In previous texts, we explained what a qualified timestamp is and how signature maintenance ensures the validity of documents for years. Now we raise an important question: can only one party to a contract take care of maintenance, or should both parties do it?
There is no formal obligation for signature preservation to be carried out by both parties to a contract. Legally, it is sufficient for one party to stamp the document with a qualified timestamp and secure it against loss of credibility.
But beware - this solution is good only in theory.
In practice each party should independently take care of the maintenance of its copy of the document. Why?
A bilateral agreement bearing qualified electronic signatures has the same legal force as a paper version with handwritten signatures. But the mere presence of a signature is not enough to make the document valid in, say, 10 years.
Each party, for its own legal security, should:
As a result each party has its own independent proof of validity, which can be used in court, in an office or in an audit.
In Poland, the leader in qualified validation and maintenance of electronic signatures is Asseco Data Systems, which operates, among others, through the platform podpisano.pl and the service WebNotarius (Certum by Asseco).
WebNotarius is the first qualified service in Poland that provides both long-term validation and maintenance of electronic signatures and seals, in compliance with eIDAS regulations. With this service, documents can be secured for up to 30 years, as also confirmed by the case study SzuKIO.pl - is a search engine for judgments of the National Board of Appeals (NAC), the Court of Justice of the European Union or the Courts concerning public procurement. The extensive case law database is particularly useful during procedural processes related to public procurement. SzuKIO.pl is used by the administration, companies executing public contracts of significant value, consultants and lawyers.
The system independently detects when an existing timestamp expires, performs a re-validation and adds a new timestamp - without user intervention. Thanks to such solutions, each party to a contract signed not only with a qualified signature, but also secured with a timestamp, can be sure that its copy of the document will be verified and recognized in the future - even after years or technological changes. This type of automation eliminates the risk of human error, delays and negligence - and thus increases the evidentiary value of the document in the long term.
Document type | Archiving format | Content | Validation |
Contracts, protocols | PAdES-LTV/LTA | Signature, TSA, OCSP/CRL in PDF | Adobe Reader, WebNotarius Viewer |
Invoices, XML e-data | XAdES-A | Same thing, but in an XML structure | Dedicated XML validators |
PAdES-LTV:
XAdES-A:
Formally - yes. A contract signed by both parties and preserved by only one of them, can be considered valid.
But:
Therefore each party should have its own maintenance mechanism - preferably automated, maintenance-free and resistant to technological change.
Remember...
...If you need... | Choose |
Contracts, protocols, bids in PDF | PAdES-LTV |
Structured data, XML invoices, B2B reports | XAdES-A |
Easy validation by the customer/official | PAdES-LTV |
High flexibility and integration with systems | XAdES-A |
✔️ Lease agreement signed online? Both parties should keep their versions with maintenance, because after 3 years there may be a dispute over the deposit.
✔️ B2B contract with qualified signatures? Implementing maintenance in the company's repository is a minimum of security.
✔️ Project documentation in PDF with signatures of several people? The PAdES-LTV format preserves completeness - each signature and timestamp can be independently verified.
Summary
