Dave is a permissionless, interactive fraud-proof system. This repo contains the Dave software suite, including support for both rollups and compute (i.e. a one-shot computation, like a rollup without inputs):
- Solidity smart contracts;
- off-chain testing node in Lua;
- off-chain reference node in Rust;
- dispute algorithm specification.
This project uses git submodules.
Remember to either clone the repository with the flag --recurse-submodules, or run git submodule update --recursive --init after cloning.
To run the PRT Lua node, follow the instructions here.
Our fraud-proof system is called Dave. Just Dave. It's neither an acronym nor an abbreviation, but a name. Like most names, it should be written in lower case with an initial capital, that is, "Dave".
Dave is permissionless. This means anyone can participate in the consensus. Since anyone can participate, there's the possibility of Sybil attacks, where an attacker can generate an army of fake personas and try to shift the consensus in their favour.
Dave's security is one of N: a single honest validator can enforce the correct result. It doesn't matter if it's you against the world. If you're honest, Dave's got your back; you can fight a mountain of powerful, well-funded crooks and win, using a single laptop, in a relatively timely manner.
Dave is inspired by the David vs. Goliath archetype.
Dave uses the Cartesi Machine as its execution environment. The Cartesi Machine is a RISC-V emulator. Its onchain implementation can be found here. The Cartesi Machine state-transition function is implemented in two layers: the big-machine and the micro-architecture. The former implements the RV64GC ISA, while the latter implements the much smaller RV64I ISA. Using a technique called machine swapping and leveraging good compilers, we implement in Solidity only the micro-architecture's state-transition function, while the execution environment can support a much larger set of extensions.
Nevertheless, Dave was designed to be agnostic on its execution environment. As long as one can provide a self-contained state-transition function, Dave will work.
The first implementation of Dave is based on the Permissionless Refereed Tournaments (PRT) primitive. The paper can be found here. The maximum delay and expenses grow logarithmically on the number of Sybils, and hardware and bonds are both low and constant, regardless of the number of Sybils. As such, the defenders have an exponential resource advantage over the attackers (making the algorithm secure), it's easy to become a validator (low bonds and hardware requirements, making the algorithm decentralized), and delay grows slowly.
Although delay grows logarithmically in the Permissionless Refereed Tournaments (PRT) algorithm, the constant multiplying this logarithm is high, harming its liveness.
The second implementation of Dave will be based on the eponymous Dave algorithm, which improves the liveness of PRT, while maintaining its attractive security and decentralization properties. We've published our initial research here.
The project is still in its prototyping stages.
Thank you for your interest in Cartesi! Head over to our Contributing Guidelines for instructions on how to sign our Contributors Agreement and get started with Cartesi!
Please note we have a Code of Conduct, please follow it in all your interactions with the project.
The repository and all contributions are licensed under APACHE 2.0. Please review our LICENSE file.
