relay-based event access-control with the ["-"] tag

70.md

@@ -0,0 +1,45 @@
+NIP-70
+======
+
+Protected Events
+----------------
+
+`draft` `optional`
+
+When the `"-"` tag is present, that means the event is "protected".
+
+A protected event is an event that can only be published to relays by its author. This is achieved by relays ensuring that the author is [authenticated](42.md) before publishing their own events or by just rejecting events with `["-"]` outright.
+
+The default behavior of a relay MUST be to reject any event that contains `["-"]`.
+
+Relays that want to accept such events MUST first require that the client perform the [NIP-42](https://github.com/nostr-protocol/nips/blob/master/42.md) `AUTH` flow and then check if the authenticated client has the same pubkey as the event being published and only accept the event in that case.
+
+## The tag
+
+The tag is a simple tag with a single item: `["-"]`. It may be added to any event.
+
+## Example flow
+
+- User `79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798` connects to relay `wss://example.com`:
+
+```jsonc
+/* client: */
+["EVENT",{"id":"cb8feca582979d91fe90455867b34dbf4d65e4b86e86b3c68c368ca9f9eef6f2","pubkey":"79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798","created_at":1707409439,"kind":1,"tags":[["-"]],"content":"hello members of the secret group","sig":"fa163f5cfb75d77d9b6269011872ee22b34fb48d23251e9879bb1e4ccbdd8aaaf4b6dc5f5084a65ef42c52fbcde8f3178bac3ba207de827ec513a6aa39fa684c"}]
+/* relay: */
+["AUTH", "<challenge>"]
+["OK", "cb8feca582979d91fe90455867b34dbf4d65e4b86e86b3c68c368ca9f9eef6f2", false, "auth-required: this event may only be published by its author"]
+/* client: */
+["AUTH", {}]
+["EVENT",{"id":"cb8feca582979d91fe90455867b34dbf4d65e4b86e86b3c68c368ca9f9eef6f2","pubkey":"79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798","created_at":1707409439,"kind":1,"tags":[["-"]],"content":"hello members of the secret group","sig":"fa163f5cfb75d77d9b6269011872ee22b34fb48d23251e9879bb1e4ccbdd8aaaf4b6dc5f5084a65ef42c52fbcde8f3178bac3ba207de827ec513a6aa39fa684c"}]
+["OK", "cb8feca582979d91fe90455867b34dbf4d65e4b86e86b3c68c368ca9f9eef6f2", true, ""]
+```
+
+## Why
+
+There are multiple circumstances in which it would be beneficial to prevent the unlimited spreading of an event through all relays imaginable and restrict some to only a certain demographic or to a semi-closed community relay. Even when the information is public it may make sense to keep it compartimentalized across different relays.
+
+It's also possible to create closed access feeds with this when the publisher has some relationship with the relay and trusts the relay to not release their published events to anyone.
+
+Even though it's ultimately impossible to restrict the spread of information on the internet (for example, one of the members of the closed group may want to take an event intended to be restricted and republish it to other relays), most relays would be happy to not facilitate the acts of these so-called "pirates", in respect to the original decision of the author and therefore gladly reject these republish acts if given the means to.
+
+This NIP gives these authors and relays the means to clearly signal when a given event is not intended to be republished by third parties.