Science in a minute 
presented by NSF GK12 of the University of Cincinnati. 
Sponsored by AAAS.
Ava: I really like Joshua, but he is always around Lilly.
Ava: How can I possibly tell her without him knowing?
Ava: I guess I could try another language...
Ava: Il est mignon n'est pas?
Lilly: Oui je sais.
Joshua: Tu sais je parle français aussi...
Ava: Do YOU have any ideas?
Narrator: Scramble your message to make it hard to understand.
Ava: I think I've done something like that before...
Narrator: That's the right direction - but you're 
 still stuck if Joshua knows about them.
Try combining one of these with something that only you and Lilly knows.
Ava: Oh like the sum of our birthdays as 
 a starting point for a sliding scale!
Ava: Thanks!
Narrator: The foundations of cryptography are as old a human existence...
we use math, language and now computer theory to help 
 develop new ways of keeping and breaking secrets. 
