nips/00.md

NIP-XX

Access Control Upgrade

draft optional

This NIP defines how to upgrade a public event with the property of limiting access to itself.

Upgrading a Public Event

A public event (with no access control), such as of kind:1, must be published or updated with a full_event tag pointing to a kind:40042 event address.

It's data should be set to a warning that the event is private or to a preview version of the full event, in case the goal is to tease an user to pay for content, for example.

For example, a kind:1 event could have it's .content set to "You don't have access to this event." to be showed to users that don't have acces to the event or that are using a client that doesn't support this NIP. On the other hand, if the goal is to convince an user to pay for the full event, the .content could be set to a text excerpt like the following: "This is the first sentence of the full text. This text is trimmed to 5% of the character count of the full text..."

Taking the kind:1063 metadata event of an image as an example, it could had set its url tag to a blurred version of the image or simply use the .content (that according to NIP-94 means "caption") set to "You don't have access to this event".

Example:

{
  "kind": 1063,
  "tags": [
    ["full_event", "40042:<32-bytes lowercase hex of a pubkey>:abc", "<recommended relay URL, optional>"],
    ["url", "<string with PREVIEW url>"],
    ["dim", "800x600"]
  ],
  "content": "",
  ...
}

Full Event

A "Full Event" is of kind:40042. It has NIP-42 A tags the author can update at will with the pubkeys allowed to access it.

It uses the custom NIP-42 event serialization for events that require AUTH.

The .content and other tags aren't fixed. The structure depends on the kind of the public event it is protecting. For example, if it is protecting a kind:30023 event, it should have the structure defined on NIP-23.

Example:

{
  "kind": 40042,
  "pubkey": "<author_pubkey>",
  "tags": [
    ["d", "<random>"],
    ["A", "<author_pubkey>"], // important to keep author access right
    ["A", "<buyer_1_pubkey>"],
    ["A", "<buyer_2_pubkey>"],
    ["url", "https://some.place/file.webp"],
    ["dim", "800x600"]
  ],
  "content": "Happy New Year, my dear supporters!!",
  ...
}

Requesting the Event

The client is expected to initially request the public event. For example, a microblogging client will request kind:1 events as usual.

If one of these events includes a full_event tag, supporting clients should request it with a filter that includes a #A filter key set to the client's user pubkey. Clients that don't understand this NIP, however, will show the kind:1 .content as usual and ignore the full_event tag.

If the user has rights to access the full event, the relay will send it after the NIP-42 authentication flow.

Example of how to request the full event:

["REQ", "sub_id", { "kinds": [40042], "authors": ["abc"], #d: ["xyz"], "#A": ["<client's user pubkey>"], "limit": 1 }]