You have a requirement to limit search results in your Azure Cognitive Search based on the user groups. That way only the users who are authorized to access the documents should be able to view them. You applied the equality expressions to achieve the objective. However, the expressions have become tedious to maintain and hence you want to apply a simpler and faster approach of security filtering to meet the requirements. Review the steps below and choose three steps that you will choose to accomplish security filtering 

Answer options:

A.Create a field that contains the principal identifiers
B.Create customer managed keys & store them in key vault
C.Update existing documents with principal identifiers
D.Issue a search request with search.in filter
E.Create a service principal in Azure Active Directory

Correct Answers: A, C and D
Option A is correct because this field is used to specify which groups have access to the documents. The field is made filterable and the search results are filtered based on the user access.
Option B is incorrect because customer managed keys are not relevant for this use case. They are used in the context of blob storage where data encryption uses customer-provided keys for data encryption.
Option C is correct because you would need to add or update the group ids in the JSON documents using the POST method.
Option D is correct because to limit the access to the groups, you have to specify the filter.
Option E is incorrect because creating a service principal in the scenario is not relevant. The requirement is met through a filter on the documents based on user groups.
Reference:
To learn more about Security in Cognitive Search, use the link given below: 

https://docs.microsoft.com/en-us/azure/search/search-security-trimming-for-azure-search