Signatur von PDF/A Dokumenten
PDF/A is a series of standards of the International Organization for Standardization (ISO) for the use of PDF for long-term archiving of electronic documents. The only adopted standard, with reference to the PDF version 1.4, is PDF/A-1. Published as ISO 19005-1:2005, PDF/A-1 establishes requirements for a standard-compliant PDF and regulates the use of PDF / A, mainly with regard to the screen display and printout.
A PDF/A document must be visually reproducible. It is particularly necessary that in a PDF/A document all used fonts and images are included and the corresponding document is marked as PDF/A in the document properties . This also means that in a PDF/A document any external document references or links are not allowed because they may become unavailable over time. For the same reason all necessary colour tables and additional colour information need to be included in the document, e.g. via a colour profile.
A PDF/A document may not be encrypted. In addition, no (selective) locks of various functions of the file, such as printing or copying data, may be applied. Moreover, any active elements (such as JavaScript) are prohibited, as these script functions may change the document content at runtime. A PDF/A document may also not contain any no audio or video content.
Currently, a new version of the standard (PDF/A-2) is in the process of standardization and will be based on a more recent PDF standard. The publication of this standard is expected during the year 2009.
