“Deployment of these oracles require provisioning of the system (master attestation keys and device identification keys), and establishing a strategy to supervise they correct initial installation (to make sure they are measuring what we want them to measure). Trust on the long term is guaranteed by anti-tampering features and private keys’ protection through a Secure Element.
By design, this approach is neither trustless nor fully decentralized. In the case of the car’s smart contract insurance example, the tracker must have the proper attestation keys (therefore bought from specific vendors) and an audit strategy must be put in place to randomly verify their proper installation (therefore requiring some external trusted parties/auditors).
However, as most of the Hardware Oracles’ use cases require some sort of centralization or authority, this design is a perfect match.”
Read full article here: https://blog.ledger.co/hardware-oracles-bridging-the-real-world-to-the-blockchain-ca97c2fc3e6c