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Check the versions of Duely’s list

Chain intact: 1 entry, from the origin to the last one, recomputed when this page was opened.

Each published version enters, when it is published, a register in which every line carries the hash of the previous one. Changing or removing a version afterwards would change every following hash: anyone who kept a hash would see it.

What this proves, and what it does not

The chain proves that the versions have not been rewritten since the hash you hold. The date comes from anchoring: each night the register has changed, the hash of its last line is sent to the public OpenTimestamps calendars, which write it into a Bitcoin block within a few hours; the proof then shows that this line, and all the lines before it, existed no later than the date of the block. It is not a qualified time stamp within the meaning of the eIDAS regulation.

Anchors

No anchor yet: the first one is made the night after the first publication.

Check without the service

1. Download the full register (JSON).
2. The first line starts from the origin: SHA-256 of the text “registre-sous-traitants/registre/service”.
3. For each line, SHA-256(previous_hash + content), in hexadecimal, must give back its hash; the previous hash of a line is the hash of the line before. Lines that record notices to customers publish only their hashes (their content names the publisher’s customers): the chain stays continuous.
4. The content of each “version” line holds the list of that version, to compare with the page.
5. For the date: no anchor yet; the first one is made the night after a new line. Its text and proof (.ots) will then appear above, to check on opentimestamps.org (“Stamp & Verify”) or with “ots verify” from the OpenTimestamps client.

Recorded versions