Turing is from Mars, Shannon is from Venus: computer science and computer engineering

When thinking about systems, it´s tempting to only envision computational elements such as machines, operating systems, and programming languages, or human elements such as user interfaces, business practices, and public policy. However, to mangle an analogy from physics, the observer is also part of the system. When reasoning about or designing (or breaking into) secure systems, it´s important to remember the tools, mindset, and background we bring to the table. Computer security´s primary background fields are computer science and computer engineering (although some might make a case for mathematical logic). These fields sometimes bring very different approaches to the same basic security problems. We take a light-hearted look at these differences.