Gupta's research interests are in the area of computer systems, in particular, in building systems that provide strong security and privacy properties to users. Examples of systems that he built include: hiding the knowledge of a person's media diet from a Netflix-like media delivery service; hiding user emails from the email service provider while allowing the provider to run important functions (such as spam filtering) over email. A common theme in his research is to take theoretical constructs from the literature (for example, cryptographic protocols) and carefully refine and apply them to provide the desired security and privacy properties. He also strives for practicality, so the systems created are backed by solid implementations and evaluations. For instance, the prototype of his media server served a video library of a few tens of terabytes and ran over a hundred machines on Amazon EC2.