must be documented when the measure is formally determined (see para. 179 et
seq. above), and the analysis by the foreign service must be limited to this aim. The
determination of such measures must be accessible to oversight resembling judicial
review.
b) Moreover, in line with the general requirements (see para. 170 et seq. above),
data relating to German citizens and persons within Germany must be separated
from traffic data. Furthermore, the telecommunications data of persons in relation to
whom the Federal Intelligence Service knows that they merit or require special protection must also be separated from the other data (see paras. 257 and 258 above).
The requirements for ascertaining that data will be used in accordance with the rule
of law remain unaffected (see para. 233 et seq. above). In this context, foreign services must also provide an assurance that the shared traffic data will not be retained
for more than six months. The Federal Government must assess whether additional
assurances can be obtained that could further ensure that the limits to surveillance
and data use arising from fundamental rights are adhered to in the context of cooperation.
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V.
In relation to surveillance measures, the principle of proportionality also gives rise
to requirements regarding transparency, individual legal protection and oversight (cf.
BVerfGE 141, 220 <282 et seq. para. 134 et seq.> with further references; established case-law). However, the requirements regarding transparency and individual
legal protection are significantly less strict for the surveillance of foreign telecommunications. To compensate for this, the principle of proportionality gives rise to special
requirements regarding independent oversight (cf. BVerfGE 133, 277 <369 para.
214>; 141, 220 <284 and 285 paras. 140 and 141>).
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1. The requirements regarding transparency of data processing call for rights to information. In principle, this is also the case where intelligence services are concerned
(cf. BVerfGE 125, 260 <331 and 332>). However, such rights to information can be
restricted to the extent necessary to ensure the effective performance of the intelligence services’ tasks (cf. BVerfGE 133, 277 <367 and 368 para. 209 et seq.>; 141,
220 <283 para. 137>). Given that surveillance of foreign telecommunications is largely carried out covertly, the rights to information of affected persons can be significantly restricted. In particular, intelligence services can be exempted from the obligation
to provide specific information on how data was obtained. Thus, rights to information
can only provide a basis for transparency and individual legal protection to a limited
extent; this must be compensated by creating an extensive independent oversight
regime (cf. BVerfGE 133, 277 <369 para. 214>; for more detail see para. 272 et seq.
below).
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2. In principle, notification requirements are a prerequisite for the proportionate design of covert surveillance measures, regardless of whether they are carried out by
intelligence services or by other security authorities. In this respect, too, the legislator
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