“At one of the final IETF meetings before AH and ESP were finalized, someone from Microsoft got up and gave an impassioned speech about how AH was useless given the existence of ESP, cluttered up the spec, and couldn’t be implemented efficiently (because of the MAC in front on the data).

Our impression of what happened next was that everyone in the room looked around at each other and said, “Hmmm. He’s right, and we hate AH also, but if it annoys Microsoft let’s leave it in, since we hate Microsoft more than we hate AH.”

From “Network Security: PRIVATE communication in a PUBLIC world“.

Yesterday I was reading the network security book I talked about before and I found out a funny criptography game, which took me kinda a lot of time to solve. These ciphers are simple substitution ciphers of the type that many people like to amuse themselves trying to solve. Newspapers often publish a daily cryptopuzzle (along the lines of a daily crossword puzzle) which readers try to solve — often during their daily commutes. Anyway, here it is:

Cf lqr’xs xsnyctm n eqxxqgsy iqul qf wdcp eqqh, erl lqrx qgt iqul!

Free cookies to who can solve it! As proof, you must include the md5 of the string “all_caps_solution:all_caps_nick” (double quotes excluded).
For the record, mine is f2ee0b5b3ad916313414e29ce5c578e6

It was a dark and stormy night. Somewhere in the distance a dog howled. A shiny object caught Alice’s eye. A diamond cufflink! Only one person in the household could afford diamond cufflinks!

So it was the butler, after all! Alice had to warn Bob. But how could she get a message to him without alerting the butler? If she phoned Bob, the butler might listen on an extension. If she sent a carrier pigeon out the window with the message taped to its foot, how would Bob know if it was Alice that was sending the message and not Trudy attempting to frame the butler because she spurned her advances?

That’s what this book is about. Not much about character development for Alice and Bob, we’re afraid; nor do we really get to know the butler. But we do discuss how to communicate securely over an insecure medium…

From “Network Security: PRIVATE communication in a PUBLIC world“.