idp2p.github.io

IDP2P

Experimental, inspired by ipfs, did:peer and keri

Background

See also (related topics):

• Decentralized Identifiers (DIDs)
• Verifiable Credentials
• IPFS
• LIBP2P
• Key DID
• Peer DID
• Key Event Receipt Infrastructure

Problem

Each did method uses its own way to implement decentralized identity. Most of them are based on a public source of truth such as a blockchain, dlt, database or similar. Others are simple, self-describing methods and don’t depend on any ledger technology e.g. did:peer, did:key, keri. Each method has its own pros and cons with respect to design-goals.

IDP2P Solution

IDP2P is a peer-to-peer identity protocol which enables a controller to create, manage and share its own proofs as well as did documents. The protocol is based on libp2p, in other words, it can be considered ipfs of decentralized identity. IDP2P has following features:

• Self-describing identity (like did:keri, did:peer, did:key)
• Based on libp2p pub-sub protocol, so it can be stored and resolved via network
• P2P network provides one ledger per identity
• Only identity owner and interested parties are responsible for storing and verifying identity
• DIDComm can be achieved via pub-sub
• Service endpoints are not necessary in document because identities can communicate directly via network

Consensus Mechanism

When an identity event has occured, the change is published over the idp2p network. All subscribers verify the new change and update their own ledger (if they consider the incoming change to be suitable).

There are two pub-sub commands:

• get: when a peer wants to subscribe to an identity, it publishs a get command with id over the network.
• post: when a peer receives a get command or an identity change occured, it posts identity information to subscribers in order to reach a consensus.

An identity is also a topic to subscribe to (i.e. the ledger is based on subscription)

Identity

An idp2p identity includes a unique identifier, a microledger, and a DID document.

{
    "id": "did:p2p:bagaaieratxin4o3iclo7ua3s3bbueds2uzfc5gi26mermevzb2etqliwjbla",
    "microledger": {},
    "document": {}
}

id is the unique identifier of identity. It uses id generation like did:peer. id should be generated in the following way:

• Generate an inception block
• Get json string of the block
• Convert it to bytes
• Get SHA-256 digest of bytes
• Encode it with multibase and multicodec(like ipfs)

sample id: bagaaieratxin4o3iclo7ua3s3bbueds2uzfc5gi26mermevzb2etqliwjbla

The microledger represents backing storage of the identity and it includes id, inception, and events for the identity

  {
    "inception": {},
    "events": []
  }

inception includes keyType, next, and recovery public key digests

{
  "keyType": "Ed25519VerificationKey2020",
  "nextKeyDigest": "<base32 value of next public key digest",
  "recoveryKeyDigest": "<base32 value of recovery public key digest"
}

events is array of identity changes wherein each event is linked to the previous one. The first event is linked inception block.

{
    "payload": {
      "previous": "<inception-hash>",
      "signerKey": "by5gtwpufy4zfnog4j..",
      "nextKeyDigest": "by5gtwpufy4zfnog4j..",
      "change": {
        "type": "SetDocument",
        "value": "bdu3gqtjc6ks52.."
      },
      "timestamp": 1642418658
    },
    "proof": "bx6svqb6if5yaflgoumdff7j.."
}

There are three event types:

• SetDocument: proof of did document change, requires value property which is a hash of the did document.
• SetProof: any proof about identity, requires key and value properties.
• Recover recovery proof of identity requires keyType and recoveryKeyDigest properties.

did_doc is described in DIDs Spec. Only the latest document is stored in the identity.

{
    "id": "did:p2p:bagaaieratxin..",
    "controller": "did:p2p:bagaaieratxi..",
    "@context": [
        "https://www.w3.org/ns/did/v1",
        "https://w3id.org/security/suites/ed25519-2020/v1",
        "https://w3id.org/security/suites/x25519-2020/v1"
    ],
    "verificationMethod": [...],
    "assertionMethod": ["did:p2p:bagaaieratxib#wtyb2xhyvxolbd.."],
    "authentication": ["did:p2p:bagaaieratxib#3txadadmtke6d.."],
    "keyAgreement": ["did:p2p:bagaaieratxib#cnzphk5djc3bt64.."]
}

Full example

{
    "id": "did:p2p:bagaaieratxin4o3iclo7ua3s3bbueds2uzfc5gi26mermevzb2etqliwjbla",
    "microledger": {
        "inception": {
            "keyType": "Ed25519VerificationKey2020",
            "nextKeyDigest": "by5gtwpufy4..",
            "recoveryKeyDigest": "bmb2cvioxfy65ej.."
        },
        "events": [
            {
                "payload": {
                    "previous": "bagaaieratxin4o3iclo7u..",
                    "signerKey": "by5gtwpufy4zfnog4j..",
                    "nextKeyDigest": "b2wvipekepehi..",
                    "change": {
                        "type": "SetDocument",
                        "value": "bdu3gqtjc6ks52.."
                    },
                    "timestamp": 1642418658
                },
                "proof": "bx6svqb6if5yaflgoumdff7j.."
            },
            {
                "payload": {
                    "previous": "bagaaieratxin4o3iclo7u..",
                    "signerKey": "by5gtwpufy4zfnog4j..",
                    "nextKeyDigest": "b2wvipekepehi..",
                    "change": {
                        "type": "SetProof",
                        "key": "bnnsxs",
                        "value": "bozqwy5lf"
                    },
                    "timestamp": 1642418658
                },
                "proof": "bwltjvobkxxq6.."
            },
            {
                "payload": {
                    "previous": "bagaaieratxin4o3iclo7u..",
                    "signerKey": "by5gtwpufy4zfnog4j..",
                    "nextKeyDigest": "b2wvipekepehi..",
                    "change": {
                        "type": "Recover",
                        "keyType": "Ed25519VerificationKey2020",
                        "recoveryKeyDigest": "bcut3s....."
                    },
                    "timestamp": 1642418658
                },
                "proof": "b3yo6vlymyn.."
            }
        ]
    },
    "document": {
        "@context": [
            "https://www.w3.org/ns/did/v1",
            "https://w3id.org/security/suites/ed25519-2020/v1",
            "https://w3id.org/security/suites/x25519-2020/v1"
        ],
        "id": "did:p2p:bagaaieratxin..",
        "controller": "did:p2p:bagaaieratxi..",
        "verificationMethod": [],
        "assertionMethod": [
            "did:p2p:bagaaieratxib#wtyb2xhyvxolbd.."
        ],
        "authentication": [
            "did:p2p:bagaaieratxib#3txadadmtke6d.."
        ],
        "keyAgreement": [
            "did:p2p:bagaaieratxib#cnzphk5djc3bt64.."
        ]
    }
}

Demo

Contributions

The idp2p protocol and implementations are both work in progress.

Contributions are most welcome.

License

Apache License 2.0

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