The panel criticizes Germany's repeated habit of transmitting at high power and frequency in both world wars. Encryption can protect the contents of a message, but it cannot hide the fact that a transmitter is active, its approximate location, or changes in the pattern of communications. Analysts can combine those patterns into a picture of deployments and operations. The mistake is especially striking because German forces also practiced traffic analysis against Allied communications and therefore understood the method's value.
Notable Point · 53:24-54:21
Why secure codes do not defeat signals traffic analysis
An enemy can learn where forces are and how they are organized from radio activity even without reading the encrypted messages.