IDs, DIDs, and VCs

The „ID“ in what is traditionally called „IDs“ (like passports, state IDs, or drivers licenses being abused as „IDs“) does not stand for „identifier,“ but „identity.“ The distinction is important: an old-fashioned passport says that the person running around with a particular face (identifier!) in fact has a particular identity verified by a government. You are providing the identifier (face, fingerprint, DNA, …), the government only associates those identifiers with your real-life identity in a verifiable way, so you can assert your identity. In a paper/plastic-world, verifiability has its limits – we all know the scenes in spy movies where the protagonist has a stack of forged passports in a Zurich safe deposit box.

In the SSI-world, the user generates identifiers in the form of DIDs, as many as they want, and within whatever ecosystem they want. Often, an individual might chose to use different identifiers in different contexts, for example to avoid being traced, or simply to keep different „worlds“ apart. This is the equivalent of a person being called „Joe“ by friends, „Joseph“ by colleagues, „Little Joe“ in their hobby band, and „Professor Smith“ when giving lectures. The same person could also call himself „Zaphod“ when ordering a drink in a coffee shop („What’s the name on the order?“) – this does not matter, as long as they remember that when the drink is ready to be picked up.

A government or some other trusted authority can then issue a VC that a DID is associated with a particular real-life identity – one could associate several DIDs with one identity. So, what many countries call an „E-ID“, within an SSI-world, would be a VC.

Which VCs an ecosystem acknowledges for identity assertion is up to its governance. An educational ecosystem might accept VCs issued by university registrars offices for identity assertion if the learner cannot provide any government-issued VC.