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Why do you feel there's a flaw? The «root» key signs the batch keypair. It's a normal certificate chain.
by infofarmer 6y ago
Why do you feel there's a flaw? The «root» key signs the batch keypair. It's a normal certificate chain.
- dandanua 6y agoAccording to this [1], keypairs are generated randomly on a registration request. To sign such keypairs root private key must be somewhere on the device. But I don't see a mention of this in the docs. [1] https://developers.yubico.com/U2F/Protocol_details/Key_generation.html https://developers.yubico.com/U2F/Protocol_details/Key_gener...
- infofarmer 6y agoThere's a separate attestation keypair that is static, is either unique per device or unique per 1k-100k batch of devices and signed by a manufacturer key. There's no need to keep a "root private key" on device. https://developers.yubico.com/U2F/Attestation_and_Metadata/ https://developers.yubico.com/U2F/Attestation_and_Metadata/ https://fidoalliance.org/fido-technotes-the-truth-about-attestation/ https://fidoalliance.org/fido-technotes-the-truth-about-atte...
- dandanua 6y agoThanks, the second link explains it quite clearly. It's indeed a safe and logical scheme of device verification.