I have my doubts whether the current UWB standard is really secure by design, for that the hardware has to be able to encrypt a bit of challenge and return it with negligible delay (which is why I suggest a precomputed code to XOR a challenge with). As soon as the stack has large delays, replay becomes possible again ... and the
CCC stack seems huge and full of delays.
Otherwise this wouldn't make sense :
"15CCC DIGITAL KEY
‘Ranging keys’ are derived from CCC Digital
Key authentication handshake and securely
stored in the secure element. When in use,
ranging keys have a limited 12-hour lifetime to
shorten the time window for an attacker."