III.
Personal data stemming from strategic surveillance may only be shared with other
bodies if a clear and sufficiently specific statutory basis exists that makes such sharing contingent upon the protection of legal interests and upon certain thresholds that
reflect the weight of interference resulting from strategic surveillance. The sharing of
personal data stemming from strategic surveillance is only permissible for the purpose of protecting legal interests of particularly great weight and requires, as a
threshold, indications that a specific danger may emerge (konkretisierte Gefahrenlage) or sufficiently specific grounds for the suspicion of criminal conduct (hinreichend
konkretisierter Tatverdacht). This does not apply to reports provided to the Federal
Government, insofar as these are exclusively intended to provide political intelligence
and prepare government decisions.
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1. Where an authority makes data collected by it accessible to another body through
data sharing, this amounts to a separate interference with fundamental rights (cf.
BVerfGE 100, 313 <367>; 141, 220 <334 para. 305>; established case-law). This interference must be measured against the fundamental rights which the original data
collection interfered with (cf. BVerfGE 100, 313 <367>; 141, 220 <334 para. 305>;
established case-law).
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2. Given that it results in new interferences with fundamental rights, data sharing
requires a separate statutory basis that must be clear and sufficiently specific (cf.
BVerfGE 65, 1 <46>; 100, 313 <389>; established case-law).
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As data sharing amounts to a separate interference with fundamental rights, sharing
or exchanging data stemming from particularly intrusive surveillance measures without a separate statutory basis is impermissible; such a statutory basis also serves to
warn of such sharing and to clarify the applicable conditions.
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The principle of legal clarity sets limits to the use of chains of references in legislation. A clear statutory basis is not lacking merely because a provision refers to another provision. However, such references must be limited, they must not become unclear through the referencing of provisions that concern different situations and must
not result in excessive difficulties in their practical application. Obscure chains of references are therefore incompatible with the constitutional requirements (cf. BVerfGE
110, 33 <57 and 58; 61 et seq.>).
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3. In substantive terms, both the statutory authorisations for data sharing and the
specific data sharing measures must satisfy the proportionality requirements (cf.
BVerfGE 65, 1 <45 and 46>; 100, 313 <390 et seq.>; 141, 220 <327 para. 286>).
Data sharing must be suitable and necessary for achieving a legitimate purpose. According to established case-law, the determination of whether a data sharing measure is proportionate in the strict sense must be based on the weight of the change
in purpose resulting from data sharing compared to the purpose of the original data
collection and, on this basis, on the criterion of a hypothetical re-collection of data.
According to this criterion, it is decisive whether it would be permissible under consti-
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