A secure ranging system can use a secure processing system to deliver one or more ranging keys to a ranging radio on a device, and the ranging radio can derive locally at the system ranging codes based on the ranging keys. A deterministic random number generator can derive the ranging codes using the ranging key and one or more session parameters, and each device (e.g. a cellular telephone and another device) can independently derive the ranging codes and derive them contemporaneously with their use in ranging operations.