The set of `pubkey` + `p` tags defines a chat room. If a new `p` tag is added or a current one is removed, a new room is created with clean message history.
An optional `subject` tag defines the current name/topic of the conversation. Any member can change the topic by simply submitting a new `subject` to an existing `pubkey` + `p`-tags room. There is no need to send `subject` in every message. The newest `subject` in the thread is the subject of the conversation.
Following [NIP-59](59.md), the **unsigned**`kind:14` chat message must be sealed (`kind:13`) and then gift-wrapped (`kind:1059`) to each receiver and the sender individually.
Clients MUST verify if pubkey of the `kind:13` is the same pubkey on the `kind:14`, otherwise any sender can impersonate others by simply changing the pubkey on `kind:14`.
Clients SHOULD randomize `created_at` in up to two days in the past in both the seal and the gift wrap to make sure grouping by `created_at` doesn't reveal any metadata.
The gift wrap's `p`-tag can be the receiver's main pubkey or an alias key created to receive DMs without exposing the receiver's identity.
Clients CAN offer disappearing messages by setting an `expiration` tag in the gift wrap of each receiver or by not generating a gift wrap to the sender's public key
Clients SHOULD publish kind `14` events to the `10050`-listed relays. If that is not found that indicates the user is not ready to receive messages under this NIP and clients shouldn't try.
1.**No Metadata Leak**: Participant identities, each message's real date and time, event kinds, and other event tags are all hidden from the public. Senders and receivers cannot be linked with public information alone.
2.**No Public Group Identifiers**: There is no public central queue, channel or otherwise converging identifier to correlate or count all messages in the same group.
3.**No Moderation**: There are no group admins: no invitations or bans.
4.**No Shared Secrets**: No secret must be known to all members that can leak or be mistakenly shared
5.**Fully Recoverable**: Messages can be fully recoverable by any client with the user's private key
6.**Optional Forward Secrecy**: Users and clients can opt-in for "disappearing messages".
7.**Uses Public Relays**: Messages can flow through public relays without loss of privacy. Private relays can increase privacy further, but they are not required.
8.**Cold Storage**: Users can unilaterally opt-in to sharing their messages with a separate key that is exclusive for DM backup and recovery.
The main limitation of this approach is having to send a separate encrypted event to each receiver. Group chats with more than 100 participants should find a more suitable messaging scheme.
Clients implementing this NIP should by default only connect to the set of relays found in their `kind:10050` list. From that they should be able to load all messages both sent and received as well as get new live updates, making it for a very simple and lightweight implementation that should be fast.
When sending a message to anyone, clients must then connect to the relays in the receiver's `kind:10050` and send the events there, but can disconnect right after unless more messages are expected to be sent (e.g. the chat tab is still selected). Clients should also send a copy of their outgoing messages to their own `kind:10050` relay set.
This example sends the message `Hola, que tal?` from `nsec1w8udu59ydjvedgs3yv5qccshcj8k05fh3l60k9x57asjrqdpa00qkmr89m` to `nsec12ywtkplvyq5t6twdqwwygavp5lm4fhuang89c943nf2z92eez43szvn4dt`.
