nips/26.md

NIP: 26

Delegated Event Signing

draft optional author:markharding author:minds

This NIP defines how events can be delegated so that they can be signed by other keypairs.

Another application of this proposal is to abstract away the use of the 'root' keypairs when interacting with clients. For example, a user could generate new keypairs for each client they wish to use and authorize those keypairs to generate events on behalf of their root pubkey, where the root keypair is stored in cold storage.

Introducing the 'delegation' tag

This NIP introduces a new tag: delegation which is formatted as follows:

[
  "delegation",
  <pubkey of the delegator>,
  <conditions query string>,
  <64-bytes schnorr signature of the sha256 hash of the delegation token>
]

Delegation Token

The delegation token should be a 64-byte Schnorr signature of the sha256 hash of the following string:

nostr:delegation:<pubkey of publisher (delegatee)>:<conditions query string>

Example

# Delegator:
privkey: ee35e8bb71131c02c1d7e73231daa48e9953d329a4b701f7133c8f46dd21139c
pubkey:  8e0d3d3eb2881ec137a11debe736a9086715a8c8beeeda615780064d68bc25dd

# Delegatee:
privkey: 777e4f60b4aa87937e13acc84f7abcc3c93cc035cb4c1e9f7a9086dd78fffce1
pubkey:  477318cfb5427b9cfc66a9fa376150c1ddbc62115ae27cef72417eb959691396

Delegation string to grant note publishing authorization to the delegatee (477318cf) for the next 30 days.

nostr:delegation:477318cfb5427b9cfc66a9fa376150c1ddbc62115ae27cef72417eb959691396:kind=1&created_at<1675721885

The delegator (8e0d3d3e) then signs the above delegation string, the result of which is the delegation token:

cbc49c65fe04a3181d72fb5a9f1c627e329d5f45d300a2dfed1c3e788b7834dad48a6d27d8e244af39c77381334ede97d4fd15abe80f35fda695fd9bd732aa1e

The delegatee (477318cf) can now construct an event on behalf of the delegator (8e0d3d3e). The delegatee then signs the event with its own private key and publishes.

{
  "id": "ac4c71e69c39b1bd605de812543ebfaf81d5af365354f061d48981fb61e00b8a",
  "pubkey": "477318cfb5427b9cfc66a9fa376150c1ddbc62115ae27cef72417eb959691396",
  "created_at": 1673129661,
  "kind": 1,
  "tags": [
    [
      "delegation",
      "8e0d3d3eb2881ec137a11debe736a9086715a8c8beeeda615780064d68bc25dd",
      "kind=1&created_at<1675721813",
      "cbc49c65fe04a3181d72fb5a9f1c627e329d5f45d300a2dfed1c3e788b7834dad48a6d27d8e244af39c77381334ede97d4fd15abe80f35fda695fd9bd732aa1e"
    ]
  ],
  "content": "Hello, world!",
  "sig": "55ed9a78d6449b8c189b6dbc34bc4bcd34dcc79e6da6c9078268fe3d7c0cbe62b1b907ffb76ba591e83895b1329bf2e6e16f3b0cd5827272e420d419c6f0f0b5"
}

The event should be considered a valid delegation if the conditions are satisfied (kind=1 and created_at<1675721813 in this example) and, upon validation of the delegation token, are found to be unchanged from the conditions in the original delegation string.

Clients should display the delegated note as if it was published directly by the delegator (8e0d3d3e).

Relay & Client Querying Support

Relays should answer requests such as ["REQ", "", {"authors": ["A"]}] by querying both the pubkey and delegation tags [1] value.