Snårkl: Somewhat Practical, Pretty Much Declarative Verifiable Computing in Haskell

Verifiable computing (VC) uses cryptography to delegate computation to untrusted workers. But in most VC schemes, the delegated program must first be arithmetized – expressed as a circuit with multiplication and addition over a finite field. Previous work has compiled subsets of languages like C, LLVM, and bespoke assembly to arithmetic circuits. In this paper, we report on a new DSL for VC, called Sn̊arkl (“Snorkel”), that supports encodings of language features familiar from functional programming such as products, case analysis, and inductive datatypes. We demonstrate that simple constraint-minimization techniques are an effective means of optimizing the resulting encodings, and therefore of generating small circuits.