World ID vs. Official Documents: How Their Anchors Differ

If the title leaves you wondering what I am talking about, let me explain briefly. To prove that we are human, or that we are a unique person within an application, we usually need an anchor: something that the proof rests on.

World ID uses enrollment and verification based on iris biometrics as its anchor. An approach based on official documents, such as passports, uses the documents themselves. The difference is how broad the trust you grant is, and how long it lasts.

How broad is the trust you grant?

How is the iris-based enrollment and verification used by World ID different from the Face ID and Touch ID we use every day?

Face ID and Touch ID work locally on your device. The scope of the trust you grant is: “Does the person in front of this device match someone enrolled on it?”

With World ID, that scope becomes: “Has this person ever registered anywhere in this network?”

With official documents, it is: “Has this document ever been registered with this anchor infrastructure?”

How long does that trust last?

For Face ID and Touch ID, the trust lasts until you reset the device in your hand. For World ID, it lasts “forever.” For an official document, it lasts until the document expires. What sets World ID apart is that its anchor does not expire.

World ID has the advantage of providing a stronger basis for determining uniqueness. Official documents have the advantage of expiring. Face ID and Touch ID were designed from the outset to check whether the same person is using a device. They cannot establish uniqueness across a population, though they can serve as evidence that a human is using the device.

Sharing information in context

In everyday life, you might accept a clerk checking who you are before handing over a parcel. You might accept a bar's security staff checking that you are above the legal drinking age before letting you in. You can let a cashier know what you bought and how much you paid. You might accept your credit card company knowing that you paid a particular brand or at a particular place, but you would not want it to know exactly what you bought. Within a particular context, limits on the scope and boundaries of trust make you willing to share the necessary information with the people who need it.

For most applications—commenting, participating in a community, one-person-one-vote systems, votes restricted to members or citizens, ticket purchases, and reservations—the scope of your participation is between you and a community, you and a business, and so on. Does using a system whose anchor lasts forever fit that context?

From a privacy perspective, I would personally choose official documents. After all, personal information such as our names and ID numbers can be changed under certain conditions. Documents can be invalidated and can expire. Our irises cannot.

A permanent anchor does have appropriate uses. In a country at war, for example, identity documents may be lost or infrastructure destroyed. In that context, biometrics can be a suitable permanent anchor.