Self-sovereign identity (SSI) is a decentralized identity model. When applied in the Internet of Things domain, this model enables digital trust independently of the protocol agreed among peers for data exchange. Each peer has full control on its own identity and it must publish a decentralized identifier on a trusted public utility. Such identifiers are the basic building block to provide authentication in a decentralized fashion. However, SSI framework requires secure management of the cryptographic material required for building the digital identity. Each device is the true owner of its own identity, therefore a proper key management system needs to be integrated for autonomously generating identity keys and produce digital signatures.