Is it possible to create a legally valid digital signature with other programs?

Several programs (Microsoft Word, Open Office, Adobe Acrobat, Thunderbird) offer the possibility of digital signing.

Unfortunately, if the timestamping service has not been used to sign them, these signatures may not be equal to a handwritten signature in Estonia.

The digital signature is equated to the qualified eID signature of the eIDAS regulation by the Electronic Identification and Trust Services for Electronic Transactions Act (section 25). If an e-signature matches the characteristics of a digital signature, we need to make sure it is valid. To this end, the status and validity of the signature certificate must be verifiable and linked to the time of signature. Because regular computer time can be manipulated, it is not a reliable source that can be used for signing. The mandatory standards established by the eIDAS regulation provide a qualified timestamping service as the only reliable measure for determining the time of digital signing. Therefore, a timestamp is required to verify the validity of a digital signature.  As several programs (Microsoft Word, OpenOffice, Adobe Acrobat and its analogues, Thunderbird) offer the possibility of digital signing without the timestamping service, it is often more difficult to verify the validity of signatures created with them in the Estonian legal space.

We recommend that you use DigiDoc programs for creating a valid digital signature or configure the aforementioned software to use the timestamping service.