Where magic lives: Analysis of HSBC Vulnerability
http://da.vidnicholson.com/2006/08/analysis-of-hsbc-vulnerability.html
Very nice article... simple, easy to read and understand.
Most crypt-analyses is very mathematical in nature, and I can hardly understand the individual words in it, let alone whole sentences :-(
As a result, I've always had trouble explaining to people how proper analysis can break a system, because to the untrained mind, even XOR would seem unbreakable!
For me, therefore, the real value of this article is that I can probably use it to give ordinary people exactly such an insight.