Comment by cm2187 | Hacker News Reader

Comment by cm2187 | Hacker News Reader

I am unfortunately not bullish that this will pick up but there are strong arguments for this way to authenticate.

- you would typically store the private key on a disk-encrypted app-whitelisted iphone, so that the computer you are browsing with, whether yours or a public machine, is never involved in the authentication. Effectively this achieves 2FA. And you don't care if the machine you browse with is compromised.

- this does not rely on a third party, it is purely an authentication mechanism. So it removes the risk of that third party tracking you, selling or leaking your data.

- it should be fairly practical and easy to use, does not rely on installing anything on the machine you browse with

- the website you authenticate to can be hacked, it stores no useful information that can be used by another domain

I am not sure Gibson has the audience in the sillicon valley required for this to become mainstream. But the principle makes a lot of sense to me. Of course your are still exposed to the password protecting your private key being stolen, which gives the attacker access to everything, but this is no different from a password manager. Except that unlike a password manager, you do not need to enter that master password on the machine you are browsing with, which considerably reduces the risk.

There's a slight problem. It doesn't 'effectively' achieve 2FA at all. If I lose my phone and lose my master key, I lose my all my identities, and even if I somehow remember them, I can't prove they are mine.

    HMAC(Master key + Domain)             -> private key + identity (public key)
    HMAC(Master key + Domain) + challenge -> response

Lose that master key, and you can't get anywhere. By contrast, FIDO U2F works loosely like this:

    1. first factor
    2. HMAC(Master key + Domain) + challenge -> response

Key point being that it's still 2FA, where SQRL is still just one factor. If you lose your FIDO device, at least as it stands, most sites make you have a token generator app as well, or at least a path through customer support.

It may help to think of an email + password as being two factors, and various 2FA solutions actually being three factors. Email is something you can prove independently of your password. SQRL has exactly one factor, and zero failover strategy.

It's debatable whether it should be possible to get through customer support after losing anything, but the 99% of online security infrastructure that builds a chain of trust upon your email address really does work for most people in most cases. It's terrible that email addresses are easily correlated across different websites, but the reality is that any replacement identity solution needs to be as easily restored in case of failure.

For SQRL to work and give you an out for lost master keys, it would need at least a way of creating a redundancy, like replacing HMAC(Master key + Domain) with an asymmetric negotiation of the correct identity, or adding another layer of indirection that makes the master key replaceable.

Depends on how you define two factor. To me it is using a different device than the device you authenticate with and unless you compromise that device you cannot authenticate any other way.

The way it deals with compromised private keys is that you can store the list of websites you authenticated to on a central location and run a reset of all your authentications on all websites in one go from there. But then it relies on a third party.

I don't pretend that this is the ultimate solution (nor am I aware that there is an ultimate solution) but it does seem more secure and practical than anything else I have seen so far. I am sure you can make more secure but less practical and of course less secure and more practical.

2FA requires 2 authentication factors like a password & a token i.e. your PIN and banking card. It doesn't really have anything to do with where you enter those. https://en.wikipedia.org/wiki/Multi-factor_authentication

There are nice ways to store private keys; including BIP39 that creates a 24 word mnemonic phrase that you can write down somewhere. (Not that that's perfect security, but it is nice)

The lost master key problem is addressed here: https://www.grc.com/sqrl/idlock.htm

Nice summary, a couple of minor corrections. * SQRL is not a 2FA, it's a better 1st factor

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