Genetic Key

A Genetic Key is a card-like device that can unlock door's and operate machinary specifically controlled by a persons genetic code.

BioShock
In BioShock the first major appearance of a Genetic Key would be the one held by Andrew Ryan as his give's hi complete control over Raptures Security Device's Bathyspheres and even the Splicer's through pheromones though how this work's is unknown.

BioShock 2
Another appearance of a Genetic Key is in Paupers Drop where Subject Delta needs the override key that is in the possession of Grace Holloway.Later in Fontain Futuristics Delta must get a gene sample from a now heavily mutated Gil Alexander in order to make a key and gain access to Persephone.