In this paper we revisit the connection between parametricity and noninterference. Our primary contribution is a proof of noninterference for a polyvariant variation of the Dependency Core Calculus of in the Calculus of Constructions. The proof is modular: it leverages parametricity for the Calculus of Constructions and the encoding of data abstraction using existential types. This perspective gives rise to simple and understandable proofs of noninterference from parametricity. All our contributions have been mechanised in the Agda proof assistant
