Proving and verifying execution

WARNING

Soundness of the proof is not yet guaranteed by Stwo, use at your own risk!

WARNING

The prover is not available on Windows. Sorry for your inconvenience.

WARNING

The stwo-cairo prover can be significantly slower when used through Scarb. See performance section.

Scarb integrates the stwo-cairo prover which can be used through scarb prove and scarb verify commands.

Proving Cairo execution

Only packages defining the executable target can be proven. To prove the execution, you need to run the scarb execute command first, which will save execution information under the target/execute/<target name> directory. For each execution, a new output directory will be created, with consecutive number as names (e.g. execution1, execution2, ...). To clean the target directory, you can use the scarb clean command.

To prove the execution, you can run:

scarb prove --execution-id <index of the relevant execution>

You can also run scarb prove with the --execute flag, which will run the scarb execute command automatically before proving the execution for you. When running with --execute flag, you can specify the same arguments as for scarb execute command. See scarb execute documentation for more information.

The proof for the trace files inside the execution folder will be generated, and a proof.json file will be placed inside the execution directory.

Verifying Cairo proof

To verify the proof, you can run:

scarb verify <path to proof json file>

Performance

The stwo-cairo prover can highly benefit from platform specific optimizations, that are not available when Scarb is run from a precompiled binary. For the best performance, it is recommended to build scarb-prove and scarb-verify crates from source, with following compilation flags: RUSTFLAGS="-C target-cpu=native -C opt-level=3" --features="std". To use manually compiled binaries with Scarb, replace the scarb-prove and scarb-verify binaries in the Scarb installation directory, or add them to the PATH environment variable before any other Scarb related binaries. For production use, it is recommended to use the stwo-cairo prover directly.