Encryption and HUGE numbers
Banks, Facebook, Twitter and Google use epic numbers - based on prime factors - to keep our Internet secrets. This is RSA public-key encryption.
Gold Vault: https://youtu.be/CTtf5s2HFkA
This video features Dr James Grime (http://singingbanana.com/).
Message from James: "Thanks to Dr Chris Hughes of the University of York who showed me how to find the RSA public key from my browser, and showed me how awesome they look when you print them out."
Regarding the keys used for encryption:
x, y prime
Encode key E shares no factors with (x-1)(y-1)
Decode key is D with E*D - 1 a multiple of (x-1)(y-1)
Thanks to Drew Mokris for the animation: http://www.spinnerdisc.com/