I have empathy for people who end up stuck in the in-between areas, where out-of-the-box building blocks solve part of their problem, but how to glue them together can still get tricky.
For one example, you've got a shared secret. Can you use it as a secret key? Do you have to feed it through a KDF first? Can you use the same key for both encryption and signing? Do you have to derive separate keys?
For one example, you've got a shared secret. Can you use it as a secret key? Do you have to feed it through a KDF first? Can you use the same key for both encryption and signing? Do you have to derive separate keys?