When is it permissible to transmit messages encoded to obscure their meaning?

The FCC generally prohibits the use of codes or ciphers intended to obscure the meaning of a transmission. Amateur radio is meant to be an open and transparent service, meaning anyone tuning in should be able to understand the communication. There is, however, a crucial exception for safety and security: telecommand. You are allowed to use encryption when transmitting control commands to space stations (like satellites) or model craft (like drones). This prevents unauthorized people from hijacking control of these crafts, which could cause damage or safety hazards.