Simple pictures to explain DRY and SRP

The Single Responsibility Principle (SRP) and Don’t Repeat Yourself (DRY) are two common principles of good software engineering.  This article is probably a statement of the bleeding obvious, but I was struck by how the two principles could be illustrated by simple variations on one simple diagram.  I couldn’t remember seeing such diagrams before and … Continue reading Simple pictures to explain DRY and SRP

Authentication, authorisation and the chain of trust

I recently walked by my old college.  There was a sign outside: Closed to visitors.  I realised that two cards in my wallet would get me in, which made me think of some security concepts: the difference between authentication and authorisation, and the chain of trust.  I’ll go into those a bit in this article, … Continue reading Authentication, authorisation and the chain of trust