PDF / A is a format for long-term archiving of digital documents, which has been standardized by the International Organization for Standardization (ISO) as a subset of the Portable Document Format (PDF). The standard specifies how the elements of the underlying PDF versions must be used with regard to the long-term archiving. There are both mandatory and non-approved ingredients.
The specification of PDF / A-3 was published on 17 October 2012. A major extension compared to PDF / A-2 share the container is: Any file types can be embedded in PDF / A-3  A PDF. / A-3 document can in this way, for example, the raw data is attached, with which it was created. The standard regulates the archive capability of the embedded files themselves are not PDF / A-compliant.