# XXX: DID:Indy Method

- Author
- Start Date: 2020-02-05

## Status
- Status: [PROPOSED](/README.md#hipe-lifecycle)
- Status Date: 2021-09-02
- Status Note:

## Summary

This HIPE describes the implementation of the did:indy concerning indy-node and indy-vdr according to the did:indy specification.
For motivation and more information please refer to the did:indy specification.

## Transaction format

- Needs new protocol version
-

## Indy Node / Plenum

## Indy VDR API

## Reference

## Drawbacks

## Rationale and alternatives

### Get specific version

https://github.com/hyperledger/indy-node/blob/master/docs/source/transactions.md#common-structure

{
    "ver": <...>,
    "txn": {
        ...
    },
    "txnMetadata": {
        "txnTime": <...>,
        "seqNo": <...>,
        "txnId": <...>
    },
    "reqSignature": {
       ...
    }
}

## Indy Node and Indy Plenum
### Write NYM

We need to adapt the schema of a write nym operation to include the optional `diddoccontent` attribut. The schema definition is part of [Plenum](https://github.com/hyperledger/indy-plenum/blob/5960118788c1a580cd271c50b920ac15b1497495/plenum/common/messages/client_request.py#L55)

Should we adapt the existing class

class ClientNYMOperation(MessageValidator):
    schema = (
        (TXN_TYPE, ConstantField(NYM)),
        (ALIAS, LimitedLengthStringField(max_length=ALIAS_FIELD_LIMIT, optional=True)),
        (VERKEY, VerkeyField(optional=True, nullable=True)),
        (TARGET_NYM, DestNymField()),
        (ROLE, RoleField(optional=True)),
        (DIDDOC_CONTENT, JsonField(max_length=JSON_FIELD_LIMIT(optional=True)),
        
    )

or add another class?

class ClientNYMOperationV2(MessageValidator):

I don't see a reason currently to add another class.

`JSON_FIELD_LIMIT` is used for the raw content of an ATTRIB tx and is set [here](https://github.com/hyperledger/indy-plenum/blob/f812a72197bc0740d4c6b75b796beff8f88c73f9/plenum/config.py#L316) to 5*1024

It seems that we don't need to adapt the [`update_state` function](https://github.com/hyperledger/indy-node/blob/master/indy_node/server/request_handlers/domain_req_handlers/nym_handler.py)

An open question would be if store the diddoccontent directly or use dedicated store as is done in the attrib case.

#### Validation

### Get NYM

No changes required?

Do we need new type/schemas of new version?

### GET DIDdoc by timestamp

We can roughly follow the process outlined in RevocRegEntry

1. Define get nym request and handler with additional timestamp [New schema](https://github.com/hyperledger/indy-node/blob/78bb325121be212f4dc729998d713dbbcde78bee/indy_common/types.py#L67) with ` (TIMESTAMP, IntegerField(optional=True))`and [enhanced logic](https://github.com/hyperledger/indy-node/blob/78bb325121be212f4dc729998d713dbbcde78bee/indy_node/server/request_handlers/read_req_handlers/get_nym_handler.py#L17) to do the following
3. Use `NymHandler.make_state_path_for_nym(nym)` as defined [here](https://github.com/hyperledger/indy-node/blob/78bb325121be212f4dc729998d713dbbcde78bee/indy_common/state/domain.py#L33)
4. Implement `get_nym_by_timestamp(timestamp, path_to_nym_entry)` similar to [_get_reg_entry_by_timestamp(self, timestamp, path_to_reg_entry)](https://github.com/hyperledger/indy-node/blob/78bb325121be212f4dc729998d713dbbcde78bee/indy_node/server/request_handlers/read_req_handlers/get_revoc_reg_delta_handler.py#L128). More about timestamp storage can be found [here](https://hyperledger-indy.readthedocs.io/projects/plenum/en/latest/storage.html#timestamp-storage)

### Get DIDdoc by version (==seqNo)

There seems to be no direct mapping between seqNo and state. Hence, I see the following options:

1. Introduce a new mapping `seqNo -> state` and add an optional seqNo attribute to the get nym request.
2. Use `GET_TXN(seqId)` internally, use `state_root_hash` which is part of the `state_proof` block to `get_value_from_state`. (Not sure if this the correct state root ([More info](https://github.com/hyperledger/indy-plenum/blob/5960118788c1a580cd271c50b920ac15b1497495/plenum/server/request_handlers/get_txn_handler.py#L43)))
2. Use `GET_TXN(seqId)` internally, get the timestamp from this TX and use `get_nym_by_timestamp`

### Noteworthy

- NYM tx is defined in [Plenum](https://github.com/hyperledger/indy-plenum/blob/master/plenum/common/transactions.py) not indy node

- There's a cache implementation to get verkey/role of a given nym https://github.com/hyperledger/indy-node/blob/master/indy_node/persistence/idr_cache.py

- There's a dedicated attribute (key-value) store. Only hashes are stored in the ledger. See https://github.com/hyperledger/indy-node/blob/78bb325121be212f4dc729998d713dbbcde78bee/indy_node/server/node.py#L252 However, this seems not to be used ?!

- There is already observer related code in [Plenum](https://github.com/hyperledger/indy-plenum/tree/f812a72197bc0740d4c6b75b796beff8f88c73f9/plenum/server/observer)

## Interesting Sources

- Talk: [Understanding the Hyperledger Indy Distributed Ledger - Alexander Shcherbakov, Evernym
](https://www.youtube.com/watch?v=ncdvaJrOm_Q)[Slides](https://de.slideshare.net/SSIMeetup/the-hyperledger-indy-public-blockchain-node)

- [How storage works](https://github.com/hyperledger/indy-plenum/blob/master/docs/source/storage.md)

## ToDos and Open Questions

-[ ] Update Transactions documentation
-[x] How is get revocation registry state implemented?
- https://github.com/hyperledger/indy-node/blob/78bb325121be212f4dc729998d713dbbcde78bee/indy_node/server/request_handlers/read_req_handlers/get_revoc_reg_delta_handler.py#L128
-[ ] Check how TAA request deals with (protocol) version update
-[ ] Do we need to add diddoccontent [here](https://github.com/hyperledger/indy-node/blob/master/indy_common/txn_util.py)
-[ ] What's static and dynamic validation in request handlers?

/indy_common/constants.py Line 104 allOpKeys add diddoccontent ?

* What's the Identity class? Where is used? Do we need to change it?
https://github.com/hyperledger/indy-node/blob/master/indy_common/identity.py

- Plenum DidIdentity https://github.com/hyperledger/indy-plenum/blob/master/plenum/common/signer_did.py

* Do we need to register new handlers?

indy_node/test/nym_txn/test_nym_resend.py::test_nym_send_twice FAILED [ 98%]
indy_node/test/nym_txn/test_nym_resend.py::test_nym_resend FAILED [ 98%]
indy_node/test/nym_txn/test_send_nym_validation.py::testSendNymSucceedsForUuidIdentifierAnsdk_pool_handlemittedVerkey FAILED [ 98%]