The fourth passage of the Kryptos sculpture has been unsolved for over 21 years. If you are one of the professional cryptanalysists and amateur enthusiasts who have attempted to solve this puzzle, you may be wondering if Kryptos passage 4 (K4) can be solved by a double key Vigenere cipher. The answer seems to be no. Kryptos cipher 4 is not a Vigenere cipher.I'll walk through how I attempted to brute force the keys for…
You slept in and missed the Senate Intel Committee hearing on worldwide threats. No problem, I'll give you a rundown.The top 5 threats to the US right now are China, Russia, Iran, North Korea, and terrorism. Haines, the ODNI director, broke it down:China: competition in the cyber, space, and geographic spaces. A "near peer". They have their own demographic challenges.Russia: interested in asymmetric conflict (cyberrrrr) with the goal of weakening the USIran: regionally crucial, Iraq…
Information leakage happens when a system helps an adversary achieve some goal. We can understand leakage through quantitative information flow (QIF), a robust framework that gives ways to quantify the amount of leakage of a system. In this post, we will walk through how we can statically model a system as a channel matrix. We'll also see how a channel maps a prior probability distribution to a hyper-distribution that helps an adversary narrow down the…
Here I introduce an introductory overview of quantitative information flow (QIF), a mathematical framework used to precisely discuss leakage. We start with a system that takes some sensitive information as input, processes it, and produces some publicly observable output. We want to determine how the system affected the sensitive information. This overview will focus on the often relevant and intuitive measure of Bayes vulnerability, which addresses when the adversary must guess the value of the…
I've put together a few of my favorite resources on cryptography. My general recommendation is to watch lecture videos. Academic papers and textbooks can be quite dense, but authors clear things up in their PowerPoint presentations and videos. I've included links to some of my favorite talks but I also list some courses and textbooks. These resources are about the math and theory behind cryptography and don't address implementation. Fundamental Cryptography Here are some resources on…