This is with regards to the new Payments apps platform. I represent a payment provider who is currently in the process of integrating with this new payments platform.
My query is on the hmac authentication process. In the verification section (OAuth based - https://shopify.dev/apps/auth/oauth#verification), the following sample is given:-
Is the 'secret' key's value the same as the 'API secret key' assigned to us?
Yes, that would be correct, they are one and the same - same one as seen here in the App Partner Dashboard(docs), which is a secret shared between Shopify and the app.