Category Archives: OAuth

Mutual TLS and Proof-of-Possession Tokens: Summary

This is the last part of my PoP and Mutual TLS post series. Part 1 covered some history and motivation, and part 2 looked at various server setups. Part 3 was supposed to be a walk-through guide on how to … Continue reading

Posted in ASP.NET Core, IdentityServer, OAuth, OpenID Connect | 2 Comments

Mutual TLS and Proof-of-Possession Access Tokens – Part 1: Setup

2020 is the year where I want proof-of-possession tokens to become reality. Mutual TLS seems to be the only feasible way to do that today. So here’s another post about it…. This is a two-part post. In this post we … Continue reading

Posted in ASP.NET Core, IdentityServer, OAuth, OpenID Connect | 5 Comments

Hardening OpenID Connect/OAuth Authorize Requests (and Responses)

One of the biggest strengths of OIDC and OAuth is the usage of the browser front-channel. The browser can show a UI and follow redirects, this makes it very powerful and flexible. Guess what – the biggest weakness of OIDC … Continue reading

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Hardening Refresh Tokens

Refresh tokens provide a UX friendly way to give a client long-lived access to resources without having to involve the user after the initial authentication & token request. This makes them also a high-value target for attackers, because they typically … Continue reading

Posted in IdentityServer, OAuth, Uncategorized | Leave a comment

OAuth 2.0: The long Road to Proof-of-Possession Access Tokens

I did a lot of WS-Security in my (distant) past – and whenever we started looking into migrating to OAuth 2.0, there was this one thing on the security check-list that was missing in the OAuth world: proof of possession … Continue reading

Posted in IdentityServer, OAuth | 1 Comment

Use explicit typing for your JWTs

JWTs are being used in many places these days – identity tokens, access tokens, security events, logout tokens… You actually have to be careful when validating a JWT that you don’t mistakenly confuse it with a JWT that was issued … Continue reading

Posted in IdentityServer, OAuth | 2 Comments

Two is the magic Number

..and not 3. To build authentication systems for modern applications, all you need to understand are two OpenID Connect / OAuth 2.0 flow. That’s it. Client Credentials Flow This is probably the simplest flow and it is designed for server … Continue reading

Posted in ASP.NET Core, IdentityServer, OAuth, OpenID Connect | Leave a comment