A timestamp signature is a mechanism that certifies the integrity of a series of data — proving that this data existed at a specific moment in time and has not been altered since.
Integrity is precisely one of the core requirements that makes an electronic signature secure and legally valid for all parties involved. In this post, we explain what a timestamp signature is, why integrity matters in an electronic signature process, and how timestamp technology helps you achieve it.
What Is a Timestamp Signature and Why Does It Matter?
A timestamp signature acts as a digital seal of authenticity applied to an electronic signature, recording the exact moment a document was signed and locking its content against any future modification.
The electronic signature, as defined in Regulation (EU) No. 910/2014 (eIDAS), is a set of electronic data attached to or logically associated with other electronic data, used by the signer to sign. The timestamp signature extends this definition by adding a certified time reference — turning a simple electronic signature into a time-stamped, tamper-evident legal record.
Integrity is particularly vulnerable in the digital world, where documents can be modified quickly and without visible trace. In some cases, such as determining exactly when a contract came into force, knowing the precise moment of signing is not just useful, it is legally essential.
This is why a timestamp signature cannot be issued by one of the parties involved in the signing process. To be legally reliable, it must come from a trusted third party: the Time Stamping Authority.
In this sense, the timestamp provides an extra value to the electronic signature, not only because it guarantees the integrity of the data that makes up the signature, but also because it includes relevant information about the moment of its creation.
Integrity is a very vulnerable factor in the digital world, as there are many ways and tools to easily modify an electronic document.
In some cases, it can be essential to know exactly at what time a contract was signed, since the legal relationship with the signer begins precisely after the moment in which the contract is signed.
It is for this reason that the timestamp cannot be provided by one of the parties involved in the signature process, because in this case the guarantees of the signature’s integrity and other associated data would not be reliable.
A timestamp should be provided by a trusted third party, which is known as the Time Stamping Authority.
How the Timestamp Signature Guarantees the Integrity of the Electronic Signature
The timestamp signature guarantees the integrity of the entire electronic signature, meaning it proves that the signature and all associated data cannot have been modified after the moment of signing.
This includes:
- The electronic signature itself
- The date, time, and place where the electronic signature was made
- The email addresses of the sender and signer
- Any other electronic evidence collected during the signing process
Beyond data protection, the timestamp signature also adds evidential value. In the event of a dispute, it allows all parties to demonstrate conclusively who signed, when, and where, something that handwritten signatures on paper simply cannot provide.
What Is a Time Stamping Authority and How Does It Work?
A Time Stamping Authority (TSA) is a qualified certification service provider that acts as a trusted third party, issuing official timestamp signatures that are legally recognized.
TSAs use Public Key Infrastructure (PKI) technology, which enables cryptographic operations such as encryption and decryption. Here is how the timestamp signature process works in practice:
- When a document is signed, Signaturit sends the Time Stamping Authority a hash value representing all data associated with the signed document — including the electronic signature itself.
- The TSA returns a timestamp token (also called a time certificate), which is a new hash that certifies the exact moment of signing.
- This timestamp signature guarantees the integrity of all data in the document. If any data is modified after the timestamp is applied, the certificate is invalidated — providing instant, verifiable proof of tampering.
>> Related post: eIDAS regulation and benefits for companies
How Signaturit Uses Timestamp Signatures to Protect Your Electronic Signature
At Signaturit, every advanced electronic signature is protected by an official timestamp signature to guarantee the integrity of both the signature and all electronic evidence collected during the signing process.
The electronic evidence secured by our timestamp signature (visible in the audit trail generated with each signed document) includes:
- The email addresses of the sender and the signer
- The file name of the signed document
- The exact place and time of the electronic signature, captured via geolocation
- A full log of registered events: document sent, opened, signed, and more
By guaranteeing the integrity of the audit trail, our timestamp signature ensures that no data, and no electronic signature, can be altered after the moment of signing.
Our timestamp signature is also internationally recognized, as the Time Stamping Authority we work with is accredited by the EU. This means the guarantee of integrity extends to any country, regardless of where the electronic signature was requested or executed.
>> Related ressource to download: Are eSignatures legal in Europe?
Conclusion: Timestamp Signature, a Legal Protection You Can Rely On
The timestamp signature extends the advantages of the electronic signature far beyond what paper-based signing can offer, and gives it a level of legal certainty that handwritten signatures simply cannot match.
With a paper contract, it is impossible to determine the time or place of signing. With a timestamp signature applied to an electronic signature, this information is permanently certified and tamper-proof.
In the event of a dispute over when a contract came into force, businesses that rely on Signaturit’s advanced electronic signature can prove exactly who signed, when, and where, with full legal standing.
That is the true power of the timestamp signature: it does not just replace the handwritten signature. It makes the electronic signature stronger, more transparent, and more legally robust than anything possible on paper.
Do you have questions about timestamp signatures or Signaturit’s trust services, including registered delivery and electronic identification?
Contact our team at support@signaturit.com.
