Shortly after its introduction in 2006, differential privacy became the flagship data privacy definition. Since then, numerous variants and extensions were proposed to adapt it to different scenarios and attacker models. In this work, we propose a systematic taxonomy of these variants and extensions. We list all data privacy definitions based on differential privacy, and partition them into seven categories, depending on which aspect of the original definition is modified. These categories act like dimensions: variants belonging to the same category can, in general not be combined, but several categories can be combined to form new definitions. We also establish a partial ordering between variants by summarizing results about their relative strength. Furthermore, we list which of these definitions satisfy some desirable properties, like composition, post-processing, and convexity, by either providing a novel proof or collecting existing ones.
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