This blog is about SharePoint Provider Hosted Add-in Trust Types. It provides the details for kind of trust types to be used while deploying the SharePoint Provider Hosted Add-in on different hosting environment.
About SharePoint Provider Hosted Add-in
Microsoft has officially renamed the SharePoint provider hosted App as SharePoint Provided Hosted Add-in. The provider hosted add-in can be installed on SharePoint on your on-premise server or on SharePoint's online platform. The key business logic component however is deployed outside the SharePoint environment which provides us the flexibility to opt for any programming language. The SharePoint hosted app has to be designed with client side programming framework. It is important to note here that server side coding is not allowed in SharePoint hosted app.
In SharePoint provider hosted Add-in you have option to host it with your required hardware choice. You can ask your IT department to host the add-in on dedicated server of any third party hosting service. Azure is a good option for hosting the add-in. The provider hosted app can also use the SharePoint standard stuff for any business requirement but the SharePoint standard stuff will run on SharePoint environment.
Courtesy: Microsoft Docs
The provider hosted add-in will use OAuth or JSOM to communicate with standard SharePoint components. The Microsoft Azure Access Control Service (ACS) is playing trust broker role when this SharePoint provided hosted add-in is hosted on Azure and installed on O365. If the add-in is installed in SharePoint on your on-premise server then it needs server certificate along with ACS to enable high trust between add-in and SharePoint.
Trust Types Details
This table illustrates the kind of trust required in SharePoint Provider Hosted Add-in and SharePoint according to its various deployment and installation places.
SPO - SharePoint Online
ACS - Azure Access Control Service
My objective here is to update the tech community about latest changes by Microsoft about the naming convention of the SharePoint Provider Hosted Add-in. This blog also lists the various kinds of trust type for SharePoint Provider Hosted Add-in, which need to be used in certain deployment scenarios. This knowledge should be absorbed before taking on related work.