«Drumbeats» by Kevin J.Anderson, Neil Peart

When the six-year-old daughter of a billionaire nanotech magnate is kidnapped, ueber-consultant Jonathan Knox and counterterrorism agent Marianna Bonaventure must team up with an experimental artificial intelligence to rescue her, never suspecting the little girl is the key to a plot that could destroy the NSA’s most advanced cryptanalysis capability — and go on to kill every man, woman, and child in the United States.