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 ...

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, ...

Seems pretty cryptic, but the puzzle is more simple than it first appears. The numbers follow a simple substitution cipher, a common way to turn a series of letters into a list of numbers. A = 1, B = ...

Encryption is an essential tool for protecting data—but the technology can be a bit confusing. This ebook explains what encryption is, how it works, and why it’s so important. From the ebook: ...