Illegal prime numbers

Back in the old days, when there were DVDs (some of my readers might be too young to remember), there was a copy protection algorithm called "CSS" (Content Scramble System). Naturally, people found ways to circumvent it, and one of the first programs to do that was called "DeCSS". There were several lawsuits against the authors of that software, and a legislative effort to stop the distribution of that software.

In response, there were several clever ideas to distribute descriptions of the DeCSS program, including Haikus, dramatic readings, and in 2001, mathematicion Phil Carmody found a prime number which, when written in hexadecimal, forms a .gzip file containing the program. At the time, it was one of the largest known prime numbers, worth publishing for that fact alone.