A look at password security, Part II: Web Sites
(World News Science)

In part I, we took a look at the design of password authentication systems for old-school multiuser systems. While timesharing is mostly gone, most of us continue to use multiuser systems; we just call them Web sites. In this post, I`ll be covering some of the problems of Web authentication using passwords. As I discussed previously, the strength of passwords depends to a great extent on how fast the attacker can try candidate passwords. The nature of a Web application inherently limits the velocity at which you can try passwords quite a bit. Even ignoring limits on the rate which you can transmit stuff over the network, real systems - at least well managed ones - have all kinds of...