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 ...

We use ciphers to keep secrets secret. To crack ciphers, you need math, psychology and a slab of luck. It's not easy. Many great ciphers remain unsolved, as cryptologist Craig P. Bauer tells DW's ...