MailTecK and Customer Comms receive the AENOR certification that accredits our compliance with eIDAS in the conservation of electronic signatures and seals.

The evolution of the information society towards a fully digital economy has required the creation of legal and technical frameworks to ensure the security of transactions. In today’s environment, trust no longer depends solely on agreements between parties or on an organization’s internal systems.

In Europe, this digital trust is supported by the eIDAS Regulation, which establishes the legal framework for electronic identification and trust services. In this way, eIDAS provides a secure and consistent transaction environment across the European market and has become one of the pillars of digitization in both the public and private sectors.

In this context, Qualified Trust Service Providers (QTSPs) occupy the highest level of assurance. They are not conventional technology providers, but audited and supervised entities that act as trusted third parties to ensure that certain digital evidence (signatures, seals, electronic submissions) retain their legal value over time.

Customer Communications Tecknalia, S.L., (CustomerComms), and MailTecK S.A., (MailTecK), are part of this group. On December 18, 2025, AENOR certified that our companies comply with the requirements of the eIDAS Regulation and the applicable ETSI technical standards, enabling them to provide:

• Qualified service for the preservation of qualified electronic signatures: Focused on protecting electronic signatures, ensuring that the will expressed digitally remains unalterable and valid in the face of technological changes.
• Qualified electronic seal preservation service: Important for corporate automation, this service preserves the validity of seals used by legal entities to authenticate invoices, certificates or mass documents.

One of the greatest challenges of the digital era is the longevity of electronic evidence. Unlike paper, whose degradation is physical and visible, the “degradation” of an electronic signature is mathematical and technological; its validity is not eternal by default. Signatures depend on certificates that expire and cryptographic algorithms that may become obsolete over time. A document can remain stored for years and still lose its probative value because it is no longer possible to reliably verify the original signature.

The Qualified Preservation Service (QPRES) exists precisely to avoid such a scenario. Its purpose is to preserve the legal validity of qualified electronic signatures and seals over time, even decades after their creation.

At this point it is important to clarify that QPRES is not an electronic archiving or document management service, nor does it guarantee that the document will remain readable in the future. Its function is not to preserve the “archive”, but to protect the cryptographic evidence that proves that a signature or a seal was valid at a specific point in time and that it is still valid from a legal point of view.

Receipt and verification
The process begins when the qualified preservation service provider receives an electronic document that has been previously signed or stamped, either by the platform itself or by another trusted service provider. This document is received through secure interfaces and undergoes a rigorous verification phase. This verification checks that the signature or seal is truly qualified, that it was valid at the time of use and that it has not been revoked. European trust lists and validation services are consulted for this purpose.

Preservation of evidence
Once this initial validity has been confirmed, the qualified provider keeps the necessary evidence to prove it: certificates, revocation statuses and technical metadata. Qualified signatures and qualified time stamps are applied to this set of evidence, generating a solid and autonomous proof.

Stamp expiration and resealing management
With the passage of time, and before the algorithms or seals lose cryptographic robustness, the system applies new qualified time stamps, keeping the chain of trust alive. Thus, even if the original certificate has expired or the technology has evolved, the legal validity is preserved. Even if the original document is no longer available, the preservation evidence still exists and can be used to prove the validity of the signature or seal at the time it was produced.

The main value of qualified preservation is not technical, but legal. A document whose signature has been preserved by a qualified QPRES service enjoys enhanced evidentiary force. In practice, this means that the signature or seal is presumed to be valid and authentic. If someone challenges them, it is that person who must prove that the service failed or that the evidence was tampered with, something extremely complex when a qualified audited and supervised provider is involved.

This significantly reduces risks in audits, regulatory inspections and legal proceedings, especially in sectors where documents must retain their value for many years, such as finance, insurance or legal.

CustomerComms/MailTecK’s accreditation as a preservation PSCC has a direct impact on sectors where document security and retention times are critical business factors. Some use cases are:

• Banking and financial sector: Financial institutions manage documents whose legal relevance extends over long periods, such as mortgage contracts, loans and guarantees, the effects of which can last for decades. In these cases, it is not enough to preserve the document: it is essential to be able to prove, years later, that the original signature was valid, complete and not manipulated. Qualified preservation makes it possible to maintain this evidentiary value during the legal conservation and prescription periods, which in this sector can reach 20 or 30 years, depending on the type of contract and the associated liabilities.
• Insurance sector: The signing of policies, supplements, risk declarations and informed consents is constant, and their validity can be questioned many years later, especially at the time of a relevant loss. Insurance retention periods often extend beyond the policy term, due to statutes of limitations, late claims or fraud reviews. In this context, the ability to prove that a policy was validly signed and that its contents have not been altered is critical. Qualified preservation allows the integrity and evidentiary force of electronic signatures and seals to be maintained during these extended periods, significantly reducing the risk of a policy being challenged due to defects in the electronic evidence or the loss of technical validity of the original signature.

Our new certification for the qualified preservation of electronic signatures and seals represents a firm commitment to legal security in digital environments and positions us as a strategic partner for organizations seeking long-term digital trust in their most critical processes.