User identity and sensitive data on the blockchain

Let us begin by discussing the prime aspect for user identity—the parameter that is used for verification. We can do this by using a person's email address, their phone number, or even a physical address. One might wonder how we can do this. It is actually very easy to verify any of the aforementioned parameters on the blockchain.  To do this, we can use a confirmation code. The user can link this confirmation code to their Ethereum account, which in turn links it to his/her private key. As an administrator, you have to make sure that it is not you who generates this code. This would give you the power to fabricate users at will. You want your users to be real and verified people to eradicate the trustless element from your blockchain. To generate these codes, we can use Twilio or any external service provider. Twilio is used extensively for SMS verification, which encapsulates phone verification.

Let's now consider the case of dealing with...