Definition(en): ISDOC is a type of Extensible Markup Language (XML) file format specific for transfer of financial documents. It allows paperless exchanging of invoices and other documents, processing and portability among companies, public administration authorities and individuals. It was defined by “A Working group for Electronic Standards of data exchanging” in ICT Union (formerly SPIS). The “Declaration on common approach in the area of electronic invoicing in the Czech Republic” was signed on 16th October 2008. It represents a Czech customization of UBL standard https://www.iso.org/standard/66370.html. ISDOC file enables enveloped signatures including advanced IETF/W3C XML digital signatures conforming to the ETSI XAdES specification. This signiture records the 6.0.1 version of ISDOC file format, developed in May 2014. More information about other versions can be found: http://www.isdoc.cz/index.php?id=1316.