Act on Prohibition of Unauthorized Computer Access (Tentative translation)
Act No.128 of 1999
Amendment: Act No.160 of 1999
Amendment: Act No.12 of 2012
Amendment: Act No.28 of 2013
(Purpose)
Article 1 The purpose of this Act is to prevent computer-related crimes committed via
telecommunications links and maintain telecommunications-related order as realized by means
of access control features by prohibiting acts of unauthorized computer access and stipulating
penalties therefor and assistance measures to be taken by prefectural public safety commissions
to prevent the recurrence of such acts, thereby contributing to the sound development of an
advanced information and telecommunications society.
(Definitions)
Article 2 The term “access administrator” as used in this Act means a person who manages the
operation of a computer connected to a telecommunications link (hereinafter referred to as a
“specified computer”) in relation to its use (limited to the kind realized via the
telecommunications link concerned, hereinafter referred to as “specified use”).
(2) The term “identification code” as used in this Act means a code allocated to a person who,
with regard to the specified use of a specified computer, has been granted permission from the
access administrator with authority over said specified use (hereinafter referred to as an
“authorized user”) or the access administrator himself/herself (hereafter in this paragraph
referred to as an “authorized user or the like”) so as to enable the access administrator concerned
to identify this particular user or the like as distinguished from all other authorized users and the
like. In concrete terms, it may be any of the following or a combination of any of the following
and another code:
(ⅰ) A code whose content must not, according to the instructions of the access administrator
concerned, be revealed to a third party without reason
(ⅱ) A code that has been generated from an image of the whole or a part of the body of the
authorized user or the like concerned or his/her voice using a method specified by the access
administrator concerned
(ⅲ) A code that has been generated from the signature of the authorized user or the like
concerned using a method specified by the access administrator concerned
(3) The term “access control feature” as used in this Act means a feature that has been added to a
specified computer subject to specified use or another specified computer connected thereto via
a telecommunications link by the access administrator with authority over the specified use of
the specified computer concerned to automatically control said specified use. It shall be designed
to remove all or part of the restrictions imposed on said specified use upon confirming that a