Introduction
What?
Asymmetric encryption is one of the most important advances in cryptographic security ever made. It underpins all security on the Web, in Wi-Fi connections, and in secure email and other communication of all kinds. RSA is a pretty good place to start.
Why?
It is ubiquitous, but it is also subtle and easy to implement or use incorrectly, and a lack of correctness means a sometimes drastic reduction in security.