How does the data stay private with KILT?

You keep control over your data and you decide who you want to give it to. Once you give it to someone, they can check whether it’s valid or not by checking the hash. And this hash is the only thing that is stored on the blockchain.  

But privacy is more than that; it’s something that has to be provided in different ways. So, for example, if you want to go into a bar you might have to prove that you are over 18. In the real world you can choose any of the credentials you have in your wallet to prove that – your driving license, or identity card, or your student card, for example. 

And you can show this to the person on the door. They just need to see your picture and your date of birth to prove that you are over 18, but they don’t need to know your name, or anything else about you – you can choose to put your finger over it and you will still be let in. This is what we call selective disclosure and this is also a part of privacy.