Section 2.3, due on September 13

Since we hadn't been assigned reading over the weekend before, I neglected to check the assignment site to see that this had been assigned. Really I had read this section earlier because I found it interesting. I'm going to blog about it despite the fact that I missed credit, just for completeness.

Difficult: When I first read this section, I found the cyphertext attack method difficult to understand. It seemed that they were only succeeding because they already knew the length of the key word. After the class discussion, I now understand how the frequency counts were used to good effect, showing how to find the length of the key word.

Reflective: I was fascinated by this cypher. It seems that it should be easily possible to modify this method so that the cypher is not so easily breakable. Possibly just giving messages in short pieces would be enough. My partner and I actually tried this as the code for our project, changing the shift cypher part to an affine cypher instead, and adding some more rules. I realize now that, should Eva know our method, then ours is only slightly harder than Vigenere's, since affine cyphers are only slightly harder than shift cyphers, but since then I've had some new ideas I'd like to see how to break based on this cypher. Maybe I'll write them up and attach them to this blog, if I have time later.