The fundamental right to informational self-determination under Article 2(1) of the Basic Law (GG) in conjunction with Article 1(1) GG has been the subject of numerous rulings since the Federal Constitutional Court's census decision in 1983. In the context of the security and anti-terrorism legislation practiced since 2001, this fundamental right has gained renewed relevance. This work focuses on § 24c of the Banking Act (KWG). This provision allows various state authorities to automatically and secretly access account information about German bank accounts and deposits. In addition to addressing the central question of the extent to which the right to informational self-determination of bank customers or account holders is violated by the regulations of § 24c KWG, a second focus of the investigation is on determining the current foundations of the right to informational self-determination. The results indicate that parts of § 24c KWG are unconstitutional due to various deficiencies.