Time-stamping to guarantee the integrity of your electronic documents

What is time-stamping, and what does it mean for business? While time-stamping is used to record the date and time of an event in the traditional sense, it is particularly important when it comes to electronic transactions and document processing.

In a context of digital transition, the transformation of your business processes brings with it new challenges. Keeping proof of exchanges, tracing actions carried out on a document online, knowing the exact date of a document's electronic signature are all functions attributed to time stamping.

But what exactly is it used for, and how does it work? When should time-stamping be used, and what are its advantages? appvizer provides you with the essential keys to understanding!

Find out in this article:

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Timestamping: definition

Electronic time-stamping: date and no longer edit

Electronic time-stamping is the process of associating a precise (to the nearest second) and reliable date and time with data, as securely as possible.

In a context of dematerialization of corporate documents and processes, time-stamping has a number of applications, including :

• certifying the date of an electronic signature,
• proving the existence of a document
• guaranteeing transaction times (purchases, sales, etc.),
• validate receipt of electronic mail,
• comply with legal archiving and document retention deadlines,
• date an electronic invoice at the time of issue, etc.

☝️ The time/date stamp used cannot be a device using a system clock (such as a computer). As the date and time can be changed manually locally, this does not give any legal value to the creation date of a document, for example.

Similarly, while online tools can be used to change the creation or modification date of a document, or even the date of the last access to a file, they are not legally recognized time-stamping devices either.

How, then, can the reliability of the time-stamping process be guaranteed?

Certified time-stamping: guaranteeing security and compliance

Certifiedtime-stamping is the cryptographic guarantee that time-stamped data or documents have not undergone any subsequent modification, and that the date recorded is accurate.

According to the European eIDAS regulation, qualified time-stamping guarantees :

• the existence of the document at a precise date and time, defined using a Universal Time Coordinated (UTC) source;
• the integrity of the document, certifying that its content has not been modified since that date.

This is where a PSCo time and date stamp (Prestataire de Services de Confiance) comes in. Thanks to its secure, FIPS-compliant hardware, this service provider delivers a certified time-stamp, which takes the form of an electronic seal or a time-stamp token for an electronic document.

In order to qualify as a Time-Stamping Authority (TSA), this third-party trust organization must comply with the requirements set out in the RFC 3161 standard.

How time-stamping works

A Time-Stamping Authority uses Public Key Infrastructures (PKI). Here's how it works:

1. A hash value is created and sent to the HA by the client application (such as a unique identifier);
2. Any changes to be made to the file will necessarily be communicated to the HA server;
3. The time-stamping authority associates the hash with other information, including the reference time. The HA's private key is used to digitally sign the result, after which a time-stamp token is issued and sent to the client;
4. This token, containing all the important time-stamping information, is received by the client application and recorded in the document or code signature.

ℹ️ When the timestamped file is opened, the client application authenticates the TSA and verifies that the timestamp has been issued by a trusted TSA. A new hash of the data is calculated, then compared with the original one. If any changes have been made after time-stamping, the unreliability of the data is reported.

What is the benefit of a document time-stamping solution?

Giving proof value

The time-stamping of an electronic document has legal value: it acts as irrefutable proof in the event of legal dispute or litigation.

Applying a time-stamping token or electronic seal, via the time-stamping service, makes it possible to prove :

• document integrity or non-alteration: no changes have been made to the document since it was time-stamped ;
• the document's anteriority: it was issued on the date of the time-stamp;
• acknowledgement of receipt: the stamp attests to the date and time of receipt of an e-mail;
• the document's enforceability: it constitutes a piece of evidence that can be invoked before a legal authority;
• traceability of all actions carried out during document processing.

Guarantee the conformity of your documents and transactions

Using a reliable system dedicated to the electronic time-stamping of documents can be of paramount importance for issuing dematerialized documents and carrying out transactions with your customers, partners and suppliers, in full compliance.

Its enterprise applications guarantee the compliance and reliability of various types of documents and transactions, including :

• electronic invoices
• dematerialized pay slips
• certified copies of digital documents with legal value,
• electronic document signatures, etc.

Certified time stamps and electronic signatures

To guarantee the legality of an electronic signature, the date and time of the computer used do not constitute legal proof.

On the other hand, a time-stamped signature brings the following benefits:

• the security and integrity of the signature are reinforced ;
• time-stamped content is irrevocable;
• the date and time of signature are more reliable;
• the confidentiality of the signatory is preserved, in compliance with the RGPD;
• faster processing of files;
• procedures and decision-making are accelerated, etc.

💡 The certified time-stamping process of an electronic document signature enables the validity of the signature to be perpetuated with long-term validation (LTV). The signature can thus be authenticated, and the authenticity of the document can therefore be proven at any time.

Selecting trusted third parties

For any company, it is essential to use a certified time-stamping system to guarantee the existence, integrity and anteriority of its electronic data and documents.

In many cases, time stamping is included with your electronic signature solution, as with DocuSign, which manages, sends and signs electronic documents, while integrating the time stamping system.

By opting for an " electronic time-stamping service provider " (PHSE), as defined by the RGS (référentiel général de sécurité), offering a FIPS (Federal Information Processing Standard) compliant service, you ensure the security and legality of all your processes.

This is the case with Universign, a Trusted Service Provider (TSP) qualified under the European eIDAS regulation and recognized as a trusted authority by Adobe, which offers qualified time stamping directly integrated with its solution's electronic signature and seal services.

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Legal value at the click of a button

To ensure the best possible guarantee of document reliability and security, don't hesitate to turn to trusted time-stamping authorities or third-party time-stampers, for the advantages we've outlined.

More than just guaranteeing the date and time of your documents, transactions and electronic signatures, time-stamping enables you to trace with certainty every event and stage in a document's lifecycle, from creation to storage, management and distribution. This makes it particularly useful for collaborative platforms and digital workspaces.

Are you ready to time-stamp your documents with peace of mind?