Solution

Reiy is an intent-based batch auction protocol on Sui. Trades are expressed as protected intents, solvers compete in sealed auctions, and settlement is enforced on-chain by Move contracts.

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Architecture

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Solution

Reiy follows the batch-auction pattern established by earlier CoW protocols - intents, solver competition, CoW matching - but introduces structural changes that remove trusted operators and eliminate griefing vectors:

• Benchmarks are executable bids, not passive reference quotes: always settlement-ready, no separate liveness path.
• Bonds scale with committed scores (bond >= score x grief_factor), not fixed. Griefing costs more than it extracts: no ban lists or reputation needed.
• Every phase is permissionless: epoch advancement, bid submission, allocation selection, even the fallback path. No trusted operator required beyond Sui validators.

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Intents (protected trade instructions)

An intent is an escrowed on-chain asset plus a constraint (minimum payout, deadline, slippage). Unlike signed orders that must be executed as-is, intents give solvers flexibility with partial fills, routing across venues, or CoW matching, as long as the user’s minimum is met. This flexibility is what makes batch auctions efficient.

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Batch auctions

Multiple intents are grouped into timed auction cycles (epochs). Solvers compete during each epoch by submitting bids: executable settlement plans that commit to specific scores and bonds. Batching enables:

• CoW matching: Alice sells A for B, Bob sells B for A. They cross inside the batch with zero slippage.
• Competitive pricing: Solvers bid to offer the best surplus; users benefit from the competition.
• Uniform pricing: All intents in the same pair receive equal proportional improvement above their floor.

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Off-chain coordination, on-chain settlement

The protocol splits work: the coordinator runs the auction off-chain (low latency, low cost), while settlement is enforced on-chain by Move contracts. The coordinator has no authority over user funds. It collects bids, ranks them, and signs certificates, but final settlement is always verified by the contracts.

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PairBenchmarks (executable benchmarks)

Benchmarks are derived from competing pair-scoped bids submitted by solvers, not from standalone reference quotes. Each PairBenchmark is a set of executable bids: always settlement-ready, always fallback-selectable. This removes the need for a separate reference quote liveness path.

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Score-scaled bonds

The required bond scales with the solver’s committed score: bond >= score × grief_factor. High-score bids require proportionally more collateral. This makes grief attacks economically self-limiting without needing cooldown timers, ban lists, or reputation systems.

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Uniform surplus ratio (EPSR)

All intents in the same directed pair receive equal proportional improvement above their floor, checked within a configurable tolerance (1–5 bps). This guarantees fairness within each pair: no solver can give one user 10% improvement and another 0.1% in the same batch.

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Protocol guarantees

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Trust model

No single party controls the outcome. The coordinator selects the winner, but the contracts enforce the rules.

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