NOVA scienceNOW's "Can Science Stop Crime" introduced you to Tadayoshi Kohno, a University of Washington computer scientist who's made it his mission to take over networked machines, identifying ...

You can make a message secret in countless different ways. One common way is to use a substitution cipher, in which one letter is substituted for another. Another is to employ a transposition cipher, ...

Hannah handed me a piece of paper with the following string of letters. “Each letter stands for another one,” said Hannah. “Ooh, a substitution cipher!” I thought. But I was stumped. “Is this just one ...

The concluding words of Unsolved! are a call to action. Craig Bauer, a US mathematician and editor-in-chief of the journal Cryptologia, ends his hefty history of cryptography by noting that even as he ...