{
  "chain_slug": "arbitrum",
  "name": "Arbitrum One",
  "scorecard_profile": "rollup-L2",
  "evaluated_at": "2026-04-18",
  "evaluator": "layerqu-v2-scoring-agent-1",
  "v1_reference": "chainscreen-v1-archive",
  "dimensions": {
    "1_cryptographic_exposure": {
      "weight": 0.12,
      "score": 28,
      "sub_scores": {
        "1a_primitive_inventory": {
          "score": 10,
          "primitives_named": [
            "ECDSA secp256k1 (inherited Ethereum)",
            "Keccak-256",
            "BLS12-381 (Ethereum L1 settlement consensus)"
          ],
          "evidence": [
            "https://docs.arbitrum.io",
            "https://github.com/OffchainLabs/nitro"
          ],
          "note": "Inherits Ethereum primitives. Nitro client uses EVM crypto primitives."
        },
        "1b_shor_grover_pq_tag": {
          "score": 12,
          "tags": {
            "ECDSA secp256k1": "Shor-break",
            "Keccak-256": "Grover-weaken-128bit",
            "BLS12-381": "Shor-break"
          },
          "evidence": [
            "https://docs.arbitrum.io"
          ]
        },
        "1c_algorithm_family_diversity": {
          "score": 0,
          "families_represented": 0,
          "families": [],
          "note": "No PQC families deployed"
        },
        "1d_nist_security_category": {
          "score": 0,
          "mappings": {},
          "note": "No NIST PQC primitives deployed"
        },
        "1e_implementation_quality": {
          "score": 6,
          "formal_verification": "BoLD fraud proofs audited by Trail of Bits, OpenZeppelin, Consensys Diligence",
          "constant_time": "standard Ethereum libs",
          "libraries": [
            "libsecp256k1"
          ],
          "evidence": [
            "https://docs.arbitrum.io/how-arbitrum-works/bold"
          ]
        }
      },
      "total_artifacts": 3
    },
    "2_hndl_exposure": {
      "weight": 0.08,
      "score": 18,
      "sub_scores": {
        "2a_active_key_exposure": {
          "score": 4,
          "note": "$16.2B TVL, largest L2. All EOA sigs expose pubkeys on first tx."
        },
        "2b_cold_key_exposure": {
          "score": 4,
          "note": "42 months age; moderate cold-key exposure."
        },
        "2c_signature_longterm_validity": {
          "score": 5,
          "note": "Sequencer sigs and state root commitments forgeable post-Shor."
        },
        "2d_encryption_confidentiality": {
          "score": 5,
          "note": "Standard TLS; Sequencer API uses TLS/HTTPS."
        }
      },
      "total_artifacts": 1
    },
    "3_metadata_privacy_exposure": {
      "weight": 0.08,
      "score": 15,
      "sub_scores": {
        "3a_tx_graph_visibility": {
          "score": 4,
          "note": "Pseudonymous EVM transparent ledger."
        },
        "3b_rpc_mempool_concentration": {
          "score": 3,
          "note": "Single Offchain Labs sequencer controls tx ordering."
        },
        "3c_cross_chain_bridge_correlation": {
          "score": 4,
          "note": "20+ bridges; correlation across Ethereum <-> Arbitrum is direct."
        },
        "3d_retroactive_deanon_risk": {
          "score": 4,
          "note": "No shielded pool; ECDSA Shor-breakable."
        }
      },
      "total_artifacts": 1
    },
    "4_migration_architecture": {
      "weight": 0.15,
      "score": 55,
      "sub_scores": {
        "4a_crypto_agility": {
          "score": 15,
          "note": "Stylus (WASM) enables custom verification including PQC. Nitro upgrade path via DAO."
        },
        "4b_account_abstraction_key_rotation": {
          "score": 15,
          "note": "Inherits ERC-4337, EIP-7702 (Pectra). Custom sig verification via AA."
        },
        "4c_hard_fork_track_record": {
          "score": 15,
          "note": "Stylus upgrade, BoLD permissionless validation (Feb 2025). 42-month upgrade history."
        },
        "4d_hybrid_deployment_readiness": {
          "score": 10,
          "note": "Architecturally possible via Stylus precompile but no hybrid work shipped."
        }
      },
      "total_artifacts": 3
    },
    "5_deployment_execution": {
      "weight": 0.22,
      "score": 3,
      "sub_scores": {
        "5a_mainnet_pqc_pct": {
          "score": 0,
          "mainnet_pqc_pct": 0,
          "evidence": [],
          "note": "no public artifact found"
        },
        "5b_pqc_code_in_client": {
          "score": 0,
          "note": "no PQC in Nitro"
        },
        "5c_validator_pqc_adoption": {
          "score": 0,
          "note": "Centralized sequencer; BoLD validators do not use PQC"
        },
        "5d_published_milestones_count": {
          "score": 0,
          "count": 0,
          "note": "no PQC milestones published"
        },
        "5e_pqc_washing_delta": {
          "score": 3,
          "ratio": 1,
          "note": "No PQC announcements."
        }
      },
      "total_artifacts": 0
    },
    "6_supply_chain_vendor_readiness": {
      "weight": 0.25,
      "score": 7,
      "sub_scores": {
        "6a_wallet": {
          "score": 2,
          "top3": [
            "MetaMask",
            "Rabby",
            "Ledger HW"
          ],
          "pqc_roadmap_count": 0,
          "evidence": []
        },
        "6b_bridge": {
          "score": 1,
          "top3": [
            "Native Arbitrum Bridge",
            "LayerZero",
            "Across"
          ],
          "pqc_roadmap_count": 0,
          "evidence": []
        },
        "6c_custodian": {
          "score": 2,
          "top3": [
            "Coinbase Custody",
            "BitGo",
            "Fireblocks"
          ],
          "pqc_roadmap_count": 0,
          "evidence": []
        },
        "6d_rpc_hsm": {
          "score": 2,
          "top3": [
            "Alchemy",
            "Infura",
            "QuickNode"
          ],
          "pqc_roadmap_count": 0,
          "evidence": []
        }
      },
      "total_artifacts": 1
    },
    "7_governance_coordination": {
      "weight": 0.1,
      "score": 62,
      "sub_scores": {
        "7a_validator_stake_distribution": {
          "score": 10,
          "note": "Sequencer centralized (NC=1); BoLD permissionless validation since Feb 2025 improves decentralization."
        },
        "7b_upgrade_cadence_under_pressure": {
          "score": 18,
          "note": "Active DAO governance, Security Council (9/12 multisig)."
        },
        "7c_named_coordination_lead": {
          "score": 20,
          "note": "Offchain Labs (Steven Goldfeder, Ed Felten) + Arbitrum Foundation."
        },
        "7d_adversarial_coordination_precedent": {
          "score": 14,
          "note": "Sequencer outages handled; no crypto-change adversarial precedent."
        }
      },
      "total_artifacts": 3
    }
  },
  "gates": {
    "hybrid_deployment": "FAIL",
    "evidence_reconstruction": "PASS",
    "primitive_naming": "PASS"
  },
  "caps_applied": [
    "mosca_cap_60",
    "sutor_stage_cap_2",
    "casado_stage_cap_3",
    "preskill_half_dim2_dim3_dim5_dim6",
    "hybrid_gate_fail_cap_60"
  ],
  "qri": {
    "raw": 18,
    "after_caps": 18,
    "ci_plus_minus": 10,
    "band": 2,
    "band_name": "Acknowledged"
  },
  "migration_stage": 0,
  "mosca_inequality": {
    "X_signature_shelf_life_years": "5-10 (EOA with rotation possible)",
    "Y_migration_time_years_range": "10-15",
    "Z_10pct_year": 2036,
    "Z_50pct_year": 2041,
    "danger_zone_at_50pct": true
  },
  "four_scenario_grid": {
    "quantum_never": {
      "value_preserved_pct": 100,
      "privacy_preserved_pct": 100
    },
    "arrives_suddenly_pre_migration": {
      "value_preserved_pct": 15,
      "privacy_preserved_pct": 5
    },
    "arrives_slowly_post_migration": {
      "value_preserved_pct": 85,
      "privacy_preserved_pct": 70
    },
    "arrives_slowly_mid_migration": {
      "value_preserved_pct": 50,
      "privacy_preserved_pct": 30
    }
  },
  "burn_vs_rescue_policy": "undeclared (dependent on Ethereum L1 policy)",
  "pqc_washing_ratio": 1,
  "vendor_tile_summary": {
    "wallet": {
      "top3": [
        "MetaMask",
        "Rabby",
        "Ledger HW"
      ],
      "pqc_roadmap_count": 0
    },
    "bridge": {
      "top3": [
        "Native Arbitrum Bridge",
        "LayerZero",
        "Across"
      ],
      "pqc_roadmap_count": 0
    },
    "custodian": {
      "top3": [
        "Coinbase Custody",
        "BitGo",
        "Fireblocks"
      ],
      "pqc_roadmap_count": 0
    },
    "rpc_hsm": {
      "top3": [
        "Alchemy",
        "Infura",
        "QuickNode"
      ],
      "pqc_roadmap_count": 0
    }
  },
  "narrative_summary": "Arbitrum One is the largest L2 ($16.2B TVL) with strong governance and permissionless fraud proofs via BoLD, but zero quantum readiness. PQC is gated by Ethereum L1 migration. Stylus + AA give a theoretical pathway but no work shipped. Rollup-L2 scorecard applied.",
  "evaluator_notes": "No Arbitrum-specific PQC work. When Ethereum ships PQC via AA, Arbitrum can inherit via Stylus/AA. Classified Band 2 Acknowledged because Ethereum's PQC posture implicitly covers it.",
  "narrative_voiced": "Arbitrum is the biggest L2 at $16.2B TVL and its quantum strategy is to wait for Ethereum. That is not laziness, it is the correct answer for a rollup, but it does mean the Stylus and account abstraction machinery sits idle until someone upstream moves. Delegated readiness is still readiness with a counterparty."
}