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I mean, I was a engineer that participated in those discussions when I worked at an IDP firm. The concern that if we got popped and the password database was l

I mean, I was a engineer that participated in those discussions when I worked at an IDP firm. The concern that if we got popped and the password database was leaked somehow, that with TOTP the attackers had everything to start logging in as users who had weak passwords but with public/private schemes they didn't. This was a very real concern that affected preference for public/private schemes (which included hardware tokens), and engineering effort to decrease the UX burden of hardware tokens specifically. You might correctly call that concern more focused on CYA of the the firm itself, but I think that's not the worse thing in the world, and the underlying crypto primitives certainly played a role here.

tptacek 5y ago
This doesn't even make sense as an objection. If you get popped, attackers are going to log in with whatever credentials you don't revoke. You're simply going to revoke all your 2FA credentials; retaining them, no matter what scheme was used to store them, would be malpractice. Meanwhile: WebAuthn (nee U2F) was literally introduced as an anti-phishing tool --- not as a database protection technology. They did U2F because people kept getting phished with code-generator authentication. The problem with TOTP is that it doesn't have a mechanism to authenticate the site asking for the code.
- monocasa 5y ago
  Yes, you would revoke them as soon as you realize, but until you realize (and practically there's generally a delta there for a successful attack) in public key schemes of 2FA the attacker doesn't have enough to login as those users since they only have those user's public keys. For TOTP they very well might have everything they need for weak passwords. If you can trend towards public key based schemes there's real benefits from the IDPs prespective. Yes TOTP wasn't designed to help here, but from the IDP's perspective that just means that you should gently shift users to 2FA schemes that do provide those semantics. And U2F/FIFO is not the only other option here, just the only one that can be implemented totally in browser for the client. Duo's phone push notifications are public key crypto under the hood for one example.
  - tptacek 5y ago
    The question is why TOTP has lost favor. The reasons are that it has poor UX, and that it doesn't authenticate sites. That's pretty much it.
    - monocasa 5y ago
      And I'm saying that as a former engineer at an IDP, the shape of the crypto played a major role in the forms of 2FA we favored, causing us to specifically de-emphasize TOTP in favor of public key schemes. The calculus is different if you're just a regular website, but the question was pointed at Google, an IDP in their own with many forms of public key schemes implemented.

tptacek 5y ago

This doesn't even make sense as an objection. If you get popped, attackers are going to log in with whatever credentials you don't revoke. You're simply going to revoke all your 2FA credentials; retaining them, no matter what scheme was used to store them, would be malpractice. Meanwhile: WebAuthn (nee U2F) was literally introduced as an anti-phishing tool --- not as a database protection technology. They did U2F because people kept getting phished with code-generator authentication. The problem with TOTP is that it doesn't have a mechanism to authenticate the site asking for the code.

monocasa 5y ago
Yes, you would revoke them as soon as you realize, but until you realize (and practically there's generally a delta there for a successful attack) in public key schemes of 2FA the attacker doesn't have enough to login as those users since they only have those user's public keys. For TOTP they very well might have everything they need for weak passwords. If you can trend towards public key based schemes there's real benefits from the IDPs prespective. Yes TOTP wasn't designed to help here, but from the IDP's perspective that just means that you should gently shift users to 2FA schemes that do provide those semantics. And U2F/FIFO is not the only other option here, just the only one that can be implemented totally in browser for the client. Duo's phone push notifications are public key crypto under the hood for one example.
- tptacek 5y ago
  The question is why TOTP has lost favor. The reasons are that it has poor UX, and that it doesn't authenticate sites. That's pretty much it.
  - monocasa 5y ago
    And I'm saying that as a former engineer at an IDP, the shape of the crypto played a major role in the forms of 2FA we favored, causing us to specifically de-emphasize TOTP in favor of public key schemes. The calculus is different if you're just a regular website, but the question was pointed at Google, an IDP in their own with many forms of public key schemes implemented.