Requirements for long-term archiving of electronic documents

The basic requirements for long-term archiving of electronic documents are to ensure:

• credibility of origin,

• readability,

• integrity of the content, the so-called document integrity.

Credibility of origin

• This is ensured, for example, by an electronic seal embedded in the document.

• The electronic seal confirms the authorship of the document by a particular organisation. It is not an expression of legal will; this is done by the electronic signature of an authorised person.

• By default, all documents signed in Signi are sealed with the electronic seal of the Digital factory s.r.o. organisation, which is the operator of the Signi service and whose statutory director is Ondřej Synovec.

• When using the Custom Electronic Seal function, the Digital factory seal is replaced by the electronic seal of the organization proposing the document.

• Information about the e-seal can be obtained in the electronic document viewer. Attention! Adobe Reader also displays the electronic seal under the name "signature".

Readability

The legibility of the document after many years is ensured by saving the resulting file with signatures in PDF/A format.

• PDF/A is an ISO-standardised PDF file format for long-term archiving of electronic documents.

• For more information see PDF/A format.

• The content of a PDF file is restricted - the fonts used must be embedded and must be legally intended for embedding, and must not contain videos, sounds or scripts, etc.

• Importantly, the appearance of the document may change after PDF to PDF/A conversion, e.g. due to font substitution. It is therefore ideal to have the PDF/A document already available for signing so that the appearance does not change during conversion.

Content integrity / Document integrity

A number of time stamps issued by an independent certified authority can ensure the long-term integrity of a document from the time of its creation or closure. The time stamp confirms the content of the document at a given time. Time stamps include:

• a time stamp,

• the condensed content of the document,

• identification of the authority.

If the document is modified after the time stamp has been inserted, the content of the document will not match the condensed content in the time stamp and thus a violation of the integrity of the document will be detected.

When a timestamp is inserted sequentially, the last timestamp fixes the content of the document including the timestamps inserted earlier in the document. This ensures that the previous timestamps were unchanged at the time of their validity and thus cannot be changed retroactively in the future.

Adding timestamps to documents is one of the basic functions of electronic archives. It is therefore also part of the functionality of Signi Archive. For more details, see Ensuring document integrity and the use of time stamps.

Archive certification

Certification of an electronic archive is not required for normal commercial use. However, some customers need or want it, so we are preparing it.

More information

• Ensuring document integrity and the use of time stamps
• Formát PDF/A
• Electronic seals
• IT solution for archiving electronic documents using Signi