diff --git a/DataControl-0.1.0.apk b/DataControl-0.1.0.apk
index da44467..d4bcf80 100644
Binary files a/DataControl-0.1.0.apk and b/DataControl-0.1.0.apk differ
diff --git a/app/src/main/java/com/jttools/datacontrol/data/AppSettings.kt b/app/src/main/java/com/jttools/datacontrol/data/AppSettings.kt
index e248913..100d87b 100644
--- a/app/src/main/java/com/jttools/datacontrol/data/AppSettings.kt
+++ b/app/src/main/java/com/jttools/datacontrol/data/AppSettings.kt
@@ -15,10 +15,15 @@ data class AppSettings(
     val cutoffIntervalMinutes: Int = 15,
     val baselineMobileBytesAtReset: Long = 0L,
     val whitelistedPackages: Set<String> = emptySet(),
-    val showSystemApps: Boolean = false
+    val showSystemApps: Boolean = false,
+    val passwordHash: String? = null,
+    val passwordSalt: String? = null
 ) {
     val planStartDate: LocalDate get() = LocalDate.ofEpochDay(planStartDateEpochDay)
 
+    /** Un mot de passe de verrouillage protège la désactivation du contrôle et l'accès aux réglages. */
+    val hasPassword: Boolean get() = !passwordHash.isNullOrEmpty()
+
     /** Prochaine date de réinitialisation automatique (anniversaire mensuel du début de forfait). */
     fun nextAutoResetDate(): LocalDate {
         var next = planStartDate.plusMonths(1)
diff --git a/app/src/main/java/com/jttools/datacontrol/data/PasswordHasher.kt b/app/src/main/java/com/jttools/datacontrol/data/PasswordHasher.kt
new file mode 100644
index 0000000..f9cecfc
--- /dev/null
+++ b/app/src/main/java/com/jttools/datacontrol/data/PasswordHasher.kt
@@ -0,0 +1,23 @@
+package com.jttools.datacontrol.data
+
+import java.security.MessageDigest
+import java.security.SecureRandom
+
+/** Hachage salé (SHA-256) du mot de passe de verrouillage — jamais stocké en clair. */
+object PasswordHasher {
+    private const val SALT_BYTES = 16
+
+    fun newSalt(): String {
+        val bytes = ByteArray(SALT_BYTES)
+        SecureRandom().nextBytes(bytes)
+        return bytes.toHex()
+    }
+
+    fun hash(password: String, saltHex: String): String {
+        val digest = MessageDigest.getInstance("SHA-256")
+        digest.update(saltHex.toByteArray(Charsets.UTF_8))
+        return digest.digest(password.toByteArray(Charsets.UTF_8)).toHex()
+    }
+
+    private fun ByteArray.toHex(): String = joinToString("") { "%02x".format(it) }
+}
diff --git a/app/src/main/java/com/jttools/datacontrol/data/SettingsRepository.kt b/app/src/main/java/com/jttools/datacontrol/data/SettingsRepository.kt
index 00f9276..08d2a2f 100644
--- a/app/src/main/java/com/jttools/datacontrol/data/SettingsRepository.kt
+++ b/app/src/main/java/com/jttools/datacontrol/data/SettingsRepository.kt
@@ -6,10 +6,12 @@ import androidx.datastore.preferences.core.doublePreferencesKey
 import androidx.datastore.preferences.core.edit
 import androidx.datastore.preferences.core.longPreferencesKey
 import androidx.datastore.preferences.core.intPreferencesKey
+import androidx.datastore.preferences.core.stringPreferencesKey
 import androidx.datastore.preferences.core.stringSetPreferencesKey
 import androidx.datastore.preferences.preferencesDataStore
 import dagger.hilt.android.qualifiers.ApplicationContext
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.map
 import java.time.LocalDate
 import javax.inject.Inject
@@ -32,6 +34,8 @@ class SettingsRepository @Inject constructor(
         val BASELINE_MOBILE_BYTES = longPreferencesKey("baseline_mobile_bytes")
         val WHITELISTED_PACKAGES = stringSetPreferencesKey("whitelisted_packages")
         val SHOW_SYSTEM_APPS = booleanPreferencesKey("show_system_apps")
+        val PASSWORD_HASH = stringPreferencesKey("password_hash")
+        val PASSWORD_SALT = stringPreferencesKey("password_salt")
     }
 
     val settingsFlow: Flow<AppSettings> = context.dataStore.data.map { prefs ->
@@ -46,7 +50,9 @@ class SettingsRepository @Inject constructor(
             cutoffIntervalMinutes = prefs[Keys.CUTOFF_INTERVAL_MINUTES] ?: defaults.cutoffIntervalMinutes,
             baselineMobileBytesAtReset = prefs[Keys.BASELINE_MOBILE_BYTES] ?: defaults.baselineMobileBytesAtReset,
             whitelistedPackages = prefs[Keys.WHITELISTED_PACKAGES] ?: defaults.whitelistedPackages,
-            showSystemApps = prefs[Keys.SHOW_SYSTEM_APPS] ?: defaults.showSystemApps
+            showSystemApps = prefs[Keys.SHOW_SYSTEM_APPS] ?: defaults.showSystemApps,
+            passwordHash = prefs[Keys.PASSWORD_HASH],
+            passwordSalt = prefs[Keys.PASSWORD_SALT]
         )
     }
 
@@ -95,4 +101,29 @@ class SettingsRepository @Inject constructor(
     suspend fun rebaseline(currentMobileBytes: Long) {
         context.dataStore.edit { it[Keys.BASELINE_MOBILE_BYTES] = currentMobileBytes }
     }
+
+    /** Définit (ou supprime, si [password] est vide/null) le mot de passe de verrouillage. */
+    suspend fun setPassword(password: String?) {
+        if (password.isNullOrBlank()) {
+            context.dataStore.edit {
+                it.remove(Keys.PASSWORD_HASH)
+                it.remove(Keys.PASSWORD_SALT)
+            }
+        } else {
+            val salt = PasswordHasher.newSalt()
+            val hash = PasswordHasher.hash(password, salt)
+            context.dataStore.edit { prefs ->
+                prefs[Keys.PASSWORD_HASH] = hash
+                prefs[Keys.PASSWORD_SALT] = salt
+            }
+        }
+    }
+
+    /** Vrai si aucun mot de passe n'est défini, ou si [password] correspond au mot de passe stocké. */
+    suspend fun verifyPassword(password: String): Boolean {
+        val prefs = context.dataStore.data.first()
+        val hash = prefs[Keys.PASSWORD_HASH] ?: return true
+        val salt = prefs[Keys.PASSWORD_SALT] ?: return true
+        return PasswordHasher.hash(password, salt) == hash
+    }
 }
diff --git a/app/src/main/java/com/jttools/datacontrol/ui/about/AboutScreen.kt b/app/src/main/java/com/jttools/datacontrol/ui/about/AboutScreen.kt
new file mode 100644
index 0000000..a742f62
--- /dev/null
+++ b/app/src/main/java/com/jttools/datacontrol/ui/about/AboutScreen.kt
@@ -0,0 +1,105 @@
+package com.jttools.datacontrol.ui.about
+
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.Card
+import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import com.jttools.datacontrol.R
+
+@Composable
+fun AboutScreen() {
+    val context = LocalContext.current
+    val versionName = remember {
+        runCatching { context.packageManager.getPackageInfo(context.packageName, 0).versionName }
+            .getOrNull() ?: "?"
+    }
+
+    Column(
+        modifier = Modifier
+            .fillMaxSize()
+            .verticalScroll(rememberScrollState())
+            .padding(20.dp),
+        verticalArrangement = Arrangement.spacedBy(16.dp)
+    ) {
+        Text(stringResource(R.string.about_title), style = MaterialTheme.typography.headlineMedium)
+
+        Card(shape = RoundedCornerShape(20.dp), elevation = CardDefaults.cardElevation(2.dp)) {
+            Column(
+                Modifier
+                    .fillMaxWidth()
+                    .padding(24.dp),
+                horizontalAlignment = Alignment.CenterHorizontally,
+                verticalArrangement = Arrangement.spacedBy(6.dp)
+            ) {
+                Image(
+                    painter = painterResource(R.mipmap.ic_launcher),
+                    contentDescription = null,
+                    modifier = Modifier.size(72.dp)
+                )
+                Text(
+                    stringResource(R.string.app_name),
+                    style = MaterialTheme.typography.titleLarge,
+                    fontWeight = FontWeight.Bold
+                )
+                Text(
+                    stringResource(R.string.about_version, versionName),
+                    style = MaterialTheme.typography.bodyMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant
+                )
+            }
+        }
+
+        Card(shape = RoundedCornerShape(20.dp), elevation = CardDefaults.cardElevation(2.dp)) {
+            Column(Modifier.padding(20.dp), verticalArrangement = Arrangement.spacedBy(10.dp)) {
+                Text(stringResource(R.string.about_section_description), style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold)
+                HorizontalDivider()
+                Text(stringResource(R.string.about_description), style = MaterialTheme.typography.bodyMedium)
+            }
+        }
+
+        Card(shape = RoundedCornerShape(20.dp), elevation = CardDefaults.cardElevation(2.dp)) {
+            Column(Modifier.padding(20.dp), verticalArrangement = Arrangement.spacedBy(10.dp)) {
+                Text(stringResource(R.string.about_section_how), style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold)
+                HorizontalDivider()
+                Text(stringResource(R.string.about_how_it_works), style = MaterialTheme.typography.bodyMedium)
+            }
+        }
+
+        Card(shape = RoundedCornerShape(20.dp), elevation = CardDefaults.cardElevation(2.dp)) {
+            Row(
+                Modifier
+                    .fillMaxWidth()
+                    .padding(20.dp),
+                horizontalArrangement = Arrangement.SpaceBetween
+            ) {
+                Text(stringResource(R.string.about_author), style = MaterialTheme.typography.bodyMedium)
+                Text(
+                    stringResource(R.string.about_author_value),
+                    style = MaterialTheme.typography.bodyMedium,
+                    fontWeight = FontWeight.SemiBold
+                )
+            }
+        }
+    }
+}
diff --git a/app/src/main/java/com/jttools/datacontrol/ui/components/PasswordComponents.kt b/app/src/main/java/com/jttools/datacontrol/ui/components/PasswordComponents.kt
new file mode 100644
index 0000000..d3d75d7
--- /dev/null
+++ b/app/src/main/java/com/jttools/datacontrol/ui/components/PasswordComponents.kt
@@ -0,0 +1,141 @@
+package com.jttools.datacontrol.ui.components
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Lock
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Button
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.text.input.PasswordVisualTransformation
+import androidx.compose.ui.unit.dp
+import com.jttools.datacontrol.R
+import kotlinx.coroutines.launch
+
+/**
+ * Verrouille [content] derrière une saisie de mot de passe tant que [passwordSet] est vrai.
+ * Le déverrouillage n'est valable que pour la composition courante (redemandé à chaque visite de l'écran).
+ */
+@Composable
+fun PasswordGate(
+    passwordSet: Boolean,
+    verify: suspend (String) -> Boolean,
+    content: @Composable () -> Unit
+) {
+    var unlocked by remember(passwordSet) { mutableStateOf(!passwordSet) }
+    if (unlocked) {
+        content()
+        return
+    }
+
+    var password by remember { mutableStateOf("") }
+    var error by remember { mutableStateOf(false) }
+    val scope = rememberCoroutineScope()
+
+    Column(
+        modifier = Modifier.fillMaxSize().padding(32.dp),
+        horizontalAlignment = Alignment.CenterHorizontally,
+        verticalArrangement = Arrangement.Center
+    ) {
+        Icon(Icons.Filled.Lock, contentDescription = null, modifier = Modifier.size(48.dp))
+        Spacer(Modifier.height(16.dp))
+        Text(stringResource(R.string.password_gate_title), style = MaterialTheme.typography.titleMedium)
+        Spacer(Modifier.height(16.dp))
+        OutlinedTextField(
+            value = password,
+            onValueChange = { password = it; error = false },
+            label = { Text(stringResource(R.string.password_field_label)) },
+            visualTransformation = PasswordVisualTransformation(),
+            keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Password),
+            isError = error,
+            singleLine = true,
+            modifier = Modifier.fillMaxWidth()
+        )
+        if (error) {
+            Spacer(Modifier.height(4.dp))
+            Text(
+                stringResource(R.string.password_incorrect),
+                color = MaterialTheme.colorScheme.error,
+                style = MaterialTheme.typography.bodySmall
+            )
+        }
+        Spacer(Modifier.height(16.dp))
+        Button(
+            onClick = {
+                scope.launch {
+                    if (verify(password)) {
+                        unlocked = true
+                    } else {
+                        error = true
+                    }
+                }
+            },
+            modifier = Modifier.fillMaxWidth()
+        ) { Text(stringResource(R.string.password_unlock)) }
+    }
+}
+
+/** Boîte de dialogue de saisie de mot de passe pour confirmer une action ponctuelle (ex : désactivation). */
+@Composable
+fun PasswordPromptDialog(
+    title: String,
+    error: Boolean,
+    onDismiss: () -> Unit,
+    onConfirm: (String) -> Unit
+) {
+    var password by remember { mutableStateOf("") }
+
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text(title) },
+        text = {
+            Column {
+                OutlinedTextField(
+                    value = password,
+                    onValueChange = { password = it },
+                    label = { Text(stringResource(R.string.password_field_label)) },
+                    visualTransformation = PasswordVisualTransformation(),
+                    keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Password),
+                    isError = error,
+                    singleLine = true,
+                    modifier = Modifier.fillMaxWidth()
+                )
+                if (error) {
+                    Spacer(Modifier.height(4.dp))
+                    Text(
+                        stringResource(R.string.password_incorrect),
+                        color = MaterialTheme.colorScheme.error,
+                        style = MaterialTheme.typography.bodySmall
+                    )
+                }
+            }
+        },
+        confirmButton = {
+            Button(onClick = { onConfirm(password) }) { Text(stringResource(R.string.common_confirm)) }
+        },
+        dismissButton = {
+            OutlinedButton(onClick = onDismiss) { Text(stringResource(R.string.common_cancel)) }
+        }
+    )
+}
diff --git a/app/src/main/java/com/jttools/datacontrol/ui/dashboard/DashboardScreen.kt b/app/src/main/java/com/jttools/datacontrol/ui/dashboard/DashboardScreen.kt
index b3b8cc0..9ca5f2f 100644
--- a/app/src/main/java/com/jttools/datacontrol/ui/dashboard/DashboardScreen.kt
+++ b/app/src/main/java/com/jttools/datacontrol/ui/dashboard/DashboardScreen.kt
@@ -27,6 +27,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
@@ -40,12 +41,14 @@ import com.jttools.datacontrol.R
 import com.jttools.datacontrol.data.DataState
 import com.jttools.datacontrol.service.DataMonitorService
 import com.jttools.datacontrol.ui.SystemActions
+import com.jttools.datacontrol.ui.components.PasswordPromptDialog
 import com.jttools.datacontrol.ui.theme.StateCut
 import com.jttools.datacontrol.ui.theme.StateOk
 import com.jttools.datacontrol.ui.theme.StateWarning
 import com.jttools.datacontrol.ui.theme.StateWifi
 import java.time.format.DateTimeFormatter
 import java.util.Locale
+import kotlinx.coroutines.launch
 
 @Composable
 fun DashboardScreen(systemActions: SystemActions) {
@@ -54,6 +57,9 @@ fun DashboardScreen(systemActions: SystemActions) {
     val settings by viewModel.settings.collectAsStateWithLifecycle()
     val snapshot by viewModel.snapshot.collectAsStateWithLifecycle()
     var showResetDialog by remember { mutableStateOf(false) }
+    var showDisablePasswordDialog by remember { mutableStateOf(false) }
+    var disablePasswordError by remember { mutableStateOf(false) }
+    val scope = rememberCoroutineScope()
 
     val stateColor = when {
         !snapshot.serviceRunning -> Color.Gray
@@ -165,7 +171,12 @@ fun DashboardScreen(systemActions: SystemActions) {
                                     }
                                 }
                             } else {
-                                viewModel.setControlEnabled(false)
+                                if (settings.hasPassword) {
+                                    disablePasswordError = false
+                                    showDisablePasswordDialog = true
+                                } else {
+                                    viewModel.setControlEnabled(false)
+                                }
                             }
                         }
                     )
@@ -205,6 +216,24 @@ fun DashboardScreen(systemActions: SystemActions) {
             }
         )
     }
+
+    if (showDisablePasswordDialog) {
+        PasswordPromptDialog(
+            title = stringResource(R.string.password_gate_title),
+            error = disablePasswordError,
+            onDismiss = { showDisablePasswordDialog = false },
+            onConfirm = { password ->
+                scope.launch {
+                    if (viewModel.verifyPassword(password)) {
+                        viewModel.setControlEnabled(false)
+                        showDisablePasswordDialog = false
+                    } else {
+                        disablePasswordError = true
+                    }
+                }
+            }
+        )
+    }
 }
 
 @Composable
diff --git a/app/src/main/java/com/jttools/datacontrol/ui/dashboard/DashboardViewModel.kt b/app/src/main/java/com/jttools/datacontrol/ui/dashboard/DashboardViewModel.kt
index ecd9ab5..77c9a7d 100644
--- a/app/src/main/java/com/jttools/datacontrol/ui/dashboard/DashboardViewModel.kt
+++ b/app/src/main/java/com/jttools/datacontrol/ui/dashboard/DashboardViewModel.kt
@@ -32,4 +32,6 @@ class DashboardViewModel @Inject constructor(
     fun resetPlanNow() {
         viewModelScope.launch { settingsRepository.resetPlan(usageRepository.totalMobileBytes()) }
     }
+
+    suspend fun verifyPassword(password: String): Boolean = settingsRepository.verifyPassword(password)
 }
diff --git a/app/src/main/java/com/jttools/datacontrol/ui/navigation/DataControlNavHost.kt b/app/src/main/java/com/jttools/datacontrol/ui/navigation/DataControlNavHost.kt
index 5506f5b..5911a60 100644
--- a/app/src/main/java/com/jttools/datacontrol/ui/navigation/DataControlNavHost.kt
+++ b/app/src/main/java/com/jttools/datacontrol/ui/navigation/DataControlNavHost.kt
@@ -3,6 +3,7 @@ package com.jttools.datacontrol.ui.navigation
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.List
 import androidx.compose.material.icons.filled.Dashboard
+import androidx.compose.material.icons.filled.Info
 import androidx.compose.material.icons.filled.Settings
 import androidx.compose.material3.Icon
 import androidx.compose.material3.NavigationBar
@@ -22,6 +23,7 @@ import androidx.navigation.compose.rememberNavController
 import androidx.compose.ui.res.stringResource
 import com.jttools.datacontrol.R
 import com.jttools.datacontrol.ui.SystemActions
+import com.jttools.datacontrol.ui.about.AboutScreen
 import com.jttools.datacontrol.ui.dashboard.DashboardScreen
 import com.jttools.datacontrol.ui.settings.SettingsScreen
 import com.jttools.datacontrol.ui.whitelist.WhitelistScreen
@@ -30,9 +32,10 @@ private sealed class Destination(val route: String, val labelRes: Int, val icon:
     data object Dashboard : Destination("dashboard", R.string.nav_dashboard, Icons.Filled.Dashboard)
     data object Settings : Destination("settings", R.string.nav_settings, Icons.Filled.Settings)
     data object Whitelist : Destination("whitelist", R.string.nav_whitelist, Icons.AutoMirrored.Filled.List)
+    data object About : Destination("about", R.string.nav_about, Icons.Filled.Info)
 }
 
-private val destinations = listOf(Destination.Dashboard, Destination.Settings, Destination.Whitelist)
+private val destinations = listOf(Destination.Dashboard, Destination.Settings, Destination.Whitelist, Destination.About)
 
 @Composable
 fun DataControlNavHost(systemActions: SystemActions) {
@@ -69,6 +72,7 @@ fun DataControlNavHost(systemActions: SystemActions) {
             composable(Destination.Dashboard.route) { DashboardScreen(systemActions) }
             composable(Destination.Settings.route) { SettingsScreen(systemActions) }
             composable(Destination.Whitelist.route) { WhitelistScreen() }
+            composable(Destination.About.route) { AboutScreen() }
         }
     }
 }
diff --git a/app/src/main/java/com/jttools/datacontrol/ui/settings/SettingsScreen.kt b/app/src/main/java/com/jttools/datacontrol/ui/settings/SettingsScreen.kt
index 4d31f56..956d527 100644
--- a/app/src/main/java/com/jttools/datacontrol/ui/settings/SettingsScreen.kt
+++ b/app/src/main/java/com/jttools/datacontrol/ui/settings/SettingsScreen.kt
@@ -33,11 +33,14 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.text.input.PasswordVisualTransformation
 import androidx.compose.ui.unit.dp
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.jttools.datacontrol.R
 import com.jttools.datacontrol.ui.SystemActions
+import com.jttools.datacontrol.ui.components.PasswordGate
+import com.jttools.datacontrol.ui.theme.StateOk
 import java.time.Instant
 import java.time.LocalDate
 import java.time.ZoneOffset
@@ -50,6 +53,18 @@ fun SettingsScreen(systemActions: SystemActions) {
     val viewModel: SettingsViewModel = hiltViewModel()
     val settings by viewModel.settings.collectAsStateWithLifecycle()
 
+    PasswordGate(passwordSet = settings.hasPassword, verify = { viewModel.verifyPassword(it) }) {
+        SettingsContent(systemActions, viewModel, settings)
+    }
+}
+
+@OptIn(androidx.compose.material3.ExperimentalMaterial3Api::class)
+@Composable
+private fun SettingsContent(
+    systemActions: SystemActions,
+    viewModel: SettingsViewModel,
+    settings: com.jttools.datacontrol.data.AppSettings
+) {
     var planLimitText by remember(settings.planLimitMo) { mutableStateOf(settings.planLimitMo.toString()) }
     var planPriceText by remember(settings.planPriceEuro) { mutableStateOf(settings.planPriceEuro.toString()) }
     var overagePriceText by remember(settings.overagePricePerMoEuro) { mutableStateOf(settings.overagePricePerMoEuro.toString()) }
@@ -61,6 +76,15 @@ fun SettingsScreen(systemActions: SystemActions) {
     var notifGranted by remember { mutableStateOf(systemActions.hasNotificationPermission()) }
     var batteryIgnored by remember { mutableStateOf(systemActions.isIgnoringBatteryOptimizations()) }
 
+    var newPassword by remember { mutableStateOf("") }
+    var confirmPassword by remember { mutableStateOf("") }
+    var passwordError by remember { mutableStateOf<String?>(null) }
+    var passwordMessage by remember { mutableStateOf<String?>(null) }
+    val passwordTooShort = stringResource(R.string.settings_password_too_short)
+    val passwordMismatch = stringResource(R.string.settings_password_mismatch)
+    val passwordSetMessage = stringResource(R.string.settings_password_set_confirmation)
+    val passwordRemovedMessage = stringResource(R.string.settings_password_removed_confirmation)
+
     LaunchedEffect(Unit) {
         vpnGranted = systemActions.isVpnPrepared()
         notifGranted = systemActions.hasNotificationPermission()
@@ -174,6 +198,68 @@ fun SettingsScreen(systemActions: SystemActions) {
             }
         }
 
+        Card(shape = RoundedCornerShape(20.dp), elevation = CardDefaults.cardElevation(2.dp)) {
+            Column(Modifier.padding(20.dp), verticalArrangement = Arrangement.spacedBy(10.dp)) {
+                Text(stringResource(R.string.settings_section_security), style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold)
+                HorizontalDivider()
+                Text(
+                    if (settings.hasPassword) stringResource(R.string.settings_password_active)
+                    else stringResource(R.string.settings_password_inactive),
+                    style = MaterialTheme.typography.bodyMedium,
+                    color = if (settings.hasPassword) StateOk else MaterialTheme.colorScheme.onSurfaceVariant
+                )
+                OutlinedTextField(
+                    value = newPassword,
+                    onValueChange = { newPassword = it; passwordError = null; passwordMessage = null },
+                    label = { Text(stringResource(R.string.settings_password_new)) },
+                    visualTransformation = PasswordVisualTransformation(),
+                    keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Password),
+                    singleLine = true,
+                    modifier = Modifier.fillMaxWidth()
+                )
+                OutlinedTextField(
+                    value = confirmPassword,
+                    onValueChange = { confirmPassword = it; passwordError = null; passwordMessage = null },
+                    label = { Text(stringResource(R.string.settings_password_confirm)) },
+                    visualTransformation = PasswordVisualTransformation(),
+                    keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Password),
+                    singleLine = true,
+                    modifier = Modifier.fillMaxWidth()
+                )
+                passwordError?.let {
+                    Text(it, color = MaterialTheme.colorScheme.error, style = MaterialTheme.typography.bodySmall)
+                }
+                passwordMessage?.let {
+                    Text(it, color = StateOk, style = MaterialTheme.typography.bodySmall)
+                }
+                Row(horizontalArrangement = Arrangement.spacedBy(10.dp)) {
+                    Button(onClick = {
+                        when {
+                            newPassword.length < 4 -> passwordError = passwordTooShort
+                            newPassword != confirmPassword -> passwordError = passwordMismatch
+                            else -> {
+                                viewModel.setPassword(newPassword)
+                                newPassword = ""
+                                confirmPassword = ""
+                                passwordError = null
+                                passwordMessage = passwordSetMessage
+                            }
+                        }
+                    }) { Text(stringResource(R.string.settings_password_set)) }
+
+                    if (settings.hasPassword) {
+                        OutlinedButton(onClick = {
+                            viewModel.setPassword(null)
+                            newPassword = ""
+                            confirmPassword = ""
+                            passwordError = null
+                            passwordMessage = passwordRemovedMessage
+                        }) { Text(stringResource(R.string.settings_password_remove)) }
+                    }
+                }
+            }
+        }
+
         Button(
             onClick = {
                 viewModel.updatePlan(
diff --git a/app/src/main/java/com/jttools/datacontrol/ui/settings/SettingsViewModel.kt b/app/src/main/java/com/jttools/datacontrol/ui/settings/SettingsViewModel.kt
index 3914f00..fd2526c 100644
--- a/app/src/main/java/com/jttools/datacontrol/ui/settings/SettingsViewModel.kt
+++ b/app/src/main/java/com/jttools/datacontrol/ui/settings/SettingsViewModel.kt
@@ -37,4 +37,10 @@ class SettingsViewModel @Inject constructor(
     fun setStartDate(date: LocalDate) {
         viewModelScope.launch { settingsRepository.setStartDate(date) }
     }
+
+    fun setPassword(password: String?) {
+        viewModelScope.launch { settingsRepository.setPassword(password) }
+    }
+
+    suspend fun verifyPassword(password: String): Boolean = settingsRepository.verifyPassword(password)
 }
diff --git a/app/src/main/java/com/jttools/datacontrol/ui/whitelist/WhitelistScreen.kt b/app/src/main/java/com/jttools/datacontrol/ui/whitelist/WhitelistScreen.kt
index 449d806..3314b18 100644
--- a/app/src/main/java/com/jttools/datacontrol/ui/whitelist/WhitelistScreen.kt
+++ b/app/src/main/java/com/jttools/datacontrol/ui/whitelist/WhitelistScreen.kt
@@ -39,11 +39,20 @@ import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.jttools.datacontrol.R
 import com.jttools.datacontrol.data.AppInfo
+import com.jttools.datacontrol.ui.components.PasswordGate
 
 @Composable
 fun WhitelistScreen() {
     val viewModel: WhitelistViewModel = hiltViewModel()
     val settings by viewModel.settings.collectAsStateWithLifecycle()
+
+    PasswordGate(passwordSet = settings.hasPassword, verify = { viewModel.verifyPassword(it) }) {
+        WhitelistContent(viewModel, settings)
+    }
+}
+
+@Composable
+private fun WhitelistContent(viewModel: WhitelistViewModel, settings: com.jttools.datacontrol.data.AppSettings) {
     val apps by viewModel.apps.collectAsStateWithLifecycle()
     val loading by viewModel.loading.collectAsStateWithLifecycle()
     var query by remember { mutableStateOf("") }
diff --git a/app/src/main/java/com/jttools/datacontrol/ui/whitelist/WhitelistViewModel.kt b/app/src/main/java/com/jttools/datacontrol/ui/whitelist/WhitelistViewModel.kt
index fbd97a6..a35376a 100644
--- a/app/src/main/java/com/jttools/datacontrol/ui/whitelist/WhitelistViewModel.kt
+++ b/app/src/main/java/com/jttools/datacontrol/ui/whitelist/WhitelistViewModel.kt
@@ -48,4 +48,6 @@ class WhitelistViewModel @Inject constructor(
     fun setShowSystemApps(show: Boolean) {
         viewModelScope.launch { settingsRepository.setShowSystemApps(show) }
     }
+
+    suspend fun verifyPassword(password: String): Boolean = settingsRepository.verifyPassword(password)
 }
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index e259bbf..c55b251 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -6,6 +6,7 @@
     <string name="nav_dashboard">Tableau de bord</string>
     <string name="nav_settings">Réglages</string>
     <string name="nav_whitelist">Liste blanche</string>
+    <string name="nav_about">À propos</string>
 
     <!-- Dashboard -->
     <string name="dashboard_title">Tableau de bord</string>
@@ -57,6 +58,33 @@
     <string name="settings_save">Enregistrer</string>
     <string name="settings_edit_date">Modifier</string>
     <string name="settings_saved">Réglages enregistrés</string>
+    <string name="settings_section_security">Sécurité</string>
+    <string name="settings_password_active">Mot de passe actif — protège la désactivation et les réglages</string>
+    <string name="settings_password_inactive">Aucun mot de passe défini</string>
+    <string name="settings_password_new">Nouveau mot de passe</string>
+    <string name="settings_password_confirm">Confirmer le mot de passe</string>
+    <string name="settings_password_set">Définir</string>
+    <string name="settings_password_remove">Supprimer</string>
+    <string name="settings_password_too_short">Le mot de passe doit contenir au moins 4 caractères</string>
+    <string name="settings_password_mismatch">Les mots de passe ne correspondent pas</string>
+    <string name="settings_password_set_confirmation">Mot de passe enregistré</string>
+    <string name="settings_password_removed_confirmation">Mot de passe supprimé</string>
+
+    <!-- Verrouillage par mot de passe -->
+    <string name="password_gate_title">Zone protégée</string>
+    <string name="password_field_label">Mot de passe</string>
+    <string name="password_incorrect">Mot de passe incorrect</string>
+    <string name="password_unlock">Déverrouiller</string>
+
+    <!-- About -->
+    <string name="about_title">À propos</string>
+    <string name="about_version">Version %1$s</string>
+    <string name="about_section_description">Description</string>
+    <string name="about_description">DataControl surveille en arrière-plan la consommation de données mobiles et coupe automatiquement l\'accès à Internet en cas de dépassement du forfait, sans jamais toucher au Wi-Fi.</string>
+    <string name="about_section_how">Fonctionnement</string>
+    <string name="about_how_it_works">Le filtrage repose sur un pare-feu local basé sur VpnService (sans root) : le trafic des applications non autorisées est capturé dans un tunnel VPN local puis silencieusement ignoré, tandis que les applications de la liste blanche continuent de communiquer normalement.</string>
+    <string name="about_author">Auteur</string>
+    <string name="about_author_value">JT-Tools — Johnny</string>
 
     <!-- Whitelist -->
     <string name="whitelist_title">Liste blanche</string>