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Comment by blamestross | Hacker News Reader

How do you keep people from simulating a fido key? There is intrinsically no way to detect if the hardware signature was actually done by hardware.

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FIDO has a device attestation https://developers.yubico.com/U2F/Attestation_and_Metadata/ But their scheme indeed looks like flawed.

There is a way to make it correct, though. Device manufacturer also has to inject its own root private key into the device. So the device will use additional, third signature on behalf of manufacturer.

Then the root private key gets extracted, because there's lots of money to be had from doing so

If you are the manufacturer, who already know the root private key and can make some fake users, you still won't be able to print new money from nowhere. Yes, you CAN make double spending, but this will just split the network, because every participant will accept only one spend, not both.

Who and how issues the new money? how do you decentralize that? Otherwise you have a central bank and a database is more efficient.

That’s a problem that has already been solved in various ways by existing cryptocurrencies. For example, NANO was premined and then distributed via a faucet that required solving CAPTCHAs. Other cryptos just award holders more coins, or use other solutions.

That is Yubico's flavor of U2F attestation. U2F has been succeeded by WebAuthn, you'll probably want to look at https://www.w3.org/TR/webauthn-2/#sctn-defined-attestation-f... instead.

Why do you feel there's a flaw? The «root» key signs the batch keypair. It's a normal certificate chain.

According 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_gener...

There'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://fidoalliance.org/fido-technotes-the-truth-about-atte...

Thanks, the second link explains it quite clearly. It's indeed a safe and logical scheme of device verification.

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