[valiant-comma]

Just a nitpick. Matthew Green uses the analogy of signing keys being leaked often as evidence that Ozzi’s proposed system would be similarly not secure. This is a weak analogy: signing private keys are often leaked because their use case requires them to be “online” in some fashion (code must be signed with the private key so it can be verified with the public key). Similarly, CAs must use private keys operationally (to sign customer CSRs), increasing the risk of key compromise.

In Ozzi’s proposal, the private key never actually has to exist outside the environment it was created in, only the public key does. As pointed out in other comments, LE would not need access to the private key, either, they could simply submit the encrypted passcode to the manufacturer, who would then decrypt it on their behalf using the private key.

[allenz]

Code signing and decryption both require access to the private key, possibly through a hardware security module. I don't see why decryption has less exposure.