Support DID-based actor identifiers

[troyronda]

Enable Orb to support DID-based actor identifiers (e.g., did:web:example).

Supporting DID-based actors allows the actor response to look like:

{
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    "https://w3id.org/activityanchors/v1"
  ],
  "id": "did:web:alice.example.com:services:anchor,
  "type": "Service",
  "inbox": "https://alice.example.com/services/anchor/inbox",
  "outbox": "https://alice.example.com/services/anchor/outbox",
  "followers": "https://alice.example.com/services/anchor/followers",
  "following": "https://alice.example.com/services/anchor/following",
  "witnesses": "https://alice.example.com/services/anchor/witnesses",
  "witnessing": "https://alice.example.com/services/anchor/witnessing",
  "likes": "https://alice.example.com/services/anchor/likes",
  "liked": "https://alice.example.com/services/anchor/liked",
  "shares": "https://alice.example.com/services/anchor/shares"
}

Supporting DID-based actors allows messages to look like:

{
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    "https://w3id.org/activityanchors/v1"
  ],
  "id": "did:web:sally.example.com:services:anchor/activities/bafkreiatkubvbkdidscmqynkyls3iqawdqvthi7e6mbky2amuw3inxsi3y",
  "type": "Create",
  "actor": "did:web:sally.example.com:services:anchor",
  "to": [
    "did:web:sally.example.com:services:anchor/followers",
    "https://www.w3.org/ns/activitystreams#Public"
  ],
  "published": "2021-01-27T09:30:10Z",
  "object": {
    "type": "AnchorEvent",
    "attributedTo": "did:web:example.domain1.com:services:example",
    "index": "hl:uEiCF5Mr8n7NPsAGenkNIoY0tJtnqDUWMk_XdYpgOm5yNnA",
    "parent": "hl:uEiAL-T2TdNkqL5gRIX8BZvrXESPOzoIYy98YUBxc5xAG0w:uoQ-BeEJpcGZzOi8vYmFma3JlaWFsN2U2emc1Z3pmaXh6cWVqYnA0YXduNnd4Y2VyNDV0dWNkZGY1NmdjcWRyb29vZWFnMm0",
    "published": "2021-10-29T18:06:34.554883376Z",
    "url": "hl:uEiAyUitoMn-ujmlFC6DBW2AlWabxGfVpGw0b3ymcqwzSHQ:uoQ-BeEJpcGZzOi8vYmFma3JlaWJza2l2d3FtdDd2Mmhnc3JpbHVkYXZ3eWJmbGd0cGNncHZuZW5xMmc2N2Znb2t3ZGdzZHU",
    "attachment": [...]  
  }
}

[fqutishat]

#1335 duplicate

[bstasyszyn]

Adding new startup parameter:

--service-id:

The ID of the ActivityPub service. By default, the ID is composed of the external endpoint appended with /services/orb.
For example, if external-endpoint is set to https://alice.example.com then the service ID will
be https://alice.example.com/services/orb. The value may be set to a different path, e.g.
https://alice.example.com/services/anchor, or it can be set to a DID, e.g. did:web:alice.example.com:services:anchor.

If service-id is set to did:web:alice.example.com:services:anchor then the ActivityPub service (actor) looks like this:

{
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    "https://w3id.org/security/v1",
    "https://w3id.org/activityanchors/v1"
  ],
  "id": "did:web:alice.example.com:services:anchor",
  "publicKey": "did:web:alice.example.com:services:anchor#MrWUYMOS4ZGF7LCBVSr8njn98OvG70XaLV31EDFhBH0",
  "followers": "https://alice.example.com/services/anchor/followers",
  "following": "https://alice.example.com/services/anchor/following",
  "inbox": "https://alice.example.com/services/anchor/inbox",
  "liked": "https://alice.example.com/services/anchor/liked",
  "likes": "https://alice.example.com/services/anchor/likes",
  "outbox": "https://alice.example.com/services/anchor/outbox",
  "shares": "https://alice.example.com/services/anchor/shares",
  "type": "Service",
  "witnesses": "https://alice.example.com/services/anchor/witnesses",
  "witnessing": "https://alice.example.com/services/anchor/witnessing"
}

The service's DID document is resolved using a VDR (currently only did:web is supported so the document would be at https://alice.example.com/services/anchor/did.json):

{
  "@context": [
    "https://w3id.org/did/v1",
    "https://identity.foundation/.well-known/did-configuration/v1"
  ],
  "id": "did:web:alice.example.com:services:anchor",
  "verificationMethod": [
    {
      "controller": "did:web:alice.example.com:services:anchor",
      "id": "did:web:alice.example.com:services:anchor#MrWUYMOS4ZGF7LCBVSr8njn98OvG70XaLV31EDFhBH0",
      "publicKeyMultibase": "z7a7SJkF8LTqGACTxB8r86i2btE7y8qrPnGuCe3M9vk8f",
      "type": "Ed25519VerificationKey2020"
    }
  ],
  "service": [
    {
      "id": "did:web:alice.example.com:services:anchor#activity-pub",
      "serviceEndpoint": "https://alice.example.com",
      "type": "LinkedDomains"
    }
  ]
}

An activity would look like this:

{
  "@context": "https://www.w3.org/ns/activitystreams",
  "actor": "did:web:alice.example.com:services:anchor",
  "id": "https://alice.example.com/services/anchor/activities/3dd6c5bf-dc7c-4743-87b2-12d303f0ecaf",
  "object": {
    "@context": "https://w3id.org/activityanchors/v1",
    "object": {
      "linkset": [
        {
          "anchor": "hl:uEiAsmhY5seUU6LNsy30iJEjM-urZ4g_EPylBeXUTlzK33A",
          "author": "did:web:alice.example.com:services:anchor",
          "original": [
            {
              "href": "data:application/json,%7B%22linkset%22%3A%5B%7B%22anchor%22%3A%22hl%3AuEiDRfrx2UAy6wydaXceJL9hlpFQwTTuP_RIS5zm7J9sr2Q%22%2C%22author%22%3A%22did%3Aweb%3Aalice.example.com%3Aservices%3Aanchor%22%2C%22item%22%3A%5B%7B%22href%22%3A%22did%3Aorb%3AuAAA%3AEiDvfNx40DmnAE9tKw6eWue8OiWPh5668PvnyfcHQtr5sQ%22%7D%2C%7B%22href%22%3A%22did%3Aorb%3AuAAA%3AEiCgK6K4eVoW2vYINhGDYyUsaFQh0Xq2GeQQ6No7sXrezg%22%7D%2C%7B%22href%22%3A%22did%3Aorb%3AuAAA%3AEiAI60PiHNKAX7zGRe10UOPIfl5vabGYAkzOSF8KLgzmmg%22%7D%2C%7B%22href%22%3A%22did%3Aorb%3AuAAA%3AEiCgNvbqlq5yxQGrM6ipv6iMDLhwYmlDBZO1f60mfTnLaA%22%7D%2C%7B%22href%22%3A%22did%3Aorb%3AuAAA%3AEiBCHij5TOiT_D1COIdMGbBbIAJJ7PSt_aCWqv7BXFGpxQ%22%7D%2C%7B%22href%22%3A%22did%3Aorb%3AuAAA%3AEiBkfnunulwm2oj9_PZXtrBxWFclC6Z64Ou2rX5sGM-D_A%22%7D%2C%7B%22href%22%3A%22did%3Aorb%3AuAAA%3AEiBxxIu6yc1aFlCvV5rbjSbJ-qFWLLwxKPBstDyLMrhlNA%22%7D%2C%7B%22href%22%3A%22did%3Aorb%3AuAAA%3AEiCUipZOgwqREWpmRtln44hWDQhENOOPzX5ByukeYV5eLQ%22%7D%2C%7B%22href%22%3A%22did%3Aorb%3AuAAA%3AEiDk4OAYEyC3iQEqJcNxu6ljG7o5PayR-vugrtB27e_0KA%22%7D%2C%7B%22href%22%3A%22did%3Aorb%3AuAAA%3AEiDY8i8w9v7yFb6VmcKvoxNZ7X_VjWfGuSN-QLH6crHnWg%22%7D%5D%2C%22profile%22%3A%22https%3A%2F%2Fw3id.org%2Forb%23v0%22%7D%5D%7D",
              "type": "application/linkset+json"
            }
          ],
          "profile": "https://w3id.org/orb#v0",
          "related": [
            {
              "href": "data:application/json,%7B%22linkset%22%3A%5B%7B%22anchor%22%3A%22hl%3AuEiAsmhY5seUU6LNsy30iJEjM-urZ4g_EPylBeXUTlzK33A%22%2C%22profile%22%3A%22https%3A%2F%2Fw3id.org%2Forb%23v0%22%2C%22via%22%3A%5B%7B%22href%22%3A%22hl%3AuEiDRfrx2UAy6wydaXceJL9hlpFQwTTuP_RIS5zm7J9sr2Q%3AuoQ-BeEtodHRwczovL29yYi5kb21haW4yLmNvbS9jYXMvdUVpRFJmcngyVUF5Nnd5ZGFYY2VKTDlobHBGUXdUVHVQX1JJUzV6bTdKOXNyMlE%22%7D%5D%7D%5D%7D",
              "type": "application/linkset+json"
            }
          ],
          "replies": [
            {
              "href": "data:application/json,%7B%22%40context%22%3A%5B%22https%3A%2F%2Fwww.w3.org%2F2018%2Fcredentials%2Fv1%22%2C%22https%3A%2F%2Fw3id.org%2Factivityanchors%2Fv1%22%2C%22https%3A%2F%2Fw3id.org%2Fsecurity%2Fsuites%2Fjws-2020%2Fv1%22%2C%22https%3A%2F%2Fw3id.org%2Fsecurity%2Fsuites%2Fed25519-2020%2Fv1%22%5D%2C%22credentialSubject%22%3A%7B%22anchor%22%3A%22hl%3AuEiDRfrx2UAy6wydaXceJL9hlpFQwTTuP_RIS5zm7J9sr2Q%22%2C%22id%22%3A%22hl%3AuEiAsmhY5seUU6LNsy30iJEjM-urZ4g_EPylBeXUTlzK33A%22%2C%22profile%22%3A%22https%3A%2F%2Fw3id.org%2Forb%23v0%22%7D%2C%22id%22%3A%22https%3A%2F%2Falice.example.com%2Fvc%2F63384454-28f5-4dd9-9833-b7f79d9087a9%22%2C%22issuanceDate%22%3A%222022-08-09T14%3A16%3A17.653656394Z%22%2C%22issuer%22%3A%22https%3A%2F%2Falice.example.com%22%2C%22proof%22%3A%5B%7B%22created%22%3A%222022-08-09T14%3A16%3A17.656966342Z%22%2C%22domain%22%3A%22https%3A%2F%2Falice.example.com%22%2C%22proofPurpose%22%3A%22assertionMethod%22%2C%22proofValue%22%3A%22z4H9r9tgoSDVczeC5WSig5Mp4ASojXuzQJ9JTqm78GXKKpKUx2ETQSf1TUXLYU84Uq36Y6SaPzon4AstwqxyYRFRv%22%2C%22type%22%3A%22Ed25519Signature2020%22%2C%22verificationMethod%22%3A%22did%3Aweb%3Aalice.example.com%23m0lkGe6apkR_uzrcBHsttLf-cMgCS-Z4_27Qt5kyRG0%22%7D%2C%7B%22created%22%3A%222022-08-09T14%3A16%3A17.824Z%22%2C%22domain%22%3A%22http%3A%2F%2Forb.vct%3A8077%2Fmaple2020%22%2C%22proofPurpose%22%3A%22assertionMethod%22%2C%22proofValue%22%3A%22z5fBV9Dwac2c3rgg5adjpvWpWM57QuK5zh5FQXsn2Jr3bZyTd3G5ACwN23hiBUHFunJC73F28wg9AdYmXfzdHVjcJ%22%2C%22type%22%3A%22Ed25519Signature2020%22%2C%22verificationMethod%22%3A%22did%3Aweb%3Aorb.domain1.com%23ipyFbnxMIbWJME8K1uvIp-UdrdVpyuQ9QjCCgnHHjFg%22%7D%5D%2C%22type%22%3A%5B%22VerifiableCredential%22%2C%22AnchorCredential%22%5D%7D",
              "type": "application/ld+json"
            }
          ]
        }
      ]
    },
    "type": "AnchorEvent",
    "url": "hl:uEiCP980v2AZbTgRmebFolD48LhE4u-yXzOoISRUJkUjToQ:uoQ-BeEtodHRwczovL29yYi5kb21haW4yLmNvbS9jYXMvdUVpQ1A5ODB2MkFaYlRnUm1lYkZvbEQ0OExoRTR1LXlYek9vSVNSVUprVWpUb1E"
  },
  "published": "2022-08-09T14:16:18.013015949Z",
  "to": [
    "https://alice.example.com/services/anchor/followers",
    "https://www.w3.org/ns/activitystreams#Public"
  ],
  "type": "Create"
}

[troyronda]

FYI @talltree @brentzundel ^^^

[talltree]

@troyronda Looks good. What are our plans (if any) to support did:orb DIDs?