Introduction

Digital identity is rapidly changing. Every user and agent will have their own cryptographic keys. At Shovel, we are building “decentralised contact network” (DCN) to accelerate this change towards decentralised identity.

DCN is a decentralised Layer 1 relationship chain to store relationships between two users, by a registry. DCN is social graph infrastructure for building rich personalised applications for end users. End users’ “switching cost” to new applications drops through interoperability of their social graphs on DCN. This brings “network effects” to applications by quicker onboarding of new users.

Background

Decentralised Identifier

Decentralised identifiers (DIDs) are a type of globally unique identifier for an entity to be identified in a verifiable and persistent manner. DIDs do not need a centralised registry.

DIDs are URIs that associate a DID subject with a DID document, allowing trustable interactions associated with that subject. Each DID document can express cryptographic material, verification methods, or services, enabling a DID controller to prove control of the DID.

DIDs enable a new model of decentralised digital identity that is often referred to as self-sovereign identity or decentralised identity. They are an important component of decentralised web applications. With methods like did-pkh, all blockchain wallets can be represented as DIDs.

Merkle DAG

A Merkle DAG is a Directed acyclic graph (DAG) where each node has an identifier generated by hashing the node's contents using a cryptographic hash function.

This brings some important considerations:

• Merkle DAGs can only be constructed from the leaves, i.e. from nodes without children. Parents are added after children because the children's identifiers must be computed in advance to link them.
• Every node in a Merkle DAG is the root of a (sub)Merkle DAG itself, and this subgraph is contained in the parent DAG
• Merkle DAG nodes are immutable. Any change in a node would alter its identifier and thus affect all the ascendants in the DAG, essentially creating a different DAG

CRDT

A conflict-free replicated data type (CRDT) is a data structure that is replicated across multiple computers in a network, with the following features:

• The application can update any replica independently, concurrently and without coordinating with other replicas
• An algorithm (itself part of the data type) automatically resolves any inconsistencies that might occur
• Although replicas may have different state at any particular point in time, they are guaranteed to eventually converge