From 752bb5019eeffa862a5ffeb02471987ec94b1ded Mon Sep 17 00:00:00 2001
From: Will Pfleger <pfleger.will@gmail.com>
Date: Tue, 23 Jun 2026 21:16:38 -0400
Subject: [PATCH] refactor(desktop): move DM peer crypto off the main thread
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The nip44_encrypt_to_peer / nip44_decrypt_from_peer commands ran the
CPU-bound NIP-44 encrypt/decrypt synchronously while holding the keys
lock on the main thread. #1222 already moved the equivalent *_self
commands off-thread via async + spawn_blocking; these DM commands
predate that change and were left on the asymmetric path. Mirror the
*_self template so the hottest DM paths (encrypt-on-send,
decrypt-on-render) no longer block the main thread. Callers are
unchanged — both already await through invokeTauri.

Co-authored-by: Will Pfleger <pfleger.will@gmail.com>
Signed-off-by: Will Pfleger <pfleger.will@gmail.com>
---
 desktop/src-tauri/src/commands/identity.rs | 26 +++++++++++++++-------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/desktop/src-tauri/src/commands/identity.rs b/desktop/src-tauri/src/commands/identity.rs
index eb853835e..f4dd796e5 100644
--- a/desktop/src-tauri/src/commands/identity.rs
+++ b/desktop/src-tauri/src/commands/identity.rs
@@ -274,16 +274,21 @@ pub async fn nip44_decrypt_from_self(
 /// Rust backend — the frontend only sends plaintext + peer pubkey and gets the
 /// ciphertext back to embed in the kind:9 it signs. Used for DM encrypt-on-send.
 #[tauri::command]
-pub fn nip44_encrypt_to_peer(
+pub async fn nip44_encrypt_to_peer(
     peer_pubkey: String,
     plaintext: String,
     state: State<'_, AppState>,
 ) -> Result<String, String> {
     let peer =
         PublicKey::from_hex(peer_pubkey.trim()).map_err(|e| format!("invalid peer pubkey: {e}"))?;
-    let keys = state.keys.lock().map_err(|e| e.to_string())?;
-    nip44::encrypt(keys.secret_key(), &peer, &plaintext, nip44::Version::V2)
-        .map_err(|e| format!("nip44 encrypt failed: {e}"))
+    let keys = state.keys.lock().map_err(|e| e.to_string())?.clone();
+
+    tauri::async_runtime::spawn_blocking(move || {
+        nip44::encrypt(keys.secret_key(), &peer, &plaintext, nip44::Version::V2)
+            .map_err(|e| format!("nip44 encrypt failed: {e}"))
+    })
+    .await
+    .map_err(|e| format!("spawn_blocking failed: {e}"))?
 }
 
 /// NIP-44 v2 decrypt DM `ciphertext` from a peer. The peer pubkey is the other
@@ -292,14 +297,19 @@ pub fn nip44_encrypt_to_peer(
 /// key decrypts both). Used for DM decrypt-on-render; on failure the frontend
 /// shows the mixed-version placeholder rather than blank or garbled content.
 #[tauri::command]
-pub fn nip44_decrypt_from_peer(
+pub async fn nip44_decrypt_from_peer(
     peer_pubkey: String,
     ciphertext: String,
     state: State<'_, AppState>,
 ) -> Result<String, String> {
     let peer =
         PublicKey::from_hex(peer_pubkey.trim()).map_err(|e| format!("invalid peer pubkey: {e}"))?;
-    let keys = state.keys.lock().map_err(|e| e.to_string())?;
-    nip44::decrypt(keys.secret_key(), &peer, &ciphertext)
-        .map_err(|e| format!("nip44 decrypt failed: {e}"))
+    let keys = state.keys.lock().map_err(|e| e.to_string())?.clone();
+
+    tauri::async_runtime::spawn_blocking(move || {
+        nip44::decrypt(keys.secret_key(), &peer, &ciphertext)
+            .map_err(|e| format!("nip44 decrypt failed: {e}"))
+    })
+    .await
+    .map_err(|e| format!("spawn_blocking failed: {e}"))?
 }