In the case of the security mortgage as a sub-form of the mortgage, the bona fide purchaser is not protected against defences against the claim arising from the mortgage (§§ 1184 (1), 1185 (2) BGB). Necessary security mortgages are the so-called maximum amount mortgage (§ 1190 BGB) and the compulsory/restraining mortgage (§§ 866, 932 ZPO).
The mortgage must be designated in the land register as a security mortgage (§ 1184 (2) BGB).