h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Little Brother, by Cory Doctorow.
(and its sequel : Homeland).

Marcus is 17 years old.
He's in high school in San Francisco, and he and his friends are hackers and into role playing.

One day they are out on a scavenger hunt when several bombs go off across the city.
There's panic.
One of them is injured, they try to find help, but they get arrested for not having run to safety / being out on the street when the SWAT teams arrive.

The Department of Homeland Security has taken control of the town, and will remain in charge until the people responsible for the terror attacks are arrested.
Except, they like being in charge.
Martial law, curfew and the enforcement thereof, and repression are things they enjoy.
... As opposed to, say, young smartarses who defy their authority and defend human rights.

This could be classified as a young adult novel, but on the other hand, it's really rather dark and pessimistic in places.
There's torture, there's rebellion, there's guilt.
But it also refers to activism and human rights.
And technology, and online security / safety / secrecy.

Those themes are favourites of Doctorow's, who is also a Creative Commons advocate and against DRM.
Due to this, he has made most - possibly all - of his books (novels, short stories and non fiction) available as free dowloads from his website.

Obviously, if you like what he does, you're more than welcome to play fair and actually buy them too.

*downloads*
with an n.

Doctorow is an interesting fella. I note that he only accidentally has the same last name as one of my favourite novelists.

However, naming his daughter Poesy Emmeline Fibonacci Nautilus may come back to haunt him when she grows up...

Oh I don't know. That's a pretty cool name. But a lot to live up to, I guess...