Diamond Framework: Reputation-Weighted Validator Selection via Verifiable Non-Transferable Reputation

Proof-of-stake secures admission and deterrence with a single instrument, financial capital, and that is the source of its structural tension: high collateral requirements deter honest but capital-constrained validators, low requirements expose the network to Sybil attacks. The Diamond Framework replaces a fraction of the financial stake with verifiable, non-transferable reputation, so the admission barrier falls without claiming that the full Cost of Attack is preserved; that question is left open in the paper.

This deposit is the frozen PDF snapshot of the manuscript, v0.2.2, with its source. v0.2.2 is a text release: it rewrites in the paper the three statements that v0.2.1 could only correct in an errata sheet. Section 6 now describes the validator-bound statement the implementation delivers (a Poseidon leaf carrying the validator address as a public input); the verification cost is the measured cold path, 286,144 gas (781 gwei break-even, 31x margin at 25 gwei) instead of the earlier ~206k composition with an inlined key; the collusion detector declares W as an external input and the on-chain alert as a non-sanction; and the financial floor is stated as a minimum admission cost, not a guarantee.

Artifact: diamond-framework-2026-10-25.pdf, 43 pages, 591875 bytes, SHA-256 89e718373158285821ac04d1a9280c7ff85baa8c03dbc4b8df9a6da481dd39b9; source main.tex, 155945 bytes, SHA-256 2a6384d2c5eec1e2c122352ab3fa89e2fd46cb4ca374b28c2b489ca16334368c. The claim registry that binds each quantitative claim to the script reproducing it is sealed by an eleven-file anchor root (SHA-256 abe9c5535eb1dd7e462b49f19b52b828a9cfe235ccbcd32819f5daa37fe56bf7) and timestamped with OpenTimestamps. That seal is still pending Bitcoin attestation when this version is deposited. The receipt over the immediately preceding root did complet- Bitcoin blocks 972956, 972959 and 973014-  and it seals the same eleven files but for one corrected ratio in Section 9 (the Bulletproofs alternative costs 23x the deployed Groth16 path, not 31x the retired 206k composition); it is archived in verification/ots-history/ and is not cited as evidence for this version, because a seal over other bytes is not a seal over these.

Verification is offline and reproducible: 310 Foundry tests, the numerical suite (38 scripts in the manifest) and an 11/11 audit gate. Limits are declared rather than omitted: the Groth16 verifier deployed on the Avalanche Fuji testnet uses a committed development key, carries no ceremony and has recorded no certified admission; the recursive option and Teleporter cross-subnet latency remain deferred; and the external audit is pending. Bitcoin enters only as an external witness of the anchor, because a receipt sealed inside the root it witnesses would be circular.

Erratum (2026-10-28) — the gas figure this version calls “deployed”. The 286,144 gas quoted for the cold admission-verification path was measured with the V3 Groth16 key, which has three public inputs. The verifier that admits validators today installs M4d's four-input key (root, epoch, validator, certifiedNorm), and a three-input key cannot be installed at all: the verifier requires publicInputs.length == ic.length - 1 and the registry passes four, so the call reverts PublicInputsMismatch(3, 4). The deployed figure with the installed key is 306,253 gas cold / 247,211 warm, measured 2026-10-28 at commit be49336 (forge 1.5.1, solc 0.8.33, optimizer off, evm_version = cancun); 286,144 remains correct as V3's number. The figures derived from it move by 1/G and no conclusion changes: the break-even gas price is 730 gwei rather than 781, the ingest-over-verification ratio 2.23x rather than 2.39x, Bulletproofs over Groth16 21.2x rather than 22.7x, and the margin at 25 gwei 29x rather than 31x. The full erratum, with the reproduction script and the measurement log, is at docs/paper/releases/v0.2.3-errata.md (entry E-01). This version's text is intentionally not rewritten; the correction ships in v0.2.3.