Refinement types for secure implementations

Jesper Bengtson (1) , Karthikeyan Bhargavan (2) , Cédric Fournet (2) , Andrew D. Gordon (3) , Sergio Maffeis (4)

1 ITU - IT University of Copenhagen
2 Microsoft - Microsoft Research [Cambridge]
3 UPF - Universitat Pompeu Fabra [Barcelona]
4 Department of Computing [London]

We present the design and implementation of a typechecker for verifying security properties of the source code of cryptographic protocols and access control mechanisms. The underlying type theory is a λ-calculus equipped with refinement types for expressing pre- and post-conditions within first- order logic. We derive formal cryptographic primitives and represent active adversaries within the type theory. Well-typed programs enjoy assertion-based security properties, with respect to a realistic threat model including key compromise. The implementation amounts to an enhanced typechecker for the general purpose functional language F#; typechecking generates verification conditions that are passed to an SMT solver. We describe a series of checked examples. This is the first tool to verify authentication properties of cryptographic protocols by typechecking their source code.

Domaines: Cryptographie et sécurité [cs.CR]; Informatique et langage [cs.CL]

Jesper Bengtson, Karthikeyan Bhargavan, Cédric Fournet, Andrew D. Gordon, Sergio Maffeis. Refinement types for secure implementations. ACM Transactions on Programming Languages and Systems (TOPLAS), 2011, 33 (2), ⟨10.1145/1890028.1890031⟩. ⟨hal-01294973⟩