What is identity?

How many times a day do you prove who you are? Opening a bank account, checking in at a hotel, asking for a student discount at the cinema, confirming your age on a website. Most of the time we do it without thinking. Yet each time the same thing happens: someone wants to know something about you, and you prove it.

Identity is not one thing

When we hear "identity" we think of an ID card. In daily life, though, we are almost always asked for small pieces of it. The hotel wants your name and document number. The cinema only cares whether you are a student. A hospital needs to know that the person in front of it really is a doctor. A shop online only needs to know that you are over 18.

Each of these pieces is an attributeA single fact about a person: name, date of birth, profession, whether they are a student.. Your identity is the sum of your attributes.

Saying it is not enough

"I am a student" convinces nobody; you show a student card. "I am an engineer" is not enough either; a diploma is requested. The value of these proofs comes from who issued them. The university issues the student card and the diploma, the state issues the ID card. The other side does not really trust you; it trusts the institution behind the document.

Every time you prove something, the other side looks for three answers:

• What is being claimed?For example, "this person is a student at Example University".
• Who is claiming it? Did that university really issue the document, or did someone make it up?
• Is it still valid? Could the studies have ended, or the document have been withdrawn?

What changes in the digital world?

In digital identity the questions stay the same; what changes is who answers them. Today a person answers them by looking at a document and, if needed, picking up the phone. With a digital credential, software answers in seconds without calling the institution. For that, the credential carries proof of "who is claiming it" (a digital signature) and a way to find out whether it is still valid.

In the next pages we look at today's problems, then at the different models of digital identity. By the end of this chapter you will know the "trust triangle" that Tamga Network is built on.