CrawlCheck
Proof

Proof an agent can check without trusting us.

An agent that acts on what CrawlCheck measured should not have to take our word for it. Every report is fingerprinted and each day anchored to Bitcoin; every answer an agent acts on is signed; every signed answer is entered in a log that a witness running outside our servers re-checks. Each of the three is checked on the reader’s own machine.

Proves

A report with this digest existed in exactly this form by that day, and has not been edited since.

Does not prove

That the measurement was correct. Only the first claim can be settled by mathematics.

64

sealed days

145

reports under this root

#969,516

bitcoin block

Three proofs

What each record proves, and how to check it

Each check runs on the reader’s own machine, from files that are published and can be kept.

1 · Reports

Sealed and anchored to Bitcoin

Each report’s measurements are hashed; each day’s hashes become one root, committed to a Bitcoin block through OpenTimestamps.

Proves the report existed in exactly this form by that day.

The latest sealHow it is built

2 · Answers

Signed with Ed25519

Every Resolve answer an agent receives before it reads, cites, connects or transacts carries a signature over its canonical content.

Proves the answer came from CrawlCheck and was not altered in transit or afterwards.

The signing keysThe offline verifierWhat an answer holds

3 · History

Logged, chained and witnessed

Every signed answer names its leaf in an append-only Merkle log. Each signed tree head chains to the one before, and a witness running on GitHub, outside our servers, re-checks and co-signs it.

Proves an answer was not rewritten or removed after it was logged.

The log headThe latest witness

Method

How a report becomes a proof

No wallet, no fee, no key held by us. The proof is a file, not a coin.

1Reportmeasurements only2SHA-256one digest3Merkle rootone per day4OpenTimestampstwo calendars5Bitcoin blockpermanent
  1. 1

    Measurements only

    Host, timestamp, section scores, every path and status fetched, every crawler identity and what it received, the citation state. Wording and layout are excluded, so an editorial change never breaks a proof.

  2. 2

    One digest

    Canonicalised with sorted keys and hashed with SHA-256.

  3. 3

    One root a day

    Digests sorted and folded into a Merkle tree: parent = SHA256(left || right), an odd node paired with itself. Arrival order cannot change the root.

  4. 4

    Anchored

    The root goes to the OpenTimestamps calendars, which commit it into a Bitcoin transaction.

The seal

2026-10-01

Confirmed in Bitcoin block #969,516.

Merkle root
3d3a9e26cf9f2f8552ffce2036a9c1e395eb0277596d734d8b04489438e9b017
Reports covered
145
Sealed
2026-10-02T01:17:40.343Z
Calendars
https://a.pool.opentimestamps.org
https://b.pool.opentimestamps.org
Bitcoin
block #969,516

Download the .ots proofOne report’s receipt as a single file →

Verify it yourself

ots verify -d 3d3a9e26cf9f2f8552ffce2036a9c1e395eb0277596d734d8b04489438e9b017 crawlcheck-2026-10-01.ots

The reference client checks the file against a Bitcoin node or a public calendar. No CrawlCheck server is needed, or trusted. A fresh seal reads pending confirmation until the next Bitcoin transaction confirms; ots upgrade then stores the block attestation in the file for good.

Ledger

Every sealed day

64 days anchored. Each links to its own root and proof file. Days are sealed once and never recomputed.

The 145 digests sealed under this root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24a5e399af2d9112c3219852c02c0c1cfe9f0e9160242c04cecd2c1af3c376e1
24cf81a91829ebb191ea12dc3da2a9d8bb0a75e8bdc876280090f76e05d68121
267ea64a62253e47dc1501ab6ff0faad2d442837bed13594d13b8d02e592c310
2771dd40af81a9c6398693d3e607b8117b16207ca50f2c13a4154efa3f89ec84
281d31531dce55a2c2cf47ab7a0da0dac6cce49c941641dc4eb876a5bfb1f77e
28542a2ecf8d8c2a97fa5964647965ffc522a769dbfb76be5e3e3c7f023a7415
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299bf76479eb79332bbb7df63e48a3ab6315276dabcb689a00c3d48451ca0f31
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2c3b5b795e7e434445e24a109eed7d15019ad0ab2a78ad6a8e5c7b3773a8dab8
2c7b6f6cbfaeeacab615686af8b35027b99464f273ab816fc95d64c1c935b0b8
2fa356f01619f2c5c9420502aa27ce64dd6d716cdedb641a00c142103fbb8621
322cf5716974a09a14f9762b027f08a44297dccba6ffb2d9011c56af108dfa90
327b1cfb729e24d5622cc54d7e6eee663900a6d0a4ecab14febbf5a3f0e6db78
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530af8cd44eb168a1c91c58eb1be00c77af683a5d43a23e61c731c8a47d7e083
54262667c446893b7050f4d898959eff6b39ced80dbced38385e74f382f8e2d5
555d559aeb9d05ba430c492ec272c59d2b435250e72f28dc9feeaf9afc3a9155
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57b800f8afea35e39feaa8d0979883eb71656b8d7790e1923b450c14e3a41a5a
5865c8e8a22e538bc9ba99e9f437a2fc1303542d5be9b0820a4fa609fe8ec667
588e716e9c1d8b1c043b5e3c27520de9f18527ceafa679d1aedfa359e985fa7d
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Questions about this page

QWhat does the Bitcoin anchor prove?
That a report with exactly this digest existed no later than the anchored block, and that it has not been edited since. It is a proof about time and integrity, not about correctness.
QHow do I verify a report myself?
Download the day’s .ots proof from this page, recompute the report digest from its JSON record, and verify the proof with the OpenTimestamps client against a Bitcoin node or public calendar. No CrawlCheck server is needed for the check.
QWhy exclude wording and layout from the hash?
So an editorial change never invalidates a measurement. Only the measured fields are hashed; the words around them can be improved without the proof breaking.
QWhich days are anchored?
Every sealed day is listed on this page with its digest and proof file. Days are sealed once, after they end, and never recomputed. A day sealed within the last day or so reads as pending in the reference client: the calendar holds the commitment, and the Bitcoin block confirming it is usually mined within 24 hours. The proof file here is upgraded to carry that block header once it exists, so a pending file is a proof waiting on a block, not a missing seal.