feat: show names with a lock for DMs using PKC

app/src/main/java/com/geeksville/mesh/DataPacket.kt

@@ -167,6 +167,9 @@ data class DataPacket(
         /// special broadcast address
         const val NODENUM_BROADCAST = (0xffffffff).toInt()
 
+        // Public-key cryptography (PKC) channel index
+        const val PKC_CHANNEL_INDEX = 8
+
         fun nodeNumToDefaultId(n: Int): String = "!%08x".format(n)
         fun idToDefaultNodeNum(id: String?): Int? = id?.toLong(16)?.toInt()
 

app/src/main/java/com/geeksville/mesh/service/MeshService.kt

@@ -533,7 +533,7 @@ class MeshService : Service(), Logging {
                 dataType = data.portnumValue,
                 bytes = data.payload.toByteArray(),
                 hopLimit = packet.hopLimit,
-                channel = packet.channel,
+                channel = if (packet.pkiEncrypted) DataPacket.PKC_CHANNEL_INDEX else packet.channel,
             )
         }
     }

app/src/main/java/com/geeksville/mesh/ui/MessagesFragment.kt

@@ -22,6 +22,7 @@ import androidx.lifecycle.asLiveData
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.lifecycleScope
 import androidx.lifecycle.repeatOnLifecycle
+import com.geeksville.mesh.DataPacket
 import com.geeksville.mesh.android.Logging
 import com.geeksville.mesh.R
 import com.geeksville.mesh.database.entity.QuickChatAction
@@ -121,10 +122,12 @@ class MessagesFragment : Fragment(), Logging {
         contactKey = arguments?.getString("contactKey").toString()
         val contactName = arguments?.getString("contactName").toString()
         binding.toolbar.title = contactName
-        if (contactKey[1] == '!') {
+        val channelNumber = contactKey[0].digitToIntOrNull()
+        if (channelNumber == DataPacket.PKC_CHANNEL_INDEX) {
+            binding.toolbar.title = "$contactName🔒"
+        } else if (channelNumber != null && contactKey.substring(1) != DataPacket.ID_BROADCAST) {
             lifecycleScope.launch {
                 repeatOnLifecycle(Lifecycle.State.STARTED) {
-                    val channelNumber = contactKey[0].digitToInt()
                     model.channels.collect { channels ->
                         val channelName =
                             channels.getChannel(channelNumber)?.name ?: "Unknown Channel"