A Question about REST API and Unauthenticated Users

As we start to look at transitioning from iMIS 20.2 2015 to iMIS 20.2 2017 and then hopefully to the Cloud in the future, we are trying to figure out how we can do REST API request that the general public would perform searches for individuals for example, their certification information. I see that in iMIS 20.2 2017, we are required to have a bearer token and that requires logging in, but what if the user does not have a login and we need to enable searches?

What we used to do with iBO.NET to handle these requests is to create a custom User object that implements the Asi.iBO.IiMISUser interface and then pass that along to the iBO.Net to handle those requests, but I don't see a way to do that in the REST APIs.

My question is how do we transition this functionality for this type of situation or is there a better way?