You could do worse than to confuse the meanings of "code" and "cipher"—even cryptographers sometime use the terms as though they had the same meaning. There is, however, a definite distinction between ...

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 ...

In Part I, you broke a simple cipher. Now try creating a more complex cipher. Cut out the NOVA Decoder Ring and NOVA Cipher Code Ring and the window marked INDEX. You are now going to put this simple ...

The National Security Agency can easily defeat the world’s most widely used cellphone encryption, a capability that means the agency can decode most of the billions of calls and texts that travel over ...