Electronic signatures may be presented as evidence in litigation. As a rule, except for the qualified signature, they are subject to the free assessment of the evidence. Since "simple" and "advanced" electronic signatures are hardly or only roughly defined by law, it is the court's responsibility to accept such a signature or not. The party wishing to present these signatures as valid must provide the relevant evidence. In the case of Swisscom, it is helpful that the advanced signatures are also subject to a rigorous audit according to the ETSI standard for "NCP+" signatures; thus, such audit reports can be used. In the case of a qualified signature, the reversal of evidence shall apply. Since the law precisely determines the qualified signature and, for example, both Switzerland and Austria offer validators for the validity of such signatures on the web, these signatures are considered valid until a party proves otherwise and thus also proves that the supervisory authority or OFCOM in Switzerland, as well as the auditors, have not complied with their obligations. After 11 years in Switzerland or 35 years in Austria, proof can also cause difficulties in the qualified field, as the documents for registration have to be destroyed. Nevertheless, the signature is still visible as "qualified".
In the context of evidence after many years, it should also be noted that electronically archived documents should be repeatedly timestamped occasionally. Algorithms may no longer be as robust. A timestamp seals the document with the latest algorithms, protecting the document's integrity, including signatures.
Qualified eIDAS signatures are only considered "qualified" in the EU (and EEA) area, and ZertES signatures are also considered qualified only in the Swiss jurisdiction. This means that when a third state chooses the law, these signatures can no longer achieve their "qualified" effect or, if necessary, become not even recognized.