that do not send the searching agency merely a reference to further information in the
event of a match, but provide direct access to the corresponding simple basic data
under § 3 sec. 1 no. 1a ATDG, is not compatible with the prohibition of disproportionate measures. To that extent, § 5 sec. 1 sentence 2 no. 1a ATDG is unconstitutional.
The informational content of the extended basic data under § 3 sec. 1 no. 1b ATDG
is far-reaching, and can include highly personal information, as well as information
that portrays the biography of the persons concerned (see D. IV. 3. b) aa) [2] above).
From the viewpoint of proportionality, therefore, access to such information must be
substantially more limited than is the case for the simple basic data under § 3 sec. 1
no. 1a ATDG. The legislature itself therefore provides in general only for an indirect
search of these data, and makes their transfer as unmasked information subject to
the transfer regulations that govern the agency concerned. But because, in searches
of these data, the legislature also allows access to the simple basic data as unmasked information in the event of a match, it significantly retracts this restriction for
criteria-based searches, i.e., “reverse searches”. By linking a match message for extended basic data with the individualised information in the simple basic data, the extended basic data searched also become individually attributable, and can be exploited as personal information. In this way, by searching for one or more criteria – for
example, by searching for persons with a certain religious affiliation and qualification
who frequent a certain meeting place (cf. § 3 sec. 1 no. 1b hh, jj, nn ATDG) – agencies can perform a search and obtain, in the event of a match, not just the information
about which agency holds relevant information, but all names, addresses, and other
information listed in § 3 sec. 1 no. 1a ATDG about everyone who matches the search
criteria.
199
Such a far-reaching use does not take sufficient account of the significance of the
content of the extended basic data. […] Accordingly, a provision for use must be designed in such a way that if a search also reaches into extended data, only the file
number and the agency holding the information will be displayed, but not the corresponding simple basic data.
200
d) By contrast, there are no constitutional objections to the use of extended basic
data in emergencies under § 5 sec. 2, § 6 sec. 2 ATDG, even in the case of a reverse
search (cf. c above).
201
It is true that this is the broadest possible use of the data pooled in the counterterrorism database. In addition to the simple basic data, use here also includes all extended data as unmasked information, and therefore opens the way not just for the
use of data in the preparation of further investigative requests, but – as part of an assessment of a threat so as to guide further action – in defending against terrorism itself (§ 6 sec. 2 ATDG). Particularly because of the associated abrogation of the principle of separation of information between intelligence services and the police
(informationelles Trennungsprinzip), this leads to an especially severe interference
(see D. III. 3. a) aa), bb) [3] above).
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