What is SUTERUSU project

Suterusu is a scalable privacy-preserving second layer protocol for digital asset management. We implement and integrate the state-of-the-art trustless zero-knowledge non-interactive argument of knowledge protocol and hence attain the optimal balance between security and performance. The on-chain governance mechanism is a new attempt to bring forward liquid democracy into the blockchain ecosystem. We believe it provides the participants with much more flexibility and autonomy compared to the existing solution.

zk-ConSNARK

ZK-ConSNARK schemes realize the setup-free constant-size SNARK for the first time. It has the advantages of both categories with none of their downside. We can literally “eat the cake and have it". We see two routes moving forward to design ZK-ConSNARK schemes:

The first possible direction is by combining probabilistically checkable proof with the recently-proposed efficient subvector commitment scheme over groups of unknown order. However, the prover, in this case, might have to perform too much redundant computation to guarantee the soundness of ZK-SNARK. However, when the statement of ZK-SNARK is as specific as a confidential transaction with range proof, this extra computation overhead might be acceptable. On the other hand, we are also working on a tailored design of confidential transaction with range proof by drawing inspiration from similar schemes based on RSA group.

We can base our ZK-ConSNARK scheme on the recently-proposed Spartan scheme. The Spartan is a succinct variant of the sum-check protocol which is run with a low-degree polynomial encoding a circuit satisfiability instance. Their proof size is k* n^{-c}, where n is the size of the arithmetic circuit and k is a small constant. It is possible to achieve almost constant SNARK size since our confidential payment scheme has a pretty simple statement for the underlying SNARK scheme and c can be chosen to be sufficiently large.

Consensus

Sutersus blockchain adopts the latest BFT protocol “que sera consensus (QSC)” as the underlying consensus mechanism. QSC employs TLC (threshold logic clock) to annotate the sequence of event processing. We develop QSC based on the deconstruction of asynchronous consensus mechanism by TLC. Under the QSC mechanism, each participant proposes a potential value to agree on (e.g., a block in a blockchain), then simply “wait” a number of TLC time steps, recording and gossiping about their observations at each step. After the preset steps have elapsed, the participants decide independently on the basis of public randomness and the history they observed whether the consensus round succeeded and which value was agreed on. QSC simplifies the implementation mechanism of BFT consensus and provides basic security for Sutersus blockchain.

Governance

SUTERUSU project is founded for the community, therefore, the development of the project itself rely on the community. The project introduces liquid decentralized meritocracy as on-chain governance mechanism, dual-layer node design; both voting and delegating will be rewarded.