Self-Sovereign Identity Framework/Thought Model

Rieks Joosten (rieks.joosten@tno.nl)

TNO's SSI-group has been constructing a thought model around SSI that we need (and already use) to determine whether or not we have a common understanding about SSI (related topics) and efficiently straighten out any misunderstandings. This not only facilitates our work as we avoid the (endless) terminological discussions, but also helps us to deepen our understanding of what we are actually doing. This model, which we refer to as a Self-Sovereign Identity Framework or SSIF, is a work that is still in progress, but where the basics seem to have become stable. In this two-pager, we introduce the purpose for the model, its use, and a (new) definition of the term 'definition', which we need to make it all work. Additionally, a draft text is made available in which most of our current thinking about SSI is expressed. I would like to discuss this approach and what we might do to make it beneficial to all of us.

Purpose / Context

The SSIF provides a thought model and corresponding terminology that allows us to think in a precise manner about SSI within the context of its purpose(s) - which for us is the generic enablement of electronic support for (administrative) business transactions. The ability to conceptually talk about governance-, process- and technology-related topics, has proven beneficial, e.g. in discussions that compare different technologies, or discussions in which we determine of some technology is fit for the purpose we want to use it for.

Construction

As in mathematics, we construct the model from a set of assumptions (axioms) that we use, and use them to further develop the concepts that we need in order to ensure that the result is fit for (our) purpose, as stated above.

When developing the terminology, we try to specify definitions in terms of criteria that English speaking people that are interested in SSI are expected to evaluate in the same way, which allows participants in the discussions that we have to determine easily whether or not they are making the same distinctions, i.e. talk about the same thing, and to reconcile terminology disagreements. A nice consequence of this focus on criteria rather than the name we use for it, is that we generally do not object to using another name for a concept (as long as there's agreement to the criteria that we use for it).

Use

A (thought) model provides you with a specific perspective on the model's subject. The quality of a thought model can be measured by the ease it helps you solve problems, or understand issues. Being fixed at using traditional thought models can be very counterproductive, and introducing new ones very dangerous, as is easily demonstrated by the example of the introduction of the heliocentric model for computing planetary trajectories by Galileo, Copernic and others: some were excommunicated (perhaps even burnt at the stake?) for having this other perspective, even though it made computing planetary trajectories so much easier.

We won't be surprised to find opposition to thoughts we may introduce regarding SSI related stuff, but would like to request that the merits of what we do is judged by the effects it has on understanding SSI, and to resolve issues amongst people that agree to use the model/framework.

If you decided to use the model, please do so very consciously. Become aware of when you use the model, and equally important: when you revert to more traditional ways of thinking. The latter isn’t bad (see where it has brought you), it is just different. This awareness will help you to evaluate the usefulness of the model as well as of your own thinking. It may also inspire you to propose enhancements to this model (which we solicit).

Definitions in the model

One of the main characteristics of this model is its use of terminology and definitions. For terms whose meaning is generally not disputed, e.g. because there is an undisputed description in a dictionary, we use the definition as provided there. However, whenever discussions arise – often continuously – about the meaning of some term, another approach is called for.

The approach we use aims to guarantee, to the maximum possible extent, that different people will (come to) have the same understanding of such terms, and also that this understanding is relevant within the discussions they have. For us, this means: discussions that are somehow related to self-sovereign identity.

What we do is specify one or more criteria by which we can distinguish between what is, and what is not, an instance of the term we like to define. Participants in the discussion can then come up with use-case. Then, every participant applies the criteria to the use-case, and together they can see whether or not they use the criteria in the same way. If they don’t, the criteria need to be rephrased so that every participant uses it in the same way. When they use it in the same way, they can agree on the term or phrase they will be using in their discussions to refer to what satisfies the criteria, and what does not.

This method basically reverses the way definitions are used: rather than using a term and (dis)agreeing on its meaning, we look for the meaning we want to have consensus about, and then tag a name or phrase to it. Also, we ‘scope’ our definitions, i.e. limit their use to the discussions/contexts where there is consensus about the criteria. As an example, the terms defined in this chapter are valid for this chapter, but not necessarily for the other chapters in this book. Doing so allows for terms to be defined differently in different contexts.

Where's the Model?

The model is still under construction. However, we do have some text that provide the basics as we see it, which you can find here.