Every day we use our computers to perform remarkable feats. A simple web search picks out a
handful of relevant needles from the world's biggest haystack. Uploading a photo to Facebook
transmits millions of pieces of information over numerous error-prone network links yet
somehow a perfect copy of the photo arrives intact. Without even knowing it we use public-key
cryptography to transmit secret information like credit card numbers and we use digital
signatures to verify the identity of the websites we visit. How do our computers perform these
tasks with such ease? John MacCormick answers this question in language anyone can understand
using vivid examples to explain the fundamental tricks behind nine computer algorithms that
power our PCs tablets and smartphones.
