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Comment by Pxtl | Hacker News Reader

I'm not a security guy, but wouldn't the most seamless approach be to encrypt the key collection with a master password and store the encrypted key collection on the server? So on a new device you'd download the encrypted key collection and then decrypt it locally?

If they forget their password, they can re-upload it from a validated device with a new master password.

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Biggest issue is single point of failure for total access to all devices. Get\guess\beat out the master password and its game over on all connected devices.

The way it works now is with SMS authentication which is not really secure at all.

Where does Keybase use SMS authentication?

Nowhere, IIRC you have to add new device from an already trusted ones. GP probably thought about other messengers.

Not only that but this also enables offline attacking of the password. If you can compromise the Keybase server and grab the encrypted passwords, you can then attack it at your leisure with whatever computing power you can scrounge up, over whatever time duration you want. And when you break it, as long as any of the included devices are still on the account, you'd have complete access to everything.

Requiring existing devices to be actively involved in provisioning a new device prevents all of this.

Ah, that makes more sense.

So in Keybase, what does device to device provisioning look like? "Hey, you've just set up this device - a message has been sent to all your other devices, OK the message and come back here and you'll be good to go"

You just scan a QR code. Or if you want to do an offline device you can type in a a set of words that represent the key.

Yes, but you can use 2-factor auth to control downloading the keystore, so in order to hack the person's account you need to already have physical possession of one of their devices and the master password (either to access their keystore or to get through 2FA).

And if it's not a 2FA device, the victim can use 2FA to push a disavowal of the old keys and set up new keys. That's an ugly and server-centric solution, but "halp I got hacked" is going to be an ugly case no matter what.

Isn’t this pretty close to how Apple iMessage works? I agree it’s a decent compromise to give encryption to the masses, but it has its downsides if Apple is compelled by a government to manipulate that.

All security is compromise though. And I think Apple has done something amazing with what is provided given their install base.

Why store it on a server? You could backup to a sdcard or transfer it between devices with NFC or similar when you move from one to another

The goal is "encryption for the masses" and "the masses" aren't going to put up with "wait, I have to jump through hoops to log in on more than one device?"

Phone-to-phone NFC doesn't seem very hoopy to me if you want to transfer credentials without a middle-man.

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