Formalization of Ethereum Virtual Machine in Lem

This repository contains

• a Keccak-256 implementation in Isabelle/HOL KEC.thy (to be ported to Lem)
• a RLP implementation (in progress) RLP.thy
• an EVM implementation in Lem lem/evm.lem
• a form of functional correctness defined in Lem lem/evmNonExec.lem
• a relational semantics that captures the callee's nondeterministic behavior RelationalSem.thy
• some example verified contracts in example
• a parser that parses hex code and emits an Isabelle/HOL expression representing the program parser/hexparser.rb

When you see \<Rightarrow> in the source, try using the Isabelle2016-1 interface. There you see ⇒ instead.

Lem?

Lem is a language that can be translated into Coq, Isabelle/HOL, HOL4, OCaml, HTML and LaTeX.

Prerequisites

• Isabelle2016-1
• lem
• OCaml 4.02.3
• opam 1.2.2
• yojson: use opam install yojson
• bignum: use opam install bignum
• easy-format: use opam install easy-format

How to read the proofs

First translate the Lem definitions into Isabelle/HOL:

$ make lem-thy

Then, use Isabelle2016-1 to open ./examples/AlwaysFail.thy. The prerequisite Isabelle/HOL files are automatically opened.

How to run VM tests

Make sure the tests submodule is cloned

$ git submodule init tests
$ git submodule update tests

Extract the OCaml definitions

$ make lem-ocaml

And move to tester directory.

$ cd tester
$ sh compile.sh
$ ./runVmTest.native

Makefile goals

• make deed produces a verified PDF document for the Deed contract in output/document.pdf.
• make doc produces output/document.pdf as well as lem/*.pdf.
• make lem-thy compiles the Lem sources into Isabelle/HOL
• make lem-pdf compiles some of the Lem sources into PDF through LaTeX
• make all-isabelle checks all Isabelle/HOL sources (but not the ones compiled from Lem)
• make does everything above

Links

• For a bigger picture, see overview of Yoichi's formal verification efforts on smart contracts
• For updates, visit a gitter channel