Merge pull request #48 from rootstrap/enhacement/security

Shared pref security

Author: amaury901130

.idea/misc.xml

@@ -17,7 +17,7 @@ android {
     dataBinding.enabled = true
     defaultConfig {
         applicationId "com.rootstrap.android"
-        minSdkVersion 21
+        minSdkVersion 23
         targetSdkVersion 29
         versionCode 42
         versionName "1.0"
@@ -66,18 +66,24 @@ android {
             applicationIdSuffix ".dev"
             versionNameSuffix "-dev"
             buildConfigField("String", "API_URL", "\"https://rails5-api-base.herokuapp.com/api/v1/\"")
+            buildConfigField("String", "SECURE_KEY_ALIAS", "\"$projectKeyAlias\"")
+            buildConfigField("String", "SECURE_FILE_NAME", "\"appPreferencesDev\"")
         }
 
         staging {
             dimension "server"
             applicationIdSuffix ".staging"
             versionNameSuffix "-staging"
             buildConfigField("String", "API_URL", "\"https://proj-staging.herokuapp.com/api/\"")
+            buildConfigField("String", "SECURE_KEY_ALIAS", "\"$projectKeyAlias\"")
+            buildConfigField("String", "SECURE_FILE_NAME", "\"appPreferencesStaging\"")
         }
 
         prod {
             dimension "server"
             buildConfigField("String", "API_URL", "\"https://proj-production.herokuapp.com/api/\"")
+            buildConfigField("String", "SECURE_KEY_ALIAS", "\"$projectKeyAlias\"")
+            buildConfigField("String", "SECURE_FILE_NAME", "\"appPreferences\"")
         }
     }
 
@@ -188,4 +194,7 @@ dependencies {
     kapt 'androidx.hilt:hilt-compiler:1.0.0-alpha02'
     androidTestImplementation 'com.google.dagger:hilt-android-testing:2.28-alpha'
     kaptAndroidTest 'com.google.dagger:hilt-android-compiler:2.28-alpha'
+
+    //security crypto
+    implementation "androidx.security:security-crypto:1.1.0-alpha03"
 }

.idea/runConfigurations.xml

@@ -0,0 +1,39 @@
+package com.rootstrap.android.tests.utils
+
+import android.content.SharedPreferences
+import androidx.security.crypto.EncryptedSharedPreferences
+import com.rootstrap.android.util.Prefs
+import dagger.hilt.android.testing.HiltAndroidRule
+import dagger.hilt.android.testing.HiltAndroidTest
+import org.junit.Assert
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import java.util.* // ktlint-disable no-wildcard-imports
+import javax.inject.Inject
+
+@HiltAndroidTest
+class PrefTests {
+    @get:Rule
+    var hiltRule = HiltAndroidRule(this)
+
+    @Inject
+    lateinit var prefs: Prefs
+
+    @Inject
+    lateinit var preferences: SharedPreferences
+
+    @Before
+    fun init() {
+        hiltRule.inject()
+    }
+
+    @Test
+    fun savingSecureDataPrefs() {
+        val uid = UUID.randomUUID().toString()
+        prefs.uid = uid
+
+        Assert.assertTrue(preferences is EncryptedSharedPreferences)
+        Assert.assertEquals(prefs.uid, uid)
+    }
+}

app/build.gradle

@@ -2,7 +2,11 @@ package com.rootstrap.android.util
 
 import android.content.Context
 import android.content.SharedPreferences
-import androidx.preference.PreferenceManager
+import android.security.keystore.KeyGenParameterSpec
+import android.security.keystore.KeyProperties
+import androidx.security.crypto.EncryptedSharedPreferences
+import androidx.security.crypto.MasterKey
+import com.rootstrap.android.BuildConfig
 import com.squareup.otto.Bus
 import dagger.Module
 import dagger.Provides
@@ -18,7 +22,27 @@ class UtilModule {
     @Provides
     @Singleton
     fun provideSharedPreferences(@ApplicationContext context: Context): SharedPreferences {
-        return PreferenceManager.getDefaultSharedPreferences(context)
+
+        val spec = KeyGenParameterSpec.Builder(
+            BuildConfig.SECURE_KEY_ALIAS,
+            KeyProperties.PURPOSE_ENCRYPT or KeyProperties.PURPOSE_DECRYPT
+            )
+            .setBlockModes(KeyProperties.BLOCK_MODE_GCM)
+            .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE)
+            .setKeySize(256)
+            .build()
+
+        val masterKey = MasterKey.Builder(context, BuildConfig.SECURE_KEY_ALIAS)
+            .setKeyGenParameterSpec(spec)
+            .build()
+
+        return EncryptedSharedPreferences.create(
+            context,
+            BuildConfig.SECURE_FILE_NAME,
+            masterKey,
+            EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
+            EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM
+        )
     }
 
     @Provides