Support OAuth 2.0 Pushed Authorization Requests (RFC 9126)

[tronghn]

RFC 9126 - OAuth 2.0 Pushed Authorization Requests

[PAR] allows clients to push the payload of an OAuth 2.0 authorization request to the authorization server via a direct request and provides them with a request URI that is used as reference to the data in a subsequent call to the authorization endpoint.
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PAR fosters OAuth security by providing clients a simple means for a confidential and integrity-protected authorization request.

This is essentially a server-side POST to an endpoint (e.g. /par) with all the request parameters that would traditionally be included in the /authorize redirect that is returned to a user agent to follow. A security advantage here is that any such parameters are no longer leaked/visible in the end-users browser and available for manipulation.

ID-porten is among the providers that support this extension.