Evidence and time stamps

The evidence file behind every signature

A signature is defended with proof. With every signed document, KimoSign keeps who signed, how they were identified, when, from where and on which exact version of the document, time-stamped and, if you wish, anchored to a blockchain.

What it is and why it matters

The evidence file is the record that accompanies every signature and makes it defensible: it captures how each signer was identified, the time stamp of each signature, the document's cryptographic fingerprint, the IP address and device, and the full trail of the request; optionally, the fingerprint is anchored to a blockchain so anyone can verify the date and integrity without relying on KimoSign.

Content reviewed on 17 October 2026

Time stamp: Art. 3(33) and 3(34) of the eIDAS Regulation Definition of the electronic time stamp and the qualified one
Effect of a qualified time stamp: Presumption of date, time and integrity Art. 41(2) of the eIDAS Regulation
Requirements for a qualified time stamp: Art. 42 of the eIDAS Regulation Linked to an accurate time source and signed by the provider
Document fingerprint: SHA-256 Hash function standardized in FIPS 180-4
Blockchain: Optional, fingerprint only No content or personal data leaves the platform

Identification

Method used by each signer: email, PIN by text or email, handwritten stroke or certificate.

Time stamp

Reliable date and time for every signature, qualified when the level requires it.

Document fingerprint

SHA-256 digest that detects any change, however small.

Technical context

IP address and, if authorized, the signer's approximate location.

Workflow trail

Sends, reminders and signatures, each with its time, from start to finish.

Blockchain anchoring

Optional: the fingerprint is recorded on a public blockchain so it can be verified without us.

What it contains

What is recorded for every document

Declared identity and contact details of each signer
Authentication method and result of each verification
Date and time of sending and of each signature, with a time stamp
IP address and approximate location of each signer
Cryptographic fingerprint of the document before and after signing
Blockchain anchoring reference, when enabled

Blockchain

Verification that does not depend on us

If you enable it, the fingerprint of the signed document is anchored to a public blockchain. Neither the document nor any personal data is published: only an irreversible digest that lets anyone check the date and integrity.

Only the fingerprint is published, never the content
GDPR-compatible: it cannot be used to identify anyone
Verifiable by a third party with the document and its reference

Typical scenarios

When someone says they never signed

Services · contract renewal

A customer denies having agreed

Before The company only had an email saying "fine". The customer claimed it did not refer to that version of the contract.

After The evidence file shows the PIN sent to their phone, the time of signing, the IP address and the fingerprint of the exact version signed.

HR · employment paperwork

A dispute over the date of an addendum

Before The addendum signed on paper had no certain date and each party remembered a different day.

After The time stamp fixes the moment of each signature. The dispute is settled with a fact, not with anyone's memory.

Engineering · client deliverables

A document modified after signing

Before A version with a change in scope was circulating and nobody knew where it had come from.

After When the signature is validated, the fingerprint does not match: the document was altered after signing and the authentic version is the one in the evidence file.

Vocabulary

Evidence vocabulary

Evidence file: The set of technical data that accompanies a signed document and proves how, when, by whom and on which version it was signed. Also known as an audit trail.
Electronic time stamp: Data in electronic form that binds other data to a particular moment in time and proves that they existed at that moment (Art. 3(33) eIDAS).
Qualified electronic time stamp: A time stamp issued by a qualified provider in accordance with Art. 42 eIDAS. It enjoys a presumption of the accuracy of the date and time and of the integrity of the data.
Blockchain anchoring: Recording a document's fingerprint on a public blockchain. It lets anyone check that the document existed on that date and has not changed, without knowing its content.
Non-repudiation: The property that prevents a signer from credibly denying they signed. It is built on identification, sole control of the signing means and the evidence.

Frequently asked questions

What people ask us before they start

What is the evidence file for?

To defend the signature if anyone disputes it. It proves who signed, how they were identified, when and on which version of the document, which is exactly what is argued over when a signature is challenged.

What is a time stamp?

Proof that a piece of data existed at a specific moment. When it is issued by a qualified provider, Article 41(2) of the eIDAS Regulation presumes the accuracy of the date and time it indicates and the integrity of the data it refers to.

What does the document fingerprint prove?

That the document has not changed. The SHA-256 fingerprint is recalculated from the file and, if it does not match the one recorded in the signature, someone has altered it.

Is blockchain anchoring mandatory?

No. It is an additional layer for those who want verification independent of any vendor. The time stamp and the fingerprint already prove the date and integrity.

Is the signer's location stored?

Only the approximate location derived from the IP address and, on mobile devices, whatever the signer authorizes. It is contextual data that strengthens the evidence, processed in accordance with the GDPR.

How long is the evidence kept?

The evidence file stays with the signed document for as long as you keep it in KimoSign. Specific retention periods are agreed in the service contract.

We will show you a real evidence file

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Keep exploring

E-signature evidence, time stamps and blockchain

Every document signed with KimoSign includes an evidence file with the signer's authentication method, a time stamp, a SHA-256 cryptographic fingerprint, the IP address, the device and the full trail of the signing workflow.

Optionally, the fingerprint is anchored to a public blockchain so that any third party can verify the document's date and integrity without accessing its content.