Principles of Data Access and Auditing of Digital Documents (GDPdU) is a German set of rules for archivingdata
. The regulations, which have been in force since the beginning of 2002, set out the legal obligations for the digital archiving of tax-relevant data. The GDPdU does not define any processes, technologies or systems
for archiving, but requires the unchangeability of archived data. It is a supplement to the new legal regulations of the German Tax Code (AO) and represents the view and interpretation of the tax authorities. The guidelines are binding vis-à-vis the audit authorities of companies.