I found that to be a pretty nice writeup, a little more accessible for the curious layman than a pair of blog entries I wrote on RSA (http://cautery.blogspot.com/2012/06/rsa-encryption-and-other...) and Elgamal (http://cautery.blogspot.com/2012/07/encryption-part-2-elgama...)

Encryption topics were the big wake-up call for me regarding not relying on Wikipedia for math/tech info. When I started the above blog posts, I dug around for background info from a variety of sources until I got my head around the math, and found Wikipedia's entries on encryption topics to be basically unfixable without doing a large enough rewrite to guarantee an immediate revert.

Anyway, I wish this rosedu post had come a few months earlier; it would have saved me quite a wild goose chase.