I've been revising the principles, and came up with this. It's an early version. As ever, corrections and suggestions are welcome. Calling them Laws is perhaps a bit overreaching - but on reflection I thought that's mostly what they are, break them and the system won't be secure. I will put the Laws up on the 'net shortly, hopefully with a link for suggestions and comments. The Laws of secure information systems design: Law 0: It's all about who is in control Law 1: Someone else is after your data Law 2: If it isn't stored it can't be stolen Law 3: Only those you trust can betray you Law 4: Attack methods are many, varied, ever-changing and eternal Law 5: The entire system is subject to attack Law 6: A more complex system has more places to attack Law 7: Holes for good guys are holes for bad guys too Law 8: Kerckhoffs's Principle rulez! - usually... Law 9: A system which is hard to use will be abused or unused law 10: Design for future threats Law 11: Security is a Boolean Law 12: People offering the impossible are lying Law 13: Nothing ever really goes away Law 15: "Schneier's law c" [1] holds illimitable dominion over all... including these laws -- Peter Fairbrother [1] " a: Anyone, from the most clueless amateur to the best cryptographer, can create an algorithm that he himself can't break. It's not even hard. b: What is hard is creating an algorithm that no one else can break, even after years of analysis. c: And the only way to prove that is to subject the algorithm to years of analysis by the best cryptographers around."