A blockchain hash proves your file existed,
but a court is not bound to accept it
A common question: why not put a hash of your file on a blockchain to prove it existed on a given date? The cryptography is sound, and the record does show existence. The gap is legal. A blockchain record is self-asserted, and no blockchain operator holds qualified trust service provider accreditation, so the burden of proving your record stays with you.
A qualified timestamp under eIDAS Art. 41 carries a legal presumption of the time and integrity of the data, which shifts the burden of proof to whoever disputes it. A blockchain hash does not.
What a court actually accepts
Blockchain hash vs qualified timestamp
Both prove existence. Only a qualified timestamp shifts the burden of proof onto whoever disputes it.
The objection worth taking seriously
The idea is reasonable. You take a cryptographic hash of your file, write it to a public blockchain, and now there is a permanent, tamper-evident record that the file existed at the block time. Anyone can recompute the hash and check it against the chain. As a technical mechanism for proving existence, this works.
People reach for it because it appears to solve the whole problem at once:
- A hash on a public chain is hard to alter after the fact
- The block time gives an approximate moment the record was written
- Anyone can verify the hash against the file without asking you
- There is no single company holding the record hostage
All of that is true. The question is not whether the hash works. It is whether a court or a regulator has to accept it when the date or the integrity of your file is the thing in dispute. That is a different test, and it is where a self-asserted record runs into a wall.
What a self-asserted record costs you in a dispute
The legal test
A blockchain record proves you wrote a hash to a ledger. It does not come with any legal presumption about the time or the integrity of the underlying file, because no blockchain operator is an accredited qualified trust service provider. A court is free to weigh it, but it is not bound to accept it, so the burden of proving your record is correct stays with you.
eIDAS Art. 41 (Regulation EU 910/2014) · ZertES SR 943.03
When the record is self-asserted, the cost lands in three places:
- If the other side questions your date, you have to explain the chain, the block time and the hashing to a judge, then convince them to rely on it. The work of proving sits on you.
- Block time is the time the transaction was mined, which is not the same as a certified time from an accredited authority, so a careful opponent can attack the gap.
- Verification depends on the ledger still being reachable and a working node. A qualified timestamp is embedded in the file and stays verifiable on its own.
A qualified timestamp under eIDAS Art. 41 carries a legal presumption of the time and integrity of the data. That presumption shifts the burden of proof to whoever disputes the document, which is the exact thing a blockchain hash cannot do.
Blockchain timestamp vs qualified timestamp
Both prove a file existed. The difference is legal recognition: whether the record stands on its own when someone has a reason to question it.
| What matters in a dispute | Blockchain timestamp | Qualified timestamp (Swiss Trust Layer) |
|---|---|---|
| Proves a file existed at a point in time | Yes | Yes |
| Legal presumption of time and integrity | Self-asserted, no legal presumption | Yes, under eIDAS Art. 41 |
| Recognised by courts and regulators by law | Not recognised by law | Recognised by law |
| Issued by an accredited QTSP | No blockchain operator holds QTSP accreditation | Swisscom Trust Services (QTSP) |
| Follows the RFC 3161 Time-Stamp Protocol | No | Yes |
| Shifts the burden of proof to the other side | Burden stays on you | Yes |
| Verifiable by a court expert without the chain | Needs the ledger and a running node | Verifiable from the file alone |
Fair to both sides
Blockchain timestamping is real and cryptographically sound for proving that a file existed. The qualified timestamp does not replace that mechanism, it adds legal standing. It is issued by an accredited provider under ZertES SR 943.03 and follows RFC 3161 . See the compliance hub.
How the qualified timestamp is applied
Swiss Trust Layer does not run its own cryptographic key infrastructure, and it does not depend on a public ledger. Every seal is backed by Swisscom Trust Services, an accredited qualified trust service provider in Switzerland.
Upload the document
Any file type: PDF, image, contract, dataset or archive. The original file stays under your control the whole time.
A qualified seal and timestamp are applied
Swisscom Trust Services applies a qualified electronic signature and a qualified timestamp following the RFC 3161 standard, through its accredited trust service infrastructure.
You receive court-admissible proof
The sealed document carries the timestamp and long-term validation data, verifiable by any PDF reader or court expert without access to any private ledger.
The timestamp follows RFC 3161 , an international standard, and the signing uses PAdES and CMS formats defined by ETSI. This is cryptographic proof embedded in the file, so a court expert or any PDF reader can verify it independently, without needing access to any blockchain.
Primary sources: eIDAS Regulation 910/2014, Art. 41 · ZertES SR 943.03 (fedlex.admin.ch) · RFC 3161 Time-Stamp Protocol
Where a qualified timestamp pays off
Anywhere the date and integrity of a file might be questioned later, a record that a court recognises by law is worth more than one you still have to argue for.
Proof of creation for intellectual property
Seal a design, a manuscript or source code and hold a qualified, dated record that the work existed before a given moment, ready to rely on if someone claims it first.
Contracts and dated agreements
A qualified timestamp fixes the exact moment a contract version existed, so there is no later argument about which draft was agreed and when.
Prior art and invention records
Lab notebooks, invention disclosures and prototype files gain a timestamp a patent examiner or court can rely on, without asking anyone to trust a private ledger.
Creative and media files
Photographers, studios and agencies can prove a file existed on a date with evidence that stands on its own, not a hash that still needs explaining in court.
Training-data and model provenance
Record the state of a dataset or model at a point in time with a timestamp that a regulator recognises by law, useful under new AI transparency rules.
Corporate records and filings
Board minutes, resolutions and filings carry a qualified timestamp that proves the moment each version existed, verifiable by any court expert from the file alone.
Backed by Swisscom Trust Services
Accredited qualified trust service provider
Legal presumption, eIDAS Art. 41
Burden of proof shifts to the other side
RFC 3161 timestamp standard
Verifiable from the file, no ledger needed
Blockchain vs qualified timestamp, common questions
Can I just put a hash on a blockchain to prove my file existed?
You can, and it does show the file existed when the hash was recorded. The cryptography is sound. The problem is legal, not technical. A blockchain record is self-asserted and is not something a court or regulator recognises by law, so if the date is challenged, the burden of proving it stays with you.
Is a blockchain timestamp legally recognised?
No blockchain operator holds qualified trust service provider accreditation, so a court is not bound to accept a blockchain record as proof of time or integrity. A qualified timestamp under eIDAS Article 41 carries a legal presumption of the time and integrity of the data, which is the difference between a technical artifact and admissible evidence.
What is a qualified timestamp?
A qualified timestamp is issued by an accredited qualified trust service provider and follows RFC 3161, the Time-Stamp Protocol standard. Under eIDAS Article 41 it carries a legal presumption of the time and integrity of the data. Swiss Trust Layer applies one through Swisscom Trust Services under the Swiss ZertES framework and eIDAS.
Does this mean blockchain timestamping is broken or insecure?
No. Blockchain timestamping is cryptographically sound for proving that a file existed at a point in time. The point of the comparison is legal recognition and admissibility, not whether the hash works. A qualified timestamp adds the legal standing that a self-asserted ledger entry does not have.
How does a qualified timestamp shift the burden of proof?
Because eIDAS Article 41 gives a qualified timestamp a legal presumption of the time and integrity of the data, the document is treated as accurate unless the other side proves otherwise. With a blockchain hash there is no such presumption, so you carry the burden of proving your record should be believed.
Give your file proof a court recognises
Create an account and seal your first document in minutes, or verify an existing sealed document to see the qualified timestamp for yourself.
Want the qualified signing detail? eIDAS qualified timestamps →
Quick Answers
Can a blockchain hash prove my document existed at a certain time?
Yes, a blockchain hash can show that a file existed at the moment the hash was recorded, and the cryptography behind it is sound. The limit is legal, not technical. A blockchain record is self-asserted and is not something a court or regulator recognises by law, so the burden of proving it stays on you.
Why is a qualified timestamp stronger than a blockchain timestamp in court?
A qualified timestamp under eIDAS Article 41 carries a legal presumption of the time and integrity of the data. That presumption shifts the burden of proof to whoever disputes the document. A blockchain record carries no such presumption, because no blockchain operator holds qualified trust service provider accreditation.
What standard does a qualified timestamp follow?
A qualified timestamp follows RFC 3161, the Time-Stamp Protocol standard, and is issued by an accredited qualified trust service provider. Swiss Trust Layer applies one through Swisscom Trust Services under the Swiss ZertES framework and eIDAS in the EU.