Better German communications security required radio silence

How could Germany have improved signal security enough to make the war harder for the Allies?

Transmit much less, separate traffic types, use secure landlines where possible, remove repeated text, and report only essential operational information.

Germany needed radio silence wherever possible rather than a succession of new ciphers. Weather traffic should use separate systems, while garrison forces should prefer landlines when circumstances allow. Operational messages should contain only necessary information and omit predictable repeated phrases that help cryptanalysts. The governing rule is to assume the enemy is always listening, although compromised land networks could create intelligence risks of their own.