A signature issued by a Time Stamping Authority over a file's cryptographic fingerprint (RFC 3161 standard) proving the file existed at a given instant and has not changed since.

Is the sealed document sent to the provider?

No: only the cryptographic fingerprint is sealed, not the file, so the document never leaves its owner's hands.

From 1 credit per seal · RFC 3161

The timestamp: a certain date for any file

A qualified timestamp proves that a document existed, exactly as it is, at a given instant — with a legal presumption of accuracy. It is the piece that turns “I already had this done” into something you can demonstrate: projects, quotes, works, code, minutes, photographs.

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Qualified eIDAS timestamp
Issued by Mensatek or by the FNMT
International standard RFC 3161

Timestamp issuedTSA · RFC 3161

File: technical-project.pdf
Fingerprint: sha256: 7d41…90bc
Instant: 2026-08-30 11:02:44 UTC
Authority: MENSATEK QUALIFIED TSU
Status: ✓ Verifiable with any standard software

Trust Service Provider
supervised in Spain Double seal
Mensatek + FNMT on every certificate ISO 27001 & ISO 9001
independently audited 10-year custody
at no extra cost Spanish engineering
operating since 1998

What exactly is a timestamp?

Technically, it is a signature issued by a Time Stamping Authority (TSA) over a file's cryptographic fingerprint, following the international standard RFC 3161. In practice it means two guarantees: that the file existed at that instant and that it has not changed by a single bit since — any later modification breaks the verification. The file itself never leaves your hands: only its fingerprint is sealed.

When the timestamp is qualified under the eIDAS Regulation, the law grants it a presumption of accuracy of the date and time it indicates and of the integrity of the data (art. 41.2 of Regulation EU 910/2014): whoever disputes it will have to prove otherwise.

Here we can say it: Qualified

Mensatek is a Qualified Provider of electronic trust services for timestamping, audited and supervised in Spain, and included in the European Commission's trust list (check it on the Trusted List). You can choose Mensatek's qualified timestamp (1 credit) or the FNMT's (2 credits), or use both.

How it works

Sealing takes seconds

Choose the file

Any format: PDF, images, video, code, archives… From the dashboard or via API, one by one or in batches.

Its fingerprint is sealed

We compute the cryptographic fingerprint and the TSA issues the seal with the exact instant. Your file never moves from where it is.

Keep the seal

You receive the seal in the standard format, verifiable with any RFC 3161-compatible software, today and twenty years from now.

Real cases

What a certain date is used for

Intellectual property

Authorship and priority

Designs, manuscripts, music or code with proof of prior existence.

Engineering

Projects and works certifications

Project versions sealed at every milestone; deadline disputes settled.

Tenders

Bids and submissions

Prove your bid was closed before the submission deadline.

Compliance

Minutes and internal records

Inventories, audits or logs with guaranteed integrity and date.

Claims

Photographs and surveys

Images of damage sealed the moment they are taken.

Software

Deliveries

Seal every version delivered to the client: what was delivered and when.

Frequently asked questions

About timestamping

What legal value does a qualified timestamp have?

The eIDAS Regulation (art. 41.2) grants it a presumption of accuracy of the date and time and of the integrity of the sealed data. In practice, it flips the discussion: you don't have to prove the date; whoever denies it must rebut the presumption.

Is my document sent anywhere?

No: what gets sealed is the file's cryptographic fingerprint, not the file. Your document — a confidential contract, an industrial design — never leaves your hands.

How much does it cost?

1 credit per Mensatek seal (between €0.029 and €0.043) or 2 credits per FNMT seal. Relative to what it prevents, it is the cheapest trust service there is. Full rates on the pricing page.

How is a seal verified years from now?

The seal follows the RFC 3161 standard: any compatible software can verify it without depending on us. The timestamping authority's certificates are published in our Certification Policies & Practices.

Combine it with the rest of the platform

One account, one credit balance and one API for the whole platform.

Give a certain date to what you have created

From 1 credit per document. Create your account and seal your first file in two minutes.

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