Self-Sovereign Identity and Distributed Ledger / Blockchain

Lets start with details of the underlying blockchain technology, Self-Sovereign Identity concept and its potential.

Claims, Proofs and Attestations are important concepts of an identity.

An identity claim is an assertion made by the person, business or a thing. Such as “My name is Antony and my date of birth is 1 Jan 1901”

A proof is some form of document that provides evidence for the claim. Such as photocopies of passports, birth certificates, and utility bills.

An attestation is when a third party validates that according to their records, the claims are true. For example a University may attest to the fact that someone studied there and earned a degree.

1 Introduction

1.1 Bitcoin / Blockchain / Distrubuted Ledger

Bitcoin was introduced as a crypto currency with blockchain technology. It introduced the concept as a distributed storage that ensures integrity of the data and solves an integral trust issue. Blockchain consists of a cryptographically linked list of blocks, which allows only to append blocks. New blocks are added and linked after they have been verified from Blockchain nodes in the network. This process ensures the integrity because blocks in the Blockchain cannot be changed.

The blockchain was introduced as part of the peer-to-peer crypto currency Bitcoin. If a user wants to use Bitcoin, user needs to have a wallet. User manages his/her account using this wallet. User can make transactions such as buying goods and paying with Bitcoin using wallet. To perform such a transaction, the user has to transfer the right amount of bitcoins to the seller. Bitcoin utilize blockchain as transaction register to keep record of all transactions. A blockchain is a cryptographically linked list of blocks where each block consists of transactions, the hash value of the previous block and a nonce. A transaction consists of input and output amount of bitcoins as well as the address of the sender and receiver. Bitcoin uses public key cryptography where the public key represents the address of a user. Bitcoin is a public-permissionless blockchain, which means that anybody can host a copy of the Bitcoin blockchain. Miners are Special self-appointed entities of the Bitcoin peer-to-peer network, collecting transactions and try to solve a cryptographic problem. Solving this problem…