Comment by throw0101a | Hacker News Reader

Comment by throw0101a | Hacker News Reader

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SRP was good for its time, but things have moved forward in the password-authenticated key exchange (PAKE) world. See for example OPAQUE:

> Currently, the most widely deployed (PKI-free) aPAKE is SRP [RFC2945], which is vulnerable to pre-computation attacks, lacks a proof of security, and is less efficient relative to OPAQUE. Moreover, SRP requires a ring as it mixes addition and multiplication operations, and thus does not work over plain elliptic curves. OPAQUE is therefore a suitable replacement for applications that use SRP.

> This draft complies with the requirements for PAKE protocols set forth in [RFC8125].

* https://tools.ietf.org/html/draft-irtf-cfrg-opaque

More on PAKE generally:

* https://blog.cryptographyengineering.com/2018/10/19/lets-tal...

* https://news.ycombinator.com/item?id=18259393

If you're looking for a challenge-response system for your application, then it's hard to go wrong with SCRAM (which Postgres went with a while ago):

* https://en.wikipedia.org/wiki/Salted_Challenge_Response_Auth...

I have been checking out OPAQUE for sometime. But I couldn't find any reliable javascript implementation that I can use in my webapp. Do you know of any such implementations.

There's no need to use PAKE in a web app.

There are two scenarios in your "webapp". In both scenarios your connection a client should be secured with TLS (HTTPS)

1. Humans, should be authenticated with WebAuthn. This means now they can't get phished (a major threat today), their credentials can't be stolen (even from you, you only have a worthless public key and an arbitrary identifier), their privacy is protected as best possible, and most likely their platform is also looking out for them (e.g. on an iPhone the fingerprint sensor so their kid sister can't even authenticate to your webapp from their phone)

2. Machines should be authenticated with either public key encryption (mutually authenticated TLS) if you're up to it or random revokable tokens issued by your service for that purpose to a human end user.

PAKEs are most valuable when you do not have a secure connection, but a webapp should have a secure connection over HTTPS already.

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