Description

You are in a room with 100 people and want to accomplish two things.;;First, to send messages in secret to an individual on the opposite side whom you have never met or previously corresponded.;;There is no privacy; every communication is transmitted to everyone in the room.;;Second thing; you have information you wish to keep completely secret,;but still be able to convince your neighbour that you possess this information.;;Is it possible to succeed in either or both of these endeavours?;;Of course it is! Hundreds of millions of such transactions take place every day - internet bank transfers and secure online purchasing in the case of the first and ATM machines in the second.;;The question is, how? The answer is, very, very clever mathematics.;But is it deep and intractable? Well no, the most important of the ideas needed date from the 4th century BC to the early 17th century; all long before calculus. High school stuff.;;In four, one hour lectures we will be able to show the key ideas and to actually implement both of the above. The background requirements are the student should be curious and to like puzzles; no real mathematical sophistication is needed, but solid algebra skills are essential. No text is needed; a full set of web pages will be constructed with relevant material. The benefit is to understand the basics of electronic commerce and the challenges posed by this.;;One way to state this is by the following question:;;When you make a purchase online does your bank know what item you are buying, and does the seller get your credit card information?;;If you answered "yes" to either of these then this class will enlighten you.