  A core part of the new identity management paradigm of Self-Sovereign
Identity (SSI) is the W3C Decentralized Identifiers (DIDs) standard. The
diversity of interoperable implementations encouraged by the paradigm is key
for a less centralized future, and it is made possible by the concept of DIDs.
However, this leads to a kind of dilemma of choices, where practitioners are
faced with the difficult decision of which methods to choose and support in
their applications. Due to the decentralized development of DID method
specifications and the overwhelming number of different choices, it is hard to
get an overview. In this paper, we propose a taxonomy of DID methods with the
goal to empower practitioners to make informed decisions when selecting DID
methods. To that end, our taxonomy is designed to provide an overview of the
current landscape while providing adoption-relevant characteristics. For this
purpose, we rely on the Nickerson et al. methodology for taxonomy creation,
utilizing both conceptual-to-empirical and empirical-to-conceptual approaches.
During the iterative process, we collect and survey an extensive and
potentially exhaustive list of around 160 DID methods from various sources. The
taxonomy we arrive at uses a total of 7 dimensions and 22 characteristics to
span the contemporary design space of DID methods from the perspective of a
practitioner. In addition to elaborating on these characteristics, we also
discuss how a practitioner can use the taxonomy to select suitable DID methods
for a specific use case.
