Echidna is a next-generation Ethereum smart contract fuzzer built the by security solutions company - Trail of Bits. As an evaluation tool, Echidna is known for its unique ‘property-based fuzzing’ which tries to falsify user-defined invariants (properties) instead of looking for crashes like a traditional fuzzer. Echidna comes with a multitude of tools to write custom analyses for complex contracts. Targeted toward EVM bytecode, Echidna uses cryptic compile to test contracts.