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This is a timestamp certificate with legal and technical validity, it's backed by the existence of specific data that can only be generated from the contained documents, and that was written with certain date in a public, immutable, distributed database known as Bitcoin's blockchain.
The certificate is this very file that you've downloaded or received. You can re send it to third parties by any means available to you, and the may validate it independently.
You're seeing this document in https://api.constata.eu which is a trusted origin, it's been verified before showing it to you.
Visit https://api.constata.eu to learn more about the guarantees it offers.
In case Constata's web validation is not available, or the company's endorsement was not enough, you can access a detailed audit of this certificate clicking here.
We describe the process and technologies involved in the issuance and validation of this certificate Terminology is available in the Glossary at the bottom.
To leave evidence that the documents contained in this certificate existed before a certain date CONSTATA produced files, called BULLETINS, that contain the HASHES of each PART of a DOCUMENT contained in this CERTIFICATE, and the HASHES of the DIGITAL SIGNATURES applied to some of thos PARTS.
Then, we left proof of the HASH> of each BULLETIN in separate BITCOIN TRANSACTIONS that were written in the BITCOIN BLOCKCHAIN distributed database on a date referred to as BLOCK DATE
We can establish then that DOCUMENTS, and DIGITAL SIGNATURES applied to them, existed at the time BLOCK DATE of the BULLETIN associated with them.
You can validate that the DIGITAL SIGNATURES applied to DOCUMENTS are correct independently, but the link between those signatures and actual persons and companies is only endorsed by CONSTATA's signature that was applied to this file as a whole.
Unlike timestamps, validating signatures requires you acquire a copy of constata's public key from a trusted source. Constata's website is one such way. If you are unsure about Constata's public key, then you cannot be sure about who signed this document, and who's endorsing the signer identities.
This file contains the timestamp and digital signature validation routines implemented in the Javascript language, you can find it in this file's source code. When you opened your web browser, this routine was executed, and several public copies of the Bitcoin blockchain were queried in search for bulletin fingerprints.
The process was successful, otherwise, this certificate would have shown an error message.
If you're not familiar with Javascript, or if you rather perform the validation manually, this are the steps to follow. This steps are to be reproduced in a command prompt on any Linux, MacOS or compatible operative system.
With this process, we validate that the BULLETINS were published on the BITCOIN BLOCKCHAIN at the matching date. This way we can know that the DOCUMENTS referred to existed at that date.
Calculate its HASH.
$ shasum -a 256 /path/to/bulletin_3753.txt
4392c54ece14cfa72379605a2dc379db76f3c633a774627ed4c36ec5942cd87d
Query the BITCOIN TRANSACTION to find the BULLETIN HASH. Its transaction id is 4298475fff3fa39d7b5fd5673794a912b084d55eb2d5ec6c9775eec9e9d252ac.
With this process we validate all the DOCUMENTS are being referenced by one of the included BULLETINS we just validated, and therefore, existed in the date specified by the matching BULLETIN.
This document is composed of 3 parts, was included in BULLETIN #3753, with date {loading date}
Calculate its HASH.
$ shasum -a 256 /path/to/1_full_zip_file
475f8ab85b8d208ec9cf069be9791cc7e72a21c2b3839467cfa6c2185576ef31
Find this part's HASH in BULLETIN 3753 you saved previously, if the 'grep' command returns '1' it means the HASH is present there.
$ grep --count 475f8ab85b8d208ec9cf069be9791cc7e72a21c2b3839467cfa6c2185576ef31 /path/to/boletin_3753.txt
1
Calculate its HASH.
$ shasum -a 256 /path/to/1_1_diploma_en.html
f2257ff051e8219a8e579751d6d25e77158a3b883822f6075fefdacf2658751c
Find this part's HASH in BULLETIN 3753 you saved previously, if the 'grep' command returns '1' it means the HASH is present there.
$ grep --count f2257ff051e8219a8e579751d6d25e77158a3b883822f6075fefdacf2658751c /path/to/boletin_3753.txt
1
Calculate its HASH.
$ shasum -a 256 /path/to/1_2_scores_en.html
880691db30bfb7e5f734d8e65dd10c61d9d9bbe9f320a2d1516325e94aea8827
Find this part's HASH in BULLETIN 3753 you saved previously, if the 'grep' command returns '1' it means the HASH is present there.
$ grep --count 880691db30bfb7e5f734d8e65dd10c61d9d9bbe9f320a2d1516325e94aea8827 /path/to/boletin_3753.txt
1