and reliability can lead to sustained project velocity.

So you’re going to build a (software) product! You’ll have lots of things to think about in this complex journey from devising high-level plans to deploying code.

Typically, you’ll start out with a rough idea of what the product or service is going to do. This might, for example, take the form of a high-level concept for a game, or a set of high-level business requirements for a cloud-based productivity application. You’ll also develop high-level plans for how the service offering will be funded.

As you delve into the design process and your ideas about the shape of the product become more specific, additional requirements and constraints on the design and implementation of the application tend to emerge. ...