A legal framework for electronic signatures
The basic legal principles that support the use of electronic signatures are not defined by eIDAS. Rather, they are found in contract law, where an offer to enter into an agreement followed by the acceptance thereof constitutes a binding agreement. Thus, in the absence of legal requirements specifying the form of a contract, level of signature or method of authentication, a contract can be entered into by any means, including on paper, orally, or with a basic electronic signature.
The eIDAS regulation is a legal framework governing the use of electronic signatures, but it doesn’t mandate their use per se, nor does it have any impact on contract law. The regulation states:
This Regulation does not affect national or Union law related to the conclusion and validity of contracts or other legal or procedural obligations relating to form.
In fact, a basic electronic signature is sufficient and indeed legally valid for the vast majority of private transactions, B2B, B2C, and between private persons. To dispel any doubts in this respect, eIDAS explicitly states this fundamental principle:
An electronic signature shall not be denied legal effect and admissibility as evidence in legal proceedings solely on the grounds that it is in an electronic form or that it does not meet the requirements for qualified electronic signatures.
Note that in some cases, national laws may require more than a basic electronic signature, e.g., when specific KYC (know your customer) requirements apply. Or, although it is not a legal requirement for a valid signature, a party might want to authenticate the counterpart with a certain level of security when the transaction entails a high business risk.