This sounds like an interesting system, but I think you are arguing for a system that as-of-now is only theoretical and is very different against the current crop of JavaScript-powered client-side-hashing methods which I am arguing against.

The first implementation was Bellovin and Merritt's Encrypted Key Exchange in 1992. In 2000 a provably secure implementation was released. PAKE has been around for quite some time and is proven, and is in wide use in the field. Here's a decent article on the subject: https://blog.cryptographyengineering.com/2018/10/19/lets-tal...

I don't dispute the technology exists - I dispute that this technology can be deployed on a web app to general users effectively. I don't believe that is currently possible in production effectively in a way that neutralizes my arguments that an attacker could just change the JavaScript to record passwords somewhere.

That's why the browser's built-in login Form could be so useful, it would have its own security context, so I, as a user can be sure that no Javascript could read that

I would happily sign up and reuse a password for a website that I didn't trust if it were as secure as described (PAKE + browser built-in login)

I'm really not sure what you are disputing here. PAKEs are for preventing man in the middle attacks, not for securing a local program or preventing malicious code from running in the browser. No one is advocating, use a PAKE and all your problems are gone - it's about addressing key exchange over the wire and eliminating an entire class of attack. Password managers are a tough subject - they are like coffee . Yes, there may be small amounts of toxic stuff in it, but that is offset by a factor of 10,000 by the number of people who do not get in a wreck on the way to work, thanks to being awake and aware form 70mg of caffeine.

PAKE isn't theoretical at all and the post you're responding to didn't say client side hashing it said zero knowledge proofs.

PAKE is theoretical from a web-development perspective because there is no secure way for me to implement PAKE in my web app for a user to log in with in 2022. It doesn't exist - you tell me how to implement PAKE login right now.

Zero Knowledge Proofs would be awesome (something like WebAuthn/FIDO right now?) but I am arguing more in general against client-side hashing methods that are currently usable, mainly JavaScript-based ones.

Not sure what you mean.

1. There is, of course, a way to implement it in your web app. I don't know what you mean by "no secure way" ?

> I am arguing more in general against client-side hashing methods that are currently usable, mainly JavaScript-based ones.

Even a trivially implemented client side hashing approach protects against a number of attacks.

I meant, let's say I picked a framework. Django, Laravel, Express, similar.

How would I implement PAKE login for my users? How would I get every user to log in with PAKE? How would I ensure that my code for PAKE could not be overwritten if a hacker took over part of my server?

It doesn't exist, AFAIK, on a user-facing front at this time in a secure way that a hacker couldn't just change the logic for.

Implementing opaque isn't overly hard. You can find pseudocode, implementations, state machine diagrams, etc, online. Here's a good post that links to implemented code: https://blog.cloudflare.com/opaque-oblivious-passwords/

I know nothing of framework support, I don't use frameworks. I'm likely going to contribute some open source code in the near future from my company to simplify things though.

But you could also just have your client do:

    salt = sha256("your company name goes here" + username)
    password_hash = pbkdf2(plaintext_password, salt)

and get some nice benefits.

> How would I ensure that my code for PAKE could not be overwritten if a hacker took over part of my server?

Depends on the server and the level of control. But it'll help in a number of cases. You're assuming the attacker has full control over the web-page's contents (among other things - even if an attacker had the web page's contents CORS means they couldn't send http only cookies to an attacker controlled server), which is a very specific, powerful position to be in.

What benefits would you get though?

You are still exposing the password_hash to the server and any compromise there (software or hardware, as described in your link) would still let an attacker grab password_hash, craft a custom client, and send it as if the original client had hashed the plaintext_password to begin with.

The attacker doesn't need to know plaintext_password, just the string you use to authenticate with in order to replay it. The password_hash becomes the new password.

Then due to the salt being on the client, it still opens the password up to rainbow table attacks etc.

If the attacker only has access to the hash that hash is only usable for your website. If the user uses the same password for another site an attacker can not log into that other site using the hash.

That's really the main benefit of this approach - it reduces the impact of password reuse.

If I’m understanding your argument correctly (I may not be) - implementing PAKE would only be helpful in a scenario where an attacker gets access to hashed passwords, but isn’t able to modify front-end code to directly intercept unhashed passwords, right?

You are correct. I (and I think most people?) consider that to be the most common attacker scenario.

Gotcha - and I can definitely see the utility with a large userbase.

From a corporate perspective, with a segmented + well-firewalled architecture, and a lot of surface area for injection vulns, I totally agree with you. The article was priming me to think of a flat, single-box solodev environment, where if someone breaks in, they own everything - which is why I think the original post above us mentioning PAKE is getting a lot of questioning.

PAKE isn’t about preventing compromise at the serving of the front end. That’s still the responsibility of the server maintainer. PAKE is about reducing damage potential. The responsibility of keeping your servers secure applies regardless of use of PAKE. PAKE just makes it possible that if your database is leaked in some smash-and-grab someone can’t just run a rainbow table against it to suss out passwords against emails.

Not theoretical, you can do it today.

https://www.npmjs.com/package/libopaque

Metamask basically works this way and is used on thousands of apps.