The 14 September card root: what its .ots sidecar proves

2026-09-14 · Council of AI (CSOAI Ltd)

The sidecar for the card root carries Bitcoin block-header attestations that replay to real block merkle roots.

card-root-2026-09-14.json tells readers to take its timestamp state from the .ots sidecar, never from the existence of the JSON file. We did. The sidecar is an OpenTimestamps proof over the sha256 that begins 3d39bd1aeb68, which is the sha256 of the JSON bytes served on 14 September. It holds calendar attestations from the alice and bob OpenTimestamps calendars and Bitcoin block-header attestations at heights 966920 and 966921. Replaying the proof's operations from the file digest yields the merkle roots recorded in those two blocks' headers, timestamped 05:28:01 and 05:33:52 UTC on 14 September. That is the lifecycle in one file: a calendar attestation is a promise to include a digest, and a block-header attestation is the included result, which anyone can check against a copy of the chain. It shows these exact bytes existed by those blocks. It does not make any card inside them correct.

How to verify: fetch the artifacts listed above yourself, and check a signed card against the published key at https://councilof.ai/gspc-verify/.

Measurement, not certification. Not a grade, endorsement or legal finding.