Formal paper on Unicity's off-chain execution model. It defines token ownership through signatures, proves no double-spending and no blocking, and analyzes service-side and user-side privacy.
- Latest PDF: unicity-execution-layer.pdf
- Source repository: github.com/unicitynetwork/execution-model-tex
- Presentation: video recording
EasyCrypt security proofs of the main theorems:
This paper introduces the Unicity Execution Layer, a modular component of the Unicity framework enabling secure off-chain transactions while maintaining trustless double-spending prevention. We present a formal security model where token ownership is represented by public keys and transfers require digital signatures. We prove three fundamental security properties: (1) no double-spending---each token state can be spent at most once, (2) no blocking---only the legitimate owner can prevent a token from being spent, and (3) service-side privacy---the Unicity Service cannot link transactions with the same token. The user-side privacy is addressed by introducing generalized multi-public-key signature schemes that allow one secret to generate multiple unlinkable public keys, and an interactive and non-interactive concrete instantiations, enabling private transactions with stable public identity with minimal key management overhead.
- 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 ("smart contracts") and trustless atomic swaps implemented using the predicates.