keVm

KEVM, sometimes stylized keVM, is the formal executable semantics of the Ethereum Virtual Machine implemented in the K framework. It provides a precise, machine-checkable model of EVM execution that can be used for formal analysis and verification of smart contracts. The project is open-source and community-maintained, with contributions from researchers in formal methods and blockchain engineering.

In KEVM, the complete EVM state is modeled: the stack, memory, storage, program counter, gas accounting, and the call semantics for messages, contract creation, and reverts. The model covers the EVM’s gas rules, environmental data, and precompiled contracts, reflecting how operations interact with external calls and internal state. Because the semantics are executable, KEVM supports both concrete execution and symbolic execution using the K framework tooling, enabling rigorous reasoning about possible execution paths.

Applications of KEVM include proving properties about EVM bytecode and Solidity-compiled programs, verifying contract invariants, and generating test cases or counterexamples for contract behavior. Researchers use KEVM to analyze cryptographic routines, to study safety properties, and to compare EVM behavior across versions or implementations.

Limitations arise from the complexity and size of the EVM, which makes the KEVM model large and evolving. This can pose challenges for scaling to very large contracts or extensive verification tasks. KEVM is intended to complement other verification and testing approaches, such as static analysis and fuzzing, and to integrate with the broader K Framework ecosystem for formalizing blockchain protocols.