On a RAV4 Prime (or RAV4 PHEV for those outside of North America), these ECUs reportedly have "ECU Security Key" (A SecOC implementation) or signed/authenticated CAN bus commands since replacing them requires a check in with a Toyota server to "Update ECU Security Key" :
ECM
Hybrid vehicle control ECU
Forward recognition camera
No. 2 skid control ECU (brake actuator assembly)
Rack and pinion power steering gear assembly
Clearance warning ECU assembly
Steering sensor
Central gateway ECU (network gateway ECU)
Combination meter assembly
Airbag sensor assembly
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There's nothing about smart key in here specifically. Not sure on later "ECU Security Key" vehicles though. If someone were to look up replacement instructions for the Smart Key ECU on Toyota's TechInfo, and if it has ECU Security Key update as a step or not, that could answer this.
SecOC is based on symmetric key cryptography. If an ECU is replaced and has a new key, this key will have to be taught to all other ECU's in the vehicle communicating with it.
ECM
Hybrid vehicle control ECU
Forward recognition camera
No. 2 skid control ECU (brake actuator assembly)
Rack and pinion power steering gear assembly
Clearance warning ECU assembly
Steering sensor
Central gateway ECU (network gateway ECU)
Combination meter assembly
Airbag sensor assembly
---
There's nothing about smart key in here specifically. Not sure on later "ECU Security Key" vehicles though. If someone were to look up replacement instructions for the Smart Key ECU on Toyota's TechInfo, and if it has ECU Security Key update as a step or not, that could answer this.