Errata: March 1, 2019Replace the following sentence in the next to the last paragraph
But you can also use Ajax technology,
which lets you push content to the client.
with the following:
When using web technologies you could use WebSockets instead of messaging, or even resort to pulling, using Ajax to simulate the effect.
In the first line, private should be public.
...identity provider's public key...
In the fourth paragraph, Identify should be Identity.
In the fifth paragraph, sever should be server.