Identity

Centralized identities are tied to a single service. Decentralized identity is not.

We will call entities with identities "actors", because non-human entities such as companies, organizations, and bots may have identities on a social network.

Identity allows an actor to:

control an account and access private data
communicate with another actor
establish visible reputation and credibility

Desirable qualities for decentralized identities:

Allow authentication and migration between services
Allow communication across services
Unique, global, and memorable

Decentralized Identity

OAuth is currently the most successful identity standard. OAuth was created to securely transfer user credentials from one site to another. OAuth identity providers became centralized because users could not run or choose their own identity providers. (See decentralized identity protocol comparisons in Decentralizing the Social Web)

Identity in federated applications:

email
XMPP
Matrix
Diaspora: User identities in Diaspora are tied to their pod, and cannot be migrated. Diaspora uses the Webfinger protocol to discover users from other pods. User information is returned via hCard, an open microformat standard for identity.
Mastodon:
Solid

Identity in p2p applications:

P2p systems key management, key verification, key backup. Account recovery.

IPFS
Peergos
Hypercore
Gun
Ssb
Aether
Iris

Blockchain Identity

In 2001, Zooko Wilcox-O'Hearn named three desirable properties of decentralized network identifiers: human-meaningful (memorable), decentralized (global), and secure (unique). This became known as Zooko's triangle. Prior to the invention of cryptocurrency blockchains, which enabled decentralized global consensus, it was thought that only two of these three properties could be achieved at one time. Now, many projects have created protocols for naming systems that fulfill all three properties.

Namecoin
Blockstack
Handshake
Microsoft
IBM - IBM is helping to create, operate and maintain permissioned decentralized identity networks built using Hyperledger

Decentralized Identifiers (DIDs)

The DID W3C standard is an emerging standard around decentralized identifiers. DIDs are a new type of globally unique identifier that do not require a centralized registration authority, and can serve as a decentralized public key infrastructure.

The format of a DID is: a scheme identifier, followed by the DID method, followed by a method-specific identifier. A simple example: did:example:123456789abcdefghi

Reputation & Trust

Web-of-trust

P2p network can ban, but cannot take away identity

Handshake problem and collusion protection (see IRIS)

Fail cases

Account recovery. Sybils and spam Impersonation

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