CAIN-42 PBFT quorum-certificate evidence: storage-loss-drill-2026-09-27
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What: Every quorum certificate held by each replica of cain-mr-02 after cain-mr2-node-3 and cain-mr2-node-4 (mia, sjc) lost their storage at the same time and were rebuilt only from off-host backups, then caught up while writes continued.
Classification: MEASURED on the live multi-region cluster cain-mr-02 during a two-replica storage-loss drill
Generated: 2026-09-27T02:24:30Z
Source commitment: git 521f84c0456bf118645722073f09df140167b16b (engine 33.4-production-hardened); source is not published.

Verify in about 30 seconds (Python 3.8+, `pip install cryptography`, no CAIN code):

  BASE=https://cainstudio.online/proof/bundle/storage-loss-drill-2026-09-27/      # or https://mcpgate.online/proof/bundle/storage-loss-drill-2026-09-27/
                                                             # or https://clawx.click/evidence/storage-loss-drill-2026-09-27/
  curl -so verify_pbft_qc_bundle.py "$BASE/verify_pbft_qc_bundle.py.txt"
  curl -so PBFT_QC_BUNDLE.json "$BASE/PBFT_QC_BUNDLE.json"
  sha256sum PBFT_QC_BUNDLE.json verify_pbft_qc_bundle.py
    # expect 987c53f1dc8af84aa8243e08a6d0b1e3661e6d774adf53055ef91651b6bed74d  PBFT_QC_BUNDLE.json
    # expect ba452ce42528f11f7f5235727a65cae25a34072bc52b4711fd72581615d06009  verify_pbft_qc_bundle.py
  python3 verify_pbft_qc_bundle.py PBFT_QC_BUNDLE.json

Or open $BASE/index.html: your browser runs the same checks (WebCrypto Ed25519).

Read the verifier before trusting it: it is about 300 lines. It tampers with a certificate
in seven ways and requires every tampered copy to fail, so a verifier that accepts
everything would not pass.

Not claimed: loss of three or more replicas (beyond f=1; not safe to recover from backups, not drilled); backups on another provider (the off-host copies are on other Vultr regions); loss of the identity key (kept on host; would come from the operator's secret store); encryption at rest of the backups; independent operators or providers; third-party review; absence of bugs.