"Telling Secrets Soundly: Modular arithmetic and public key encryption"
featuring Gil Moss

On February 10, 2013, Gil Moss led the first Sunday Math Circle of the semester in a discussion of modular arithmetic and how it applies to public key encryption. To get a handle on modular arithmetic, students began with "clock arithmetic," and practiced dealing with numbers that were equivalent given different clock sizes. Then, students got an idea of public key encryption with a demonstration of how to transmit a secret message publicly using paint mixing. A crucial point here was that paint, while easy to mix, is difficult or impossible to unmix. This led the group to explore a public key encryption algorithm which would allow two people to use a combination of public and private keys to "Tell Secrets Loudly."

Printable version of the flyer

Videos from the talk: Gil Moss, February 10, 2013

Here are some pictures from the talk. Right click and select 'view image' to see it larger.