already familiar with such problems in "communications discipline". They hadn't completely solved the problems either, but they had at least managed to get it through the heads of most of their signalmen that if they didn't have time to properly encrypt a message, they shouldn't bother trying; send the message unencrypted, or "in the clear". A partially or badly encrypted message could undermine a cipher or code system, sometimes completely, which made an unencrypted message far preferable. Example Below are pages from a U.S. Army World War I trench code, an edition designated as "Seneca:" References History of cryptography Signals intelligence of World War I