diff --git a/app/src/main/assets/config.static b/app/src/main/assets/config.static
index 476d4e8a..0fec9245 100644
--- a/app/src/main/assets/config.static
+++ b/app/src/main/assets/config.static
@@ -21,7 +21,6 @@ audio_jitter_buffer_size 50
 rtp_stats yes
 rtp_timeout 60
 rtp_rxmode thread
-sip_cuser_random yes
 module aaudio.so
 module stun.so
 module turn.so
diff --git a/app/src/main/kotlin/com/tutpro/baresip/Config.kt b/app/src/main/kotlin/com/tutpro/baresip/Config.kt
index fe0b07ed..f1f20994 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/Config.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/Config.kt
@@ -115,6 +115,12 @@ object Config {
         if (userAgent != "")
             config = "${config}user_agent $userAgent\n"
 
+        val sipCuserRandom = previousVariable("sip_cuser_random")
+        config = if (sipCuserRandom != "")
+            "${config}sip_cuser_random $sipCuserRandom\n"
+        else
+            "${config}sip_cuser_random yes\n"
+
         val darkTheme = previousVariable("dark_theme")
         Preferences(ctx).displayTheme = if (darkTheme == "yes") {
             config = "${config}dark_theme yes\n"
diff --git a/app/src/main/kotlin/com/tutpro/baresip/SettingsScreen.kt b/app/src/main/kotlin/com/tutpro/baresip/SettingsScreen.kt
index c93eef4f..181fdef0 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/SettingsScreen.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/SettingsScreen.kt
@@ -762,6 +762,35 @@ private fun SettingsContent(
         }
     }
 
+    @Composable
+    fun UniqueContactUri() {
+        val uniqueContactUriTitle = stringResource(R.string.unique_contact_uri)
+        val uniqueContactUriHelp = stringResource(R.string.unique_contact_uri_help)
+        Row(
+            Modifier
+                .fillMaxWidth()
+                .padding(end = 10.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.Start
+        ) {
+            Text(text = uniqueContactUriTitle,
+                modifier = Modifier
+                    .weight(1f)
+                    .clickable {
+                        alertTitle.value = uniqueContactUriTitle
+                        alertMessage.value = uniqueContactUriHelp
+                        showAlert.value = true
+                    },
+                fontSize = 18.sp
+            )
+            val uniqueContactUri by viewModel.uniqueContactUri.collectAsState()
+            Switch(
+                checked = uniqueContactUri,
+                onCheckedChange = { viewModel.uniqueContactUri.value = it }
+            )
+        }
+    }
+
     @Composable
     fun AudioSettings(navController: NavController) {
         Row(
@@ -1318,6 +1347,7 @@ private fun SettingsContent(
         VerifyServer()
         CaFile(activity)
         UserAgent()
+        UniqueContactUri()
         AudioSettings(navController)
         Contacts(activity)
         Ringtone()
@@ -1435,6 +1465,13 @@ private fun checkOnClick(ctx: Context, viewModel: SettingsViewModel): Boolean {
         restart = true
     }
 
+    if ((Config.variable("sip_cuser_random") == "yes") != viewModel.uniqueContactUri.value) {
+        Config.replaceVariable("sip_cuser_random",
+            if (viewModel.uniqueContactUri.value) "yes" else "no")
+        save = true
+        restart = true
+    }
+
     val ringtoneUri = viewModel.ringtoneUri.value
     Preferences(ctx).ringtoneUri = ringtoneUri
     BaresipService.rt = RingtoneManager.getRingtone(ctx, ringtoneUri.toUri())
diff --git a/app/src/main/kotlin/com/tutpro/baresip/SettingsViewModel.kt b/app/src/main/kotlin/com/tutpro/baresip/SettingsViewModel.kt
index 2f31d436..a3aaa600 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/SettingsViewModel.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/SettingsViewModel.kt
@@ -24,6 +24,7 @@ class SettingsViewModel: ViewModel() {
     val verifyServer = MutableStateFlow(false)
     val caFile = MutableStateFlow(false)
     val userAgent = MutableStateFlow("")
+    val uniqueContactUri =  MutableStateFlow(true)
     val contactsMode = MutableStateFlow("")
     val ringtoneUri = MutableStateFlow("")
     val batteryOptimizations = MutableStateFlow(false)
@@ -62,6 +63,8 @@ class SettingsViewModel: ViewModel() {
 
         userAgent.value = Config.variable("user_agent")
 
+        uniqueContactUri.value =  Config.variable("sip_cuser_random") == "yes"
+
         contactsMode.value = Config.variable("contacts_mode").lowercase()
 
         ringtoneUri.value = if (Preferences(ctx).ringtoneUri == "")
diff --git a/app/src/main/res/values-fi/strings.xml b/app/src/main/res/values-fi/strings.xml
index c0e21ecf..c719cf37 100644
--- a/app/src/main/res/values-fi/strings.xml
+++ b/app/src/main/res/values-fi/strings.xml
@@ -382,6 +382,11 @@
         nimeltään \'ca_certs.crt\' ladataan Download-kansiosta.
     </string>
     <string name="no_read_permission">Ei ulkoisen muistin lukuoikeutta</string>
+    <string name="unique_contact_uri">Uniikki Contact URI</string>
+    <string name="unique_contact_uri_help">Jos merkitty, Contact URI:n taataan olevan uniikki.
+        Merkittävä, jos on useammalla tilillä on same SIP URI:n käyttäjäosa, mutta myös
+        suojaa tilejä hyökkäyksiltä.
+    </string>
     <string name="audio_settings">Audio-asetukset</string>
     <string name="speaker_phone">Kaiutin</string>
     <string name="speaker_phone_help">Jos merkitty, kaiutin kytketään sutomaattisesti päälle
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 9cabcbef..04b2758e 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -364,6 +364,10 @@
         TLS certificates of such Certificate Authorities that are not included in Android OS.
         In Android version 9, a file called \'ca_certs.crt\' is loaded from Download folder.</string>
     <string name="no_read_permission">No External Storage read permission</string>
+    <string name="unique_contact_uri">Unique Contact URI</string>
+    <string name="unique_contact_uri_help">If checked, Contact URI is guaranteed to be unique.
+        Needs to be checked if there is more than one account with the same SIP URI userpart,
+        but also improves protection of the accounts from attacks.</string>
     <string name="audio_settings">Audio Settings</string>
     <string name="speaker_phone">Speaker Phone</string>
     <string name="speaker_phone_help">If checked, speaker phone is turned automatically on