  This paper introduces a new method of Blockchain formation for reliable
storage of personal data of ID-card holders. In particular, the model of the
information system is presented, the new structure of smart ID-cards and
information on these cards are proposed. The new structure of Blockchain -
"Blockchain Tree" allows not only to store information from ID-cards but also
to increase the level of security and access control to this information. The
proposed Subchains system allows to integrate Blockchain of the lower level to
Blockchain of the higher level, allowing to create a multilevel protected
system.
