NIP-66

Decimate

draft optional author:hendore

A destructive event with kind 10, the decimate event (from Latin decem, meaning "ten") will delete matching events stored on the receiving relay.

The content is not used and SHOULD be an empty string.

Relays SHOULD accept new events in the future from the same pubkey, this event only effects what is currently stored on the relay at the time it was published.

Relays MAY delete the events from their database or soft delete but they SHOULD NOT emit those events in the future if soft deleted.

Matching

Matches are based on event pubkey, relay tags and include/exclude tags.

A list of r tags will be used to prevent accidental deletion from a preffered relay. Any relays receiving this event that are not defined in the list of r tags would ignore the event.

Either an include or exclude tag must be provided but not both. The value of these tags contain a list of event kinds that should be taken into account when matching events to be removed.

Purpose

The purpose of this NIP is to provide a way for users to retain control over the relays that store and share their events. Over time, it's likely users would find a few small sets of relays they prefer to publish to and would like to remove any/all events previously stored on relays used in the past.

This NIP paves the way for more control over a users data with the possibility of event management clients appearing to migrate / cleanup old events when switching to new preferred relays.

Examples

Given we publish the events below to the following relays

wss://example.relay.io
wss://another-example.relay.io
wss://some-new.relay.io
wss://another-new.relay.io
wss://one-more.relay.io

Deleting everything except profile and preferred relay metadata

Any events stored on the two relays listed in the r tags would be deleted except for events with the kind 0 or 10002. The remaining 3 relays that received the event can safely ignore it.

{
  "pubkey": "...........",
  "kind": 10,
  "tags": [
    ["r", "wss://example.relay.io"],
    ["r", "wss://another-example.relay.io"],
    ["exclude", [0, 10002]]
  ],
  "content": "",
  ...other fields
}

Deleting only notes from a single relay

All of the users kind 1 events would be deleted on wss://one-more.relay.io the remaining 4 relays that received the event can safely ignore it.

{
  "pubkey": "...........",
  "kind": 10,
  "tags": [
    ["r", "wss://one-more.relay.io"],
    ["include", [1]]
  ],
  "content": "",
  ...other fields
}

Considerations

Some thought may need to go into rouge clients, in it's current state a bad acting client may sign and publish a decimate event to many relays. NIP26 if widely adopted could prevent this in the future if users only give clients enough power for what the client needs rather than their root keypair.

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