Logical Relations for Formally Verified Authenticated Data Structures by Chaitanya Agarwal

Venue: Bharti501

Abstract: Authenticated data structures (ADSs) allow untrusted third parties to carry out operations which produce proofs that can be used to verify an operation’s output. Such data structures are challenging to develop and implement correctly. In this talk, I will talk about a library, Authentikit, that is implemented in OCaml, that generates authenticated versions of data structures automatically. I will also talk about recent work by us (https://dl.acm.org/doi/abs/10.1145/3719027.3744801) that gives a formal proof of security and correctness of Authentikit. The proof is based on a new relational separation logic for reasoning about programs that use collision-resistant cryptographic hash functions. This logic provides a basis for constructing two semantic models of a type system, which are used to justify how Authentikit makes use of type abstraction to enforce security and correctness. Using these models we also prove the correctness of several optimizations to Authentikit and then show how optimized, hand-written implementations of authenticated data structures can be soundly linked with automatically generated code. All of the results have been mechanized in the Rocq prover using the Iris framework.

Speaker Bio: Chaitanya Agarwal (https://culechetoo.github.io <https://culechetoo.github.io/>) is a 3rd year computer science PhD student at the New York University, advised by Joseph Tassarotti. He is broadly interested in programming languages and formal verification with a particular focus on verification of security applications. In the past, he has also worked with Thomas Wies on abstract-interpretation analysis for recursive, higher-order programs, and with Shibashis Guha, on developing statistical-model-checking techniques for Markov Decision Processes (MDPs). Chaitanya obtained his B.Tech. from IIIT Delhi.