ou 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 two. Codes are letter combinations or symbols used to represent words or concepts. A "10-4" heard over a police radio means "affirmative," for example; and three dots, three dashes, and three dots (...---...) in Morse code stands for the distress message "SOS."