NIP-59: Add ephemeral gift wrap event kind (21059) (#2245)

59.md

@@ -72,6 +72,28 @@ needed to route the event to its intended recipient, including the recipient's `
 }
 ```
 
+### 4. Ephemeral Gift Wrap Event Kind
+
+An ephemeral gift wrap is a `kind:21059` event. It has the same structure as `kind:1059` but follows ephemeral event
+semantics (relays MUST NOT store it).
+
+```json
+{
+  "id": "<id>",
+  "pubkey": "<random, one-time-use pubkey>",
+  "content": "<encrypted kind 13>",
+  "kind": 21059,
+  "created_at": 1686840217,
+  "tags": [["p", "<recipient pubkey>"]],
+  "sig": "<random, one-time-use pubkey signature>"
+}
+```
+
+`kind:1059` is intended for regular direct messages and asynchronous communication where message persistence
+and offline delivery are expected, such as in NIP-17. `kind:21059` is intended for real-time applications
+that do not require asynchronous operations and where messages are only relevant to currently connected
+recipients, such as live chat or real-time gaming.
+
 ## Encrypting Payloads
 
 Encryption is done following [NIP-44](44.md) on the JSON-encoded event. Place the encryption payload in the `.content`
@@ -103,7 +125,7 @@ AUTH, and refuse to serve wrapped events to non-recipients.
 
 When adding expiration tags to both `seal` and `gift wrap` layers, implementations SHOULD use independent random timestamps for each layer. Using different `created_at` values increases timing variance and helps protect against metadata correlation attacks.
 
-Since signing keys are random, relays SHOULD delete `kind 1059` events whose p-tag matches the signer of
+Since signing keys are random, relays SHOULD delete `kind:1059` events whose p-tag matches the signer of
 [NIP-09](09.md) deletions or [NIP-62](62.md) vanish requests.
 
 ## An Example
@@ -171,7 +193,7 @@ Sign the `gift wrap` using the random key generated in the previous step.
 
 ### 4. Broadcast Selectively
 
-Broadcast the `kind 1059` event to the recipient's relays only. Delete all the other events.
+Broadcast the `kind:1059` or `kind:21059` event to the recipient's relays only. Delete all the other events.
 
 ## Code Samples
 
@@ -238,6 +260,20 @@ const createWrap = (event: Event, recipientPublicKey: string) => {
   ) as Event
 }
 
+const createEphemeralWrap = (event: Event, recipientPublicKey: string) => {
+  const randomKey = generateSecretKey()
+
+  return finalizeEvent(
+    {
+      kind: 21059,
+      content: nip44Encrypt(event, randomKey, recipientPublicKey),
+      created_at: randomNow(),
+      tags: [["p", recipientPublicKey]],
+    },
+    randomKey
+  ) as Event
+}
+
 // Test case using the above example
 const senderPrivateKey = nip19.decode(`nsec1p0ht6p3wepe47sjrgesyn4m50m6avk2waqudu9rl324cg2c4ufesyp6rdg`).data
 const recipientPrivateKey = nip19.decode(`nsec1uyyrnx7cgfp40fcskcr2urqnzekc20fj0er6de0q8qvhx34ahazsvs9p36`).data