Blockchain timestamping

Proof that a record hasn't been touched

Kimobox records the digital fingerprint of critical documents and records on a public blockchain. Anyone can verify the date and integrity without accessing the content.

What exactly gets sealed

Sealing a document on a blockchain does not mean uploading it anywhere: its digital fingerprint is computed — a fixed-length cryptographic digest — and it is that fingerprint, not the content, that is anchored on a public chain. From that moment anyone can verify that the document existed on that date and has not changed by a single byte, without needing to see it or to trust whoever holds it.

Content reviewed on 25 August 2026

What is published: The fingerprint, never the document SHA-256 digest: irreversible and fixed length
What it proves: Existence on a date, and integrity It does not prove authorship or the truth of the content
Legal complement: Qualified timestamp Art. 41.2 of the eIDAS Regulation: presumption of date, time and integrity
Privacy: Compatible with the GDPR The digest cannot reconstruct the document or identify anyone
Verification: Independent and perpetual Checked against the public chain, even if the company ceases to exist

A fingerprint, not the content

Only the hash is published: your data never leaves the platform.

Certain date

Verifiable proof that the record existed at that moment.

Public verification

Checkable by a third party with the document and the hash.

Tamper detection

If the document changes, verification fails immediately.

What it's used for

Records worth timestamping

Quality records and test results
Audit minutes and findings
Documentation delivered to clients and batch certificates
Working-time records and hours worked
Signed contracts and addenda
R&D and intellectual property evidence

Real examples

When sealing is worth it

Testing laboratory

Results a customer disputes

Before The report sits in the laboratory's own system. The customer claims it was altered after issue and there is no simple way to rebut that.

After The report fingerprint was anchored on the day of issue. Recomputing it on the current document and comparing against the public chain settles it.

Food industry · traceability

Cold-store temperature records

Before The records are held by the company's own system, which could also alter them. In a crisis, the evidence is self-serving.

After Each daily close of records is sealed. The chain attests that that day's data is what was recorded then, not a later reconstruction.

Engineering · intellectual property

Proving the date of a design

Before The file date depends on the operating system and can be changed without difficulty.

After Sealed at the moment of internal delivery. Temporal priority is evidenced against third parties without registering the design anywhere.

Vocabulary

Cryptography in four definitions

Hash function: An algorithm turning a file of any size into a fixed-length string. Changing one comma produces a completely different digest, and the digest cannot be turned back into the document.
Anchoring: Writing a fingerprint onto a blockchain. What is publicly recorded is a string of characters meaningless to anyone without the original document.
Public chain: A decentralised network whose records no single organisation controls. That absence of control is what makes the proof useful: nobody can rewrite it to suit themselves.
Proof of existence: Demonstration that a specific piece of data existed before a given moment. That is what sealing provides; authorship additionally requires an electronic signature.
Immutability: The practical impossibility of altering a confirmed record. On an established public chain, rewriting the past would demand disproportionate computational effort.

Frequently asked questions

What people ask us before getting started

Is confidential information published?

No. Only an irreversible hash that can't be used to reconstruct the document.

Which chain do you use?

An established public chain, with periodic batch anchoring to keep costs down.

How does a third party verify it?

With the original document and the timestamp reference, from an open verification page.

What exactly is uploaded to the chain?

Only the document cryptographic fingerprint: a fixed-length string generated with SHA-256. The document cannot be reconstructed from the digest, so no content is published.

Is it compatible with the GDPR?

Yes, precisely because what is anchored is not the document or any personal data but an irreversible digest. The chain cannot identify anyone or recover information.

What does sealing prove, and what does it not?

It proves that this exact document existed before a given date and has not changed since. It does not prove who wrote it or that its content is true: authorship requires an electronic signature.

Does it work as evidence in court?

It provides solid evidence on date and integrity, verifiable by a third party without depending on the company. Combined with a qualified timestamp under art. 41 of eIDAS, it covers both the technical and the legal presumption.

What if Kimobox ceased to exist?

Verification does not depend on us. You recompute the document fingerprint and compare it against the public chain, which is still there regardless of who wrote to it.

Timestamp your first record during the demo

We'll show you the module running with data similar to yours.

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Keep exploring

Sources

Where each figure comes from

References to the official text in force. If a standard is revised, this page is updated and the review date says so.

Regulation (EU) No 910/2014 (eIDAS), art. 41: legal effect of electronic timestamps EUR-Lex · 23 July 2014
FIPS 180-4, Secure Hash Standard (SHA-256) NIST · Current revision
ISO/TC 307 — Blockchain and distributed ledger technologies ISO · Technical committee

Blockchain document timestamping for proof of integrity

Kimobox's blockchain timestamping records the cryptographic fingerprint of critical documents and records on a public blockchain, providing proof of integrity and a certain date without exposing the content.

It applies to quality records, audit minutes, batch certificates, working-time records and signed contracts, and lets a third party independently verify that a document hasn't been altered since it was timestamped.