(aa) Such an encroachment may only be provided for if the empowerment to encroach makes it contingent on the existence of factual indications of a concrete danger to a predominantly important legal interest. Predominantly important are first of all
life, limb and freedom of the individual. Further, predominantly important are such interests of the public a threat to which affects the basis or the continued existence of
the state or the basis of human existence. This also includes for instance the functionality of major parts of existence-ensuring public supply facilities.
247
A state measure by means of which – as here – the personality of the person concerned is revealed to broad surveillance by the investigation authority is in principle
not appropriate to protect other legal interests of individuals or of the public in situations not giving rise to an existential threat. For the protection of such legal interests,
the state must restrict itself to other investigation powers granted to it by the respectively applicable non-constitutional law in the area of prevention.
248
(bb) The statutory basis of empowerment must furthermore provide as a precondition for secret access that at least factual indications exist of a concrete danger to the
sufficiently weighty protected interests of the provision.
249
α) The requirement of factual indications leads to a situation in which presumptions
or general experience are not sufficient to justify access by themselves. Rather, certain facts that substantiate a prognosis of danger must be ascertained (see BVerfGE
110, 33 (61); 113, 348 (378)).
250
This prognosis must relate to the development of a concrete danger. This is a factual situation in which the sufficient probability exists in an individual case that damage
will be caused by specific persons to the interests protected by the provision in the
foreseeable future without action being taken on the part of the state. The concrete
danger is determined by three criteria: the individual case, the immanent risk that a
danger will become actual damage, and the reference to individuals as triggers. Access to the information technology system to be assessed here can however already
be justified if it cannot yet be ascertained with sufficient probability that the danger will
arise in the near future, if certain facts indicate a danger posed to a predominantly important legal interest in the individual case. The facts must, firstly, permit a conclusion
concerning events which at least by their nature are concrete and predictable in time,
and secondly permit to conclude that specific individuals will be involved about whose
identity it is at least known that the surveillance measures can be deployed against
them in a targeted manner and largely restricted to them.
251
By contrast, the weight of the encroachment on fundamental rights which is constituted by secret access to an information technology system is not sufficiently accommodated if the actual occasion for the encroachment is shifted still further into the runup to a concrete danger to the interests protected by the provision that is not yet
predictable in detail.
252
It is constitutionally unacceptable to link the intervention threshold to the run-up
253
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