October 7th, 2007

Polygons

When I am not posting to my livejournal, I often think about odd mathematical problems. Such as, For any polygon with more than 4 sides, is it possible to draw a rectangle inside it such that each vertex touches an edge of the polygon, and no two vertices are on the same edge?

False Channel Labeling

I was watching the cartoon network with my nephew, and it was all live action. I mean if it were labeled the kids network I could see that, but it is the CARTOON network. And yes I am really reaching for posting topics today.

Password Protection

First read this article: http://www.codinghorror.com/blog/archives/000949.html
Then this one: http://www.matasano.com/log/958/enough-with-the-rainbow-tables-what-you-need-to-know-about-secure-password-schemes/

It seems that a simple and easy protection against rainbow tables is to use a random salt per user stored in clear text. I was wondering if instead of a single salt you could use a selection of hash functions. Instead of storing the salt you store the set of hash functions you used in the order you used them. It seems as if this would surely defeat the attack from the Rainbow table. The only downside is that you have to have several good hash functions, which is not trivial.