I suspect most of my readers can just about remember light speed, the 100 foot barn, and the 110 foot log from learning about relativity. The barn had doors at each end, and one set would close the instant the other doors opened. The challenge was to transport the log through the barn. The answer had to do with light speed and collapsing space, so that as one got close enough to light speed, the log shortened, and it could fit through the barn. It was a simple enough calculation as to how fast one could go to make the log shrink how much. When each of us had completed the math, the professor sprang the surprise on us: "OK, what is happening from the perspective of a cockroach on the log?"
System Architecture
Parsimony and Security
I have been thinking about security and parsimony lately. Security is not merely about confidentiality or even identity. It is about predictability and integrity. Challenges to predictability and integrity occur not only malefactors, but from those who develop, test, and maintain systems. Even interoperability is a part of security, introducing new sub-systems, or upgrading old ones, can introduce unanticipated interactions and failures.
Cybersecurity for smart buildings and the smart grid
Building systems have until now been secured only for interaction between their parts. Schemes such as shared tokens used on open networks serve the purpose of isolating systems from interaction. They do not address the more intriguing security issues of interaction with non-system actors. These non-system actors may be agents from other systems, business process from other companies, or even direct consumer access.
Today’s shared token security schemes are only thinly deployed...