For many in the identity industry, hearing “self-sovereign identity” (SSI) automatically makes you think “blockchain.” And, if you’re like me, as soon as you hear blockchain, you think it’s too darn early to play the blockchain drinking game and move on. In the early days of SSI, most of the discussion was, in fact, about identity on a blockchain. That association did a disservice to the concept of SSI. SSI is no more dependent on using blockchain technologies than a passport is dependent on a particular type of paper.
What is SSI?
SSI is an architecture that guides technological decisions. It is not a piece of software to install or a service you can purchase. In an SSI model, the individual is the single most important entity in a transaction. That individual controls what happens with their information. For people to trust the individual’s information, there needs to be some measure of both technical and societal trust in the veracity of that information.
That’s the puzzle the technology has to solve. How do you create a digital identity with information that has been verified (or possibly asserted) by a third party (like the government), that allows an individual to control what information is shared, does NOT allow the third party to know about the transaction, and yet can be verified as accurate by whoever is receiving the data from the individual?
What is a Blockchain?
Several features associated with blockchain technology suggest it is a good fit to solve that problem. At its most basic, a blockchain is a distributed database with data spread across any number of nodes in a network. Enough math is involved to guarantee that the information in those nodes can only be altered with a clear record of who modified it and when.
With the right technology, such as a digital identity wallet, an individual can share this cryptographically secure information with any other interested party. Suppose that information was initially issued by a known, trusted entity, and the data cannot be changed (only added to in a visible way). In that case, no one needs to check back with that issuer to see if the information is accurate. The issuer will, in fact, have no idea that this information was shared at all. The individual is in control, and privacy is preserved. Win!
You might find this article interesting if you’d like to read more about how SSI and blockchain can transform society.
Other Options for SSI
We have some obvious wins here by using blockchain technology to support SSI. Why isn’t it the One True Way? Because blockchain has some significant limitations. For one thing, it is computationally expensive (which means slow and power-hungry). It is also far more complicated than is actually required for most use cases (if you haven’t seen Figure 6 in this NIST publication, it sums this argument up nicely).
Decentralized identifiers (DIDs) are a fundamental part of the SSI model. There is an entire registry of possible methods to use and support DIDs. Some are blockchain-based, but others rely on the OpenID for Verifiable Credentials specifications. There are options; it is better to understand your current infrastructure, what problem you’re trying to solve, and decide what technology you need to support. Don’t try to make your problem fit the tool, especially when other tools are available.
Wrap Up
SSI’s core principle is about enabling individuals to own and control their digital identities. This architecture can be implemented through various technologies, not limited to blockchain. Blockchain offers a way to decentralize and secure these identities, but it’s not the only method to achieve the principles of SSI.
And if you play the blockchain drinking game, too, I hope you read this late in your day and have a designated driver to get you home.
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>It is also far more complicated than is actually required for most use cases (if you >haven’t seen Figure 6 in this NIST publication, it sums this argument up nicely)
Ha! That diagram was the visual output and synopsis of the results of almost 2 years of R&D into the applicability and viability of blockchain technologies from my program back in the day! Glad that it remains useful.