Does anyone know what minimum level of "homomorphism" is necessary to insulate the entity doing surveillance or analytics from legal action?

I ask this about the following contexts:

- government surveillance: does using a homomorphism remove the need for a search warrant?

- in-app analytics: does using homomorphisms allow a firm to consider data not disclaimed by the firm's privacy policy?

- research: when does a homomorphism eliminate the need for IRB approval?