Digital identity cards, not digitised identity cards

You all know who Marshall McLuhan was, right? And that he predicted not only the internet but its impact on society

Born in Canada in 1911, McLuhan studied at the University of Manitoba and University of Cambridge before becoming a lecturer at the University of Toronto. He rose to prominence in the 1960s for his work as a media theorist and for coining the term “global village”, which was a prescient vision of the internet age.

Half a century ago, he said of the networked world he predicted that “In the new electric world, where everybody is involved with everybody, where everybody is involved in complex processes, the old identity cards, the old means of finding out who am I, will not work”. I wish that more people would take this on board, give up trying to digitise the old identity systems and start building the new digital identity system we need.

Here’s an example. I notice (via my friends at One World Identity) that the Australian state of New South Wales is soon to provide citizens with “digital driver’s licenses, stored on a user’s smartphone, allowing them to ditch their physical ID card”. I read that article and it seems to me that these aren’t digital driver’s licenses or anything like them. They are digitised driver’s licences, nothing more than virtual shadows of their mundane progenitors. They have no functionality beyond their heritage in industrial age bureaucracy and provide absolutely nothing new to the new economy.

We need digital identity, not digitised identity, a point I intend to make loud and clear in Washington on 26th and 27th March, where I will be chairing the 2nd KnowID conference. And I’ll be talking about McLuhan, because McLuhan had this notion of identity as smeared across entities, depending on the relationships and interactions between identities (what Ian Grigg calls “edge” identity). If this is indeed the correct vision for post-industrial online identity (and since he was right about most other things, I’m certainly not going to call McLuhan out on this one) then what would it mean for the driving licence?

Well, I (and others) have long argued that shifting to an infrastructure where transactions are between virtual identities and enabled by credentials is the way forward. Hence the right way to see a driving licence is as a bundle of credentials. How would we use those credentials? To make claims that we need in order to enable the transactions. In Phil Windley’s “Self-Sovereign Identity and the Legitimacy of Permissioned Ledgers” he says, if I interpret him correctly, that a claim is the process of providing a credential and authenticating its use in order to obtain authorisation. I like the “claims are processes” way of thinking and it seems like a reasonable working definition, so let’s move forward with that, using my favourite Three Domain Identity (3DID) as the framework.

 The Three Domain Identity (3DID) Model

The attributes that are needed in the Authorisation Domain might be very varied, but for sake of the discussion, let’s assume that in the case of the driving licence there are three claims that should be supported:

  • A policeperson might need to know who you are.

  • A car rental company might need to know that you are allowed to drive.

  • A bar might need to know that you are over 18.

Now the digitised driving licence doesn’t know who is asking, what they are asking for, or whether they are allowed to ask for it. So it shows everybody everything and (in the general case) they have no idea whether any of the claims are true or not. But a digital driver’s licence could know all of these things. So when the policeperson asks your digital driving licence who you are, your digital driving licence can check the digital signature of the request and the authorisations that come with them. The digital driving licence knows that the bar can ask if you are over 18, but not who you are because it’s none of their business – although the licence may return a service provider-specific meaningless but unique number (MBUN) that the bar can use for loyalty (and barring). I cannot stress just how much of a new idea this is not. A decade ago John Elliot, Neil McEvoy and I wrote a chapter called “This Is Not Your Father’s ID Card” for the book “Digital Identity Management”. In it, we said that:

Because computers, biometrics and digital signatures can work together to disclose facts about someone without disclosing their full identity. Your ID card could, for example, send a message to a machine confirming that you are over 18 without disclosing who you are or what your citizen number is.

I’m sure we were not the only people to have realised this. The problem then, and now, is that the people in charge of identity cards, and driving licences, and passports and all of the other identity infrastructure, still see these documents only as dumb emulations of paper and not as what they are: nodes in an identity network. They are nodes and our identities, to go with Ian’s formulation, are the edges between them.

All very well, I can hear you saying. All very nice in theory. But what about deployment? How would will you connect up all of the bars and car rental counters and police cars and so on. What would the person in the bar use to interrogate your digital driving licence? Well, their digital driving licence of course! Surely one of the defining characteristics of the digital age driving licence that has a computer in it and is now a node is that… it can talk to other driving licences. There is a beautiful symmetry to this: no digital driving licence is different from any other digital driving licence, nor privileged above any other digital driving licence. No need to for custom equipment. Every has the same digital driving licence – you, the cop, the barman – but these licenses are loaded with different claims.

So this is how Phil Windley’s claims work in practice then: I want to get a drink so in the Authorisation Domain the barman sets his digital driving licence (a smartphone app) to request a claim for IS_OVER_18 and then via NFC, Bluetooth or QR code interrogates my digital driving licence (a smartphone app). My smartphone app sees that his request is signed by a valid licensing authority and has not expired and checks what credentials it has to hand. It discovers two virtual identities containing the relevant IS_OVER_18 attribute: one from the Driving License Authority and from my car insurance company. It selects the first one and sends it to the barman’s app.

(The virtual identity contains a unique identifier, a public key, a number of attributes and a digital signature.)

The barman’s app checks the signature and recognises that it is valid. Since the barman is using his smart driving licence app it either stores or has access to the public keys of the driving licence authorities, car insurance companies, car rental companies and so on. My smart travel app would have similar information for airlines and car rental companies, hotel companies an so on. The barman’s driving licences sends back a message encrypted using the public key. My app can decode this, because it has the corresponding private key, so in the Authentication Domain it asks for me to authenticate myself. I use my fingerprint or PIN or whatever and the app decodes the message. Then it replies to the barman’s app. The barman’s app now knows that I have the corresponding private key and thus it can accept that IS_OVER_18 applies to me.

The claim as process – I want to see a virtual identity that contains a credential that includes this attribute / here is a suitable credential / OK, so prove it is yours / here you go, I decoded your message / Thanks, now I’m happy to serve you – delivers both security and privacy and shows that we use digital identity to create an infrastructure that goes far beyond emulating our broken physical industrial age identity system to provide something so much better,

It’s time to move on from the cardboard age to the communication age, and I hope that you’ll join me at KnowID to discuss all of that latest developments in the digital identity space and to formulate practical strategies for making the long-overdue change to digital identity in the mass market, whether centralised, decentralised, federated or whatever else might work.