How to create aspects in ktor and uniformly process parameters

[Heizi1]

I use Ktor version 2.3.13.
I want to implement an aspect feature that can modify the parameter content when the request enters and can obtain and modify the response content before returning the response.
For example, there is an encrypted username in my request parameters, and I want to handle it uniformly. Before getting the parameters in routing, I want to decrypt these encrypted usernames and assign them. How should I do it?

[Stexxe]

Have you tried writing a plugin to implement handling of every incoming request and outgoing response?