In practice, there is not even uncertainty about the different types of signatures, especially what legal requirements there are for various purposes. There is a clear difference in European law between a regular electronic signature, an advanced electronic signature and a qualified electronic signature.
Ordinary electronic signature
The ordinary electronic signature is a signature that is linked to electronic data, for example a document from an e-mail. Think of a scanned ordinary signature. The ordinary electronic signature usually does not meet the "sufficiently reliable" requirement. This type of signature is quite easy to forge. However, this also depends on the circumstances discussed in the legislation.
G modified electronic signature
The advanced electronic signature meets the requirements set out in Article 26 of the eIDAS Regulation. These requirements are:
Is uniquely linked to the signatory;
Enables identification of the signatory;
Creates electronic signature creation data that the signatory, with a high level of confidence, can use under his sole control and;
Prepared manner on the electronic file to which it relates, that any subsequent change of the data can be detected. The advanced electronic signature can be applied easily to most documents. Both the sender and the recipient can sign electronically, so that the entire signing process is safely handled digitally.
G custom electronic signatures, like handwritten signatures, are unique to each signer. ValidSign follows a specific protocol called PKI. PKI requires the provider to use a mathematical algorithm to generate two long numbers called keys. One key is public, and one key is private. When a signer puts a digital signature, it is created using the signer's private key, which is always kept safe by the signer. The mathematical algorithm acts as a cryptograph, creating data that was used with the signed document, a hash, and encrypting this data. The damaged encrypted data is the digital signature. The signature also includes the time when the document is signed. If the document is changed after signing, the digital signature is invalid.
The qualified signature
A qualified electronic signature is a signature with a qualified certificate. This certificate can be added digitally to the document (using a signing service such as ValidSign). Certificates are issued by recognized certificate service providers. The certificate that most accountancy firms do know is the PKI government certificate (professional certificate shows that the AA / RA Accountant is registered with the NBA). In some cases, such as when filing annual accounts (SBR Assurance), you must sign with a qualified certificate.