I'm no crypto expert, but I'm guessing nobody had previously cracked it because they hadn't really tried. By today's standards at least, it seems relatively straighforward.<p>I love how obviously human-generated the key is: "13, 34, 57, 65, 22, 78, 49." - the differences between the two digits are almost all 0, 1 or 2. As a species, we must really resent random numbers.