DIP-267 Provide a User Data mechanism for links to profiles (#277)

Problem
=======
#267 discusses the advantages of DSNP profile documents being
discoverable based on a user's identifier, rather than being temporal
data that must be externally tracked and indexed to be useful.

Solution
========
This proposal adds a new User Data type, `profileResources`, which is
currently defined for the Activity Content profile document type, but is
extensible to other document types that may need to be user-centric in
the future.
A profile resource is simply a link type (as an integer) and a CID as a
string plus byte length.
We define link type 1 for AC profiles.

This change assumes we are versioning for 1.3, but does not include
versioning updates, which are in other open PRs at this time.

Change summary:
---------------
- [ ] ~~Updated Spec Versions~~
- [x] Added definition for ProfileResource Avro type
- [x] Added entry in User Data page for `profileResource`
- [x] Updated navigation; added ProfileResource, moved Profile
announcement to "Migrated" section

---------

Co-authored-by: Wes Biggs <wes.biggs@amplica.io>

.spellcheckerdict.txt

@@ -8,6 +8,7 @@ CalVer
 CC0
 Changelog
 changeType
+(cid|CID)s?
 [Cc]odec('s)?
 contentHash
 cryptographic
@@ -16,17 +17,19 @@ CtxSharedSecretA
 CtxSharedSecretB
 CtxSharedSecretBob
 Curve25519
-decrypt
+decrypt(ed)?
 Delegator
 Deserialize
 Diffie-Hellman
+discoverability
 [Dd]iscoverable
 DSNP
 DSNP-compatible
 DSNP-referenced
 ECIES
 EdDSA
 [Ee]num(s)?
+encodings
 Ethereum
 Extrinsics
 fromId
@@ -43,6 +46,7 @@ JSON-LD
 keccak-256
 keyId
 keyType
+Kubo
 LibertyDSNP
 libsodium
 little-endian
@@ -68,6 +72,7 @@ Polkadot
 Poly1305
 pre-configured
 PRId([ABs])?
+ProfileResource
 [Pp]ublicKey
 repo
 RFC[1-9][0-9]*

pages/DSNP/Announcements.md

@@ -15,14 +15,16 @@ Each Announcement has an enumerated type for use when separating out a stream of
 | 2 | [Broadcast](Types/Broadcast.md) | a public post | YES | YES |
 | 3 | [Reply](Types/Reply.md) | a public response to a Broadcast | YES | YES |
 | 4 | [Reaction](Types/Reaction.md) | a public visual reply to a Broadcast | no | no |
-| 5 | [Profile](Types/Profile.md) | a profile | YES | no |
+| 5 | ~~[Profile](Types/Profile.md)~~<sup>c</sup> | ~~a profile~~ | ~~YES~~ | ~~no~~ |
 | 6 | [Update](Types/Update.md) | an update to content| YES | no |
 | 7 | ~~[Public Key](Types/PublicKey.md)~~<sup>b</sup> | ~~a public key for secure communication~~ | ~~no~~ | ~~no~~ |
 
 <sup>a</sup> Since DSNP version 1.2, social graph changes use [User Data](UserData.md) operations as described in the [Graph](Graph.md) section. 
 
 <sup>b</sup> Since DSNP version 1.3, public keys use [User Data](UserData.md) operations.
 
+<sup>c</sup> Since DSNP version 1.3, profile changes use [User Data](UserData.md) operations.
+
 ## Announcement Validation
 
 There is no guarantee that, at time of creation, a given Announcement will be from the `fromId` claimed in the Announcement.

pages/DSNP/Identifiers.md

@@ -49,11 +49,29 @@ Any [Announcement Types](Announcements.md#announcement-types) with a `fromId` an
 
 ### Example
 ```
-dsnp://78187493520/0x1234567890abcdef0123456789abcdef0123456789abcdef0123456789abcdef
+dsnp://78187493520/QmQNHNfHnbgJJ6nK4UPx2VtTUCafAKCbqZJ6ZRYUGjoeFj
 ```
 
 | part | value |
 | ---- | ----- |
 | Scheme | `dsnp://` |
 | User Id | `78187493520` |
-| Content Hash | `0x1234567890abcdef0123456789abcdef0123456789abcdef0123456789abcdef` |
+| Content Hash | `QmQNHNfHnbgJJ6nK4UPx2VtTUCafAKCbqZJ6ZRYUGjoeFj` |
+
+## DSNP CID
+
+A DSNP CID is a valid  [Content IDentifier](https://github.com/multiformats/cid) generated using the following parameters.
+
+### Supported CID Parameters
+
+The CID specification allows CIDs to be generated with a wide and ever-growing range of possible hashing algorithms, string encodings, and block sizes.
+In order for DSNP applications to interoperate, the required functionality is limited as follows:
+
+- CID version: MUST be version 1, in order to distinguish CIDs from simple multihash values in situations where either may be used
+- Hash algorithm: MUST be `sha2-256` or `blake2b-256`
+- Encoding: MUST be `base58btc` or `base32`
+- Codec: MUST be `dag-pb` for data 256*1024 bytes or longer; `raw` for data less than 256*1024 bytes
+- Chunking: Non-leaf nodes MUST be 256*1024 bytes
+
+The rationale for these options is to allow consuming applications to attempt to generate a matching CID from a byte stream for validation purposes without the need to reprocess the stream.
+These options are intentionally aligned to interoperate with the default output of the [Kubo](https://github.com/ipfs/kubo) IPFS command line utility when invoked as `ipfs add --cid-version=1 ...`.

pages/DSNP/Identity.md

@@ -29,18 +29,29 @@ An implementation MUST NOT allow the user to remove the only or last remaining c
 
 A user may choose to retire their Identifier at any time.
 Once an Identifier is retired, an implementation MAY remove all state data associated with that Identifier, provided that an indication that the Identifier is retired remains, so it may not be reused in the future.
-This means that all data previously sent from the Identifier, the keys associated with the Identifier, and the delegations (see next section) associated with the Identifier may be removed.
+This means that all data previously sent from the Identifier, the keys associated with the Identifier, any user data (see below) associated with the Identifier, and the delegations (see next section) associated with the Identifier may be removed.
 
 After an Identifier is retired, any existing or future [Announcements](Announcements.md) from the Identifier should be treated as if they have been [tombstoned](Types/Tombstone.md) (for Announcement Types that support tombstoning).
 A retired Identifier MUST NOT be allowed to act as a principal for any additional DSNP [Operations](Operations.md).
 
-### Delegation
+## Delegation
 
-* An owner MUST be able to delegate permission to announce on their behalf to other parties.
+* A user MUST be able to delegate and revoke permissions to other parties to submit each type of announcement or replace each type of user data on their behalf.
 * A user MUST be able to revoke delegated permissions.
-* Announcements from a delegate MUST be able to be verify which delegate made the specific Announcement.
+* Announcements and user data updates from a delegate MUST be able to be verified as to which delegate was responsible for the action.
 * Delegation revocation MUST NOT be retroactive.
 
+## Identity-Linked State Data
+
+DSNP identities can have linked [User Data](UserData.md), which, like the identifier and delegations, forms part of the shared state of the consensus system.
+As consensus system state storage is generally much more expensive than external data storage, shared state storage is only required for data considered critical for maintaining user agency and discoverability with low latency and high availability.
+
+User data is utilized for the following types of identity-linked data:
+* Public keys that can be used to encrypt data that can later be decrypted by the user or used to verify signatures on documents created by the user
+* [Social Graphs](Graph.md), both public and private (encrypted)
+* Links to [Profile documents](../ActivityContent/Types/Profile.md)
+
+
 ## Related Operations
 
 * [Create Identifier](Operations.md#create-identifier)
@@ -49,6 +60,8 @@ A retired Identifier MUST NOT be allowed to act as a principal for any additiona
 * [Revoke Delegation](Operations.md#revoke-delegation)
 * [Add Control Key](Operations.md#add-control-key)
 * [Remove Control Key](Operations.md#remove-control-key)
+* [Replace User Data](Operations.md#replace-user-data)
+* [Get User Data](Operations.md#get-user-data)
 
 ## Non-normative
 

pages/DSNP/Migrated.md

@@ -1,3 +1,4 @@
 # Migrated Announcements
 
-* [Graph Change](Types/GraphChange.md)
+* [Graph Change](Types/GraphChange.md) 
+* [Profile](Types/Profile.md) 

pages/DSNP/Types/ProfileResource.md

@@ -0,0 +1,56 @@
+# ProfileResource
+
+A profile-linked resource is represented by the ProfileResource object type.
+
+## Serialization
+
+ProfileResource object serialization MUST conform to the following [Avro](https://avro.apache.org) schema:
+
+```
+{
+    "namespace": "org.dsnp",
+    "name": "ProfileResource",
+    "type": "record",
+    "doc": "Profile-linked resource",
+    "fields": [
+        {
+            "name": "type",
+            "type": "int",
+            "doc": "Type of resource"
+        },
+        {
+            "name": "cid",
+            "type": "string",
+            "doc": "Content IDentifier of resource"
+        },
+        {
+            "name": "length",
+            "type": "int",
+            "doc": "Length of document in bytes"
+        }
+    ]
+}
+```
+
+## Generation
+
+### type
+
+- MUST be a supported DSNP profile-linked resource type.
+
+#### Supported Profile-Linked Resource Types
+
+| Value | Description | Specification | Content Type | DSNP Version Added |
+| --- | --- | --- | --- |
+| 1 | Activity Content Profile with DSNP extensions | [DSNP Profile](../../ActivityContent/Types/Profile.md) | `application/json` | 1.3 |
+
+All other document type values are reserved for future expansion.
+
+### cid
+
+- MUST be a valid [DSNP CID](../Identifiers.md#dsnp-cid]
+
+### length
+
+- MUST be a positive integer
+- MUST match the length in bytes of the document

pages/DSNP/UserData.md

@@ -21,6 +21,7 @@ DSNP implementations MUST support the following User Data Types:
 | <a name="private-connection-prids">`privateConnectionPRIds`</a> | 1.2 | NONE | NONE | [PRId](Types/PRId.md) |
 | <a name="key-agreement-public-keys">`keyAgreementPublicKeys`</a> | 1.3 | NONE | NONE | [PublicKey](Types/PublicKeyUserData.md) |
 | <a name="assertion-method-public-keys">`assertionMethodPublicKeys`</a> | 1.3 | NONE | NONE | [PublicKey](Types/PublicKeyUserData.md) |
+| <a name="profile-resources">`profileResources`</a> | 1.3 | NONE | NONE | [ProfileResource](Types/ProfileResource.md) |
 
 Data for each data type is initially formatted as a stream of Avro objects that should conform to the schema specified.
 A DSNP system MAY limit the number of objects allowed for a given user data type; if so, this MUST be documented.

pages/SUMMARY.md

@@ -9,17 +9,18 @@
       - [Graph Edge](DSNP/Types/GraphEdge.md)
       - [PRId](DSNP/Types/PRId.md)
       - [Public Key](DSNP/Types/PublicKeyUserData.md)
+      - [ProfileResource](DSNP/Types/ProfileResource.md)
     - [Batch Publications](DSNP/BatchPublications.md)
     - [Announcements](DSNP/Announcements.md)
         - [Tombstone](DSNP/Types/Tombstone.md)
         - [Broadcast](DSNP/Types/Broadcast.md)
         - [Reply](DSNP/Types/Reply.md)
         - [Reaction](DSNP/Types/Reaction.md)
-        - [Profile](DSNP/Types/Profile.md)
         - [Update](DSNP/Types/Update.md)
         - [Migrated Announcements](DSNP/Migrated.md)
             - [Graph Change](DSNP/Types/GraphChange.md)
             - [Public Key](DSNP/Types/PublicKey.md)
+            - [Profile](DSNP/Types/Profile.md)
     - [Operations](DSNP/Operations.md)
     - [State Change Records](DSNP/Records.md)
     - [Serializations](DSNP/Serializations.md)