Time of signing in the Estonian digital signature scheme

Abstract

There is a widespread misconception among some lawyers, technologists and the public that the Estonian digital signature scheme provides reliable proof of the time when a document was digitally signed. In this article Tõnu Mets and Arnis Parsovs show that the legal requirement to establish the time of signing is not met in practice. The related legal requirement that the validation of the digital signature should confirm that the certificate was valid at the time of signing is also not met. The authors analyse the legal consequences of this, and discuss possible solutions for the issues that arise. They note that digital signature schemes used in other countries implementing Regulation (EU) No 910/2014 of the European Parliament and the Council of 23 July 2014 (eIDAS) are likely to share the problems discussed in this article.

Index words: Estonia, European Union, Digital signatures, Electronic documents