File

mod_http_oauth2: Advertise the currently supported id_token signing algorithm This field is REQUIRED. The algorithm RS256 MUST be included, but isn't because we don't implement it, as that would require implementing a pile of additional cryptography and JWT stuff. Instead the id_token is signed using the client secret, which allows verification by the client, since it's a shared secret per OpenID Connect Core 1.0 § 10.1 under Symmetric Signatures. OpenID Connect Discovery 1.0 has a lot of REQUIRED and MUST clauses that are not supported here, but that's okay because this is served from the RFC 8414 OAuth 2.0 Authorization Server Metadata .well-known endpoint!

---
labels:
- 'Type-S2SAuth'
---

Introduction
============

[PKIX over Secure HTTP (POSH)][rfc7711] describes a method of
securely delegating a domain to a hosting provider, without that hosting
provider needing keys and certificates covering the hosted domain.

# Validating

This module performs POSH validation of other servers. It is *not*
needed to delegate your own domain.

# Delegation

You can generate the JSON delegation file from a certificate by running
`prosodyctl mod_s2s_auth_posh /path/to/example.crt`. This file needs to
be served at `https://example.com/.well-known/posh/xmpp-server.json`.