Technical report on the Aggregation Layer of the Unicity Network: the component that records spent token-state identifiers in a sharded Sparse Merkle Tree (SMT) and produces Unicity Proofs: inclusion and non-inclusion proofs. The paper details the security model, identifies the properties needed for trustless operation (prior-state preservation), and reports the design and measured performance of a Plonky3 AIR implementation that proves it in Zero Knowledge.
This paper is also referred to as the Unicity Bluepaper.
- Latest PDF: aggregation-layer.pdf
- Source repository: github.com/unicitynetwork/aggr-layer-paper
Unicity is a novel blockchain protocol with the ambitious goal of enabling token transactions to occur off-chain and, when necessary, offline. This premise requires supporting infrastructure to guarantee that there are no parallel states of assets, or more specifically, that there is no double-spending; a property we term the unicity. It turns out that the lack of globally shared state and ordering reduces the blockchain overhead considerably. In designing this infrastructure, no compromises were made regarding its trust assumptions. This paper details the design of the Aggregation Layer, the component responsible for producing Proofs of Inclusion and Non-inclusion to the users. We analyze its design for efficiency and evaluate the robustness of its trust and security model. We then identify a single critical property that the Consensus Layer must verify on each round—prior-state preservation—and observe that the remaining desirable properties of the trustless key-value store (canonical tree shape, batch incorporation, no phantom inserts, completeness) are not required by the Unicity Aggregator's security model. This optimal statement is implemented as an Algebraic Intermediate Representation (AIR) circuit on top of the Plonky3 STARK toolkit. The implementation sustains a proving throughput in excess of 10 000 insertions per second on a single consumer-class CPU, with a succinct proof and tens of milliseconds verification time, and no trusted setup.
- Unicity Whitepaper (PDF) - protocol overview, tokenomics, and network architecture.
- Unicity Yellowpaper (PDF) - low-level protocol specification, including consensus-layer engineering details, data availability, and aggregation shard operation.
- Unicity Infrastructure: the Aggregation Layer / Unicity Bluepaper (PDF) - aggregation-layer design, sharded SMT commitments, inclusion and non-inclusion proofs, and the ZK consistency proof model.
- Unicity Execution Layer (PDF) - off-chain transaction execution, service-side privacy, user-wallet privacy, and formal security proofs.
- Unicity: Predicates and Atomic Swaps (PDF) - programmable spending conditions and trustless atomic swaps on top of the execution layer.
- rsmt-air — reference
implementation of the Plonky3 AIR proving Aggregation Layer
consistency, including the
rsmt-benchperformance harness and the adversarial tamper tests cited in Section 8. - nd-smt — earlier CIRCOM/Groth16 experiment on non-deletion proofs (Section 6 in the paper).
- zkvm-ndsmt — SP1 zkVM-based consistency proof (Section 7 in the paper), integrated to the research implementation of the Unicity Aggregator.