nips/22.md

NIP-22

Unacceptable Event created_at time

draft optional author:jeffthibault

Relays may support notifying clients that the event they published has an unacceptable created_at time. A relay will consider the created_at time unacceptable if the created_at time is more than [limit] before the event was received by the relay (in the past) OR if the created_at time is later than the time the event was received by the relay (in the future).

If a relay supports this NIP, the relay SHOULD send the client a NOTICE message saying the event was not stored because the created_at time was unacceptable.

Client Behavior

Clients SHOULD use the supported_nips field to learn if a relay supports event created_at time checks.

Motivation

The motivation for this NIP is to prevent clients from saying they published an event significantly earlier than they actually did or saying they published an event in the future.

The event created_at field is just a unix timestamp (integer) so one could set it to a time in the past or future. For example, the created_at field could be set to a time 10 years ago even though it was created today and it could still be a valid event. One could also set the created_at field to a time 10 years in the future and it could still be a valid event. This NIP aims to set a maximum amount of time elapsed between when an event was created and when it was actually published and prevent events from being from the future.

Relay Logic

if time.now - event.created_at > limit OR event.created_at > time.now:
  send NOTICE