the legislature must provide for the immediate deletion of any highly personal data
collected and ensure that it be cannot be used at all. The deletion is to be documented in a manner that renders a subsequent review possible (cf. BVerfGE 109, 279
<318 and 319, 332 and 333>; 113, 348 <392>; 120, 274 <337, 339>).
4. Separate constitutional limits arise with regard to interplay between the different
surveillance measures. Surveillance taking place over an extended period of time,
encompassing almost every movement and expression of the person under surveillance and that could constitute the basis for a personality profile, is incompatible with
human dignity (cf. BVerfGE 109, 279 <323>; 112, 304 <319>; 130, 1 <24>; established case-law). With the use of modern and in particular covert investigative methods, security authorities must, with respect to the potential for harm inherent in the
“additive” interference with fundamental rights, coordinate to ensure that the overall
extent of surveillance remains limited (cf. BVerfGE 112, 304 <319 and 320>). The
limits on an exchange of data between authorities arising from the principle of purpose limitation (Zweckbindung) remain unaffected by this (see below, D I).
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5. Out of proportionality considerations, separate constitutional limits to covert surveillance measures may arise with regard to certain groups of professionals or other
persons, whose activities are constitutionally deemed to be particularly confidential.
The legislature must ensure that the authorities respect these limits when ordering
and carrying out surveillance measures.
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As a rule, the legislature is not required to completely exempt certain groups of persons from surveillance measures in advance (cf. BVerfGE 129, 208 <262 et seq.>),
given the already very high requirements for ordering such measures and the great
significance of an effective protection against terrorist threats for the free and democratic order (cf. BVerfGE 115, 320 <357 and 358>; 120, 274 <319>; 133, 277 <333
and 334 para. 133>) and for the safety of persons, as well as with a view to the multitude of considerations to be balanced, and, at the same time, with a view to the necessity of limiting opportunities for misuse. Rather, it may generally predicate the protection of confidentiality upon a weighing of considerations in the individual case.
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The legislature has leeway to design with regard to establishing and delimiting the
confidential relationships that are to be protected. It must balance the public’s interest
in the effective protection against threats with the weight of the measures for persons
subject to professional confidentiality who depend upon a particular degree of confidentiality. In doing so, it must not only take into account the specific weight of the interference that such a measure constitutes for these persons with regard to their generally relevant fundamental rights, but also consider its effects on other fundamental
rights, particularly Art. 4 sec. 1, Art. 5 sec. 1 and Art. 12 sec. 1 GG, or the independent mandate pursuant to Art. 38 sec. 1 GG. Insofar as it subjects certain professional groups to a stricter protection, these groups must be suitably delimited from the
surveillance targets.
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6. The principle of proportionality also sets requirements for transparency, the judi-
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