Self-Sovereign Identity Specifications: Govern Your Identity through Your Digital Wallet using Blockchain Technology

Digital identity is one of the biggest challenges in cyberspace. This field has been evolving for many decades with a number of Identity Management (IDM) models being proposed and employed; however, few were able to solve the issue of sovereignty of an identity and storage-control of its associated personal and confidential data. Self-Sovereign Identity (SSI) was introduced to solve this crucial issue offering a user full sovereignty of their identity and storage-control of their associated personal and confidential data. Alongside ownership of an identity, it maintains all private information in a Digital Wallet which is owned and controlled by the user. However, SSI is an emerging IDM, therefore it requires careful evaluation of various aspects of SSI for it to become an operative IDM. This paper proposes several specifications to evaluate any SSI solution. Subsequently, it analyses two emerging SSI solutions uPort and Sovrin. Finally, an evaluation of uPort and Sovrin SSI is performed utilising the proposed specifications, highlighting their strengths and limitations.