The story starts with a man at his computer programming job, in a deep depression a few months after his best friend died of AIDS. He eventually goes to see a psychologist and takes leave, then takes a "horizontal promotion" to a documentation-writing position. He walks out of work one night, and there's his friend Liam, apparently "undead of AIDS".
The guy, who's name I forgot, assumes he's hallucinating but goes along with it. Liam, totally in shape (and not dying of AIDS), tells him the story about his adventure to the hospital. The government designed a virus (medical) and injected it into Liam. It had a 1% chance of surviving a proper immune system, but since Liam was dying of AIDS, it took off. The virus, in some sci-fi way, read "code" from a microchip on his neck and executed that code in his body. Rebuild his muscles, accelerate his metabolism and immune system. Kill his AIDS, etc, etc. He stole the SDK and booked it out of the hospital, and continued to write algorithms to make him pretty much the strongest man on the planet.
Meanwhile, he passes his cigarette to the main character after "accidentally" wetting the filter, and "infects" him with the virus. He gives his friend a copy of the SDK, and they go to Fry's Electronics to build a new chip for him.
Skip forward, the FBI has both of them. Insert cryptography plug about how 4096-byte encryption cannot be broken, and then they're sent to Africa to shut up.
EDIT -
The cryptography plug was that their houses were both searched and all that they found were a few CD's, all encrypted with pass-poems.
