15 files changed, 221 insertions(+), 62 deletions(-)

M app/build.gradle.kts
M app/src/main/java/com/github/nacabaro/vbhelper/di/AppContainer.kt
M app/src/main/java/com/github/nacabaro/vbhelper/di/DefaultAppContainer.kt
M app/src/main/java/com/github/nacabaro/vbhelper/source/ApkSecretsImporter.kt
A app/src/main/java/com/github/nacabaro/vbhelper/source/DataStoreSecretsRepository.kt
M app/src/main/java/com/github/nacabaro/vbhelper/source/DexFileSecretsImporter.kt
D app/src/main/java/com/github/nacabaro/vbhelper/source/Secrets.kt
M app/src/main/java/com/github/nacabaro/vbhelper/source/SecretsImporter.kt
A app/src/main/java/com/github/nacabaro/vbhelper/source/SecretsRepository.kt
A app/src/main/java/com/github/nacabaro/vbhelper/source/SecretsSerializer.kt
A app/src/main/proto/com/github/nacabaro/vbhelper/source/Secrets.proto
M app/src/test/java/com/github/nacabaro/vbhelper/source/ApkSecretsImporterTest.kt
M app/src/test/java/com/github/nacabaro/vbhelper/source/DexFileSecretsImporterTest.kt
M build.gradle.kts
M gradle/libs.versions.toml

@@ 3,6 3,7 @@ plugins {
     alias(libs.plugins.kotlin.android)
     alias(libs.plugins.kotlin.compose)
     id("com.google.devtools.ksp") version "2.0.21-1.0.27"
+    id("com.google.protobuf")
 }
 
 android {


@@ 38,6 39,29 @@ android {
     buildFeatures {
         compose = true
     }
+
+    lint {
+        baseline = file("lint-baseline.xml")
+    }
+}
+
+protobuf {
+    protoc {
+        artifact = "com.google.protobuf:protoc:4.27.0"
+    }
+
+    // Generates the java Protobuf-lite code for the Protobufs in this project. See
+    // https://github.com/google/protobuf-gradle-plugin#customizing-protobuf-compilation
+    // for more information.
+    generateProtoTasks {
+        all().forEach  { task ->
+            task.builtins {
+                create("java") {
+                    option("lite")
+                }
+            }
+        }
+    }
 }
 
 dependencies {


@@ 51,6 75,7 @@ dependencies {
     implementation(libs.androidx.lifecycle.runtime.ktx)
     implementation(libs.androidx.activity.compose)
     implementation(platform(libs.androidx.compose.bom))
+    implementation(libs.androidx.datastore)
     implementation(libs.androidx.ui)
     implementation(libs.androidx.ui.graphics)
     implementation(libs.androidx.ui.tooling.preview)


@@ 64,5 89,6 @@ dependencies {
     debugImplementation(libs.androidx.ui.test.manifest)
     implementation("androidx.navigation:navigation-compose:2.7.0")
     implementation("com.google.android.material:material:1.2.0")
+    implementation(libs.protobuf.javalite)
     implementation("androidx.compose.material:material")
 }=
\ No newline at end of file

@@ 1,7 1,9 @@
 package com.github.nacabaro.vbhelper.di
 
 import com.github.nacabaro.vbhelper.database.AppDatabase
+import com.github.nacabaro.vbhelper.source.DataStoreSecretsRepository
 
 interface AppContainer {
     val db: AppDatabase
+    val dataStoreSecretsRepository: DataStoreSecretsRepository
 }=
\ No newline at end of file

@@ 1,9 1,22 @@
 import android.content.Context
+import androidx.datastore.core.DataStore
+import androidx.datastore.dataStore
 import androidx.room.Room
 import com.github.nacabaro.vbhelper.database.AppDatabase
 import com.github.nacabaro.vbhelper.di.AppContainer
+import com.github.nacabaro.vbhelper.source.DataStoreSecretsRepository
+import com.github.nacabaro.vbhelper.source.SecretsSerializer
+import com.github.nacabaro.vbhelper.source.proto.Secrets
+
+private const val SECRETS_DATA_STORE_NAME = "secrets.pb"
+
+val Context.secretsStore: DataStore<Secrets> by dataStore(
+    fileName = SECRETS_DATA_STORE_NAME,
+    serializer = SecretsSerializer
+)
 
 class DefaultAppContainer(private val context: Context) : AppContainer {
+
     override val db: AppDatabase by lazy {
         Room.databaseBuilder(
             context = context,


@@ 11,4 24,8 @@ class DefaultAppContainer(private val context: Context) : AppContainer {
             "internalDb"
         ).build()
     }
-}>
\ No newline at end of file
+
+    override val dataStoreSecretsRepository = DataStoreSecretsRepository(context.secretsStore)
+
+}
+

@@ 1,5 1,6 @@
 package com.github.nacabaro.vbhelper.source
 
+import com.github.nacabaro.vbhelper.source.proto.Secrets
 import java.io.InputStream
 import java.util.zip.ZipInputStream
 


@@ 10,7 11,7 @@ class ApkSecretsImporter(private val dexFileSecretsImporter: SecretsImporter = D
     }
 
     // importSecrets imports the secrets from the apk input stream, and validates them.
-    override fun importSecrets(inputStream: InputStream): Map<UShort, Secrets> {
+    override fun importSecrets(inputStream: InputStream): Secrets {
         ZipInputStream(inputStream).use { zip ->
             var zipEntry = zip.nextEntry
             while(zipEntry != null) {

@@ 0,0 1,46 @@
+package com.github.nacabaro.vbhelper.source
+
+import androidx.datastore.core.DataStore
+import com.github.cfogrady.vbnfc.CryptographicTransformer
+import com.github.cfogrady.vbnfc.data.DeviceType
+import com.github.nacabaro.vbhelper.source.proto.Secrets
+import com.github.nacabaro.vbhelper.source.proto.Secrets.HmacKeys
+import kotlinx.coroutines.flow.single
+
+class DataStoreSecretsRepository(
+    private val secretsDataStore: DataStore<Secrets>,
+): SecretsRepository {
+    override val secretsFlow = secretsDataStore.data
+
+    override suspend fun updateSecrets(secrets: Secrets) {
+        secretsDataStore.updateData {
+            secrets
+        }
+    }
+
+    override suspend fun getSecrets(): Secrets {
+        return secretsFlow.single()
+    }
+}
+
+private fun Secrets.getHmacKeys(deviceTypeId: UShort): HmacKeys {
+    return when(deviceTypeId) {
+        DeviceType.VitalBraceletBEDeviceType -> this.beHmacKeys
+        DeviceType.VitalCharactersDeviceType -> this.vbcHmacKeys
+        DeviceType.VitalSeriesDeviceType -> this.vbdmHmacKeys
+        else -> throw IllegalArgumentException("Unknown DeviceTypeId")
+    }
+}
+
+fun Secrets.getCryptographicTransformerMap(): Map<UShort, CryptographicTransformer> {
+    val cipher = this.vbCipherList.toIntArray()
+    val beCipher = this.beCipherList.toIntArray()
+    val vbdmHmacKeys = this.getHmacKeys(DeviceType.VitalSeriesDeviceType)
+    val vbcHmacKeys = this.getHmacKeys(DeviceType.VitalCharactersDeviceType)
+    val beHmacKeys = this.getHmacKeys(DeviceType.VitalBraceletBEDeviceType)
+    return mapOf(
+        Pair(DeviceType.VitalSeriesDeviceType, CryptographicTransformer(vbdmHmacKeys.hmacKey1, vbdmHmacKeys.hmacKey2, this.aesKey, cipher)),
+        Pair(DeviceType.VitalCharactersDeviceType, CryptographicTransformer(vbcHmacKeys.hmacKey1, vbcHmacKeys.hmacKey2, this.aesKey, cipher)),
+        Pair(DeviceType.VitalBraceletBEDeviceType, CryptographicTransformer(beHmacKeys.hmacKey1, beHmacKeys.hmacKey2, this.aesKey, beCipher)),
+    )
+}<
\ No newline at end of file

@@ 1,6 1,9 @@
 package com.github.nacabaro.vbhelper.source
 
+import com.github.cfogrady.vbnfc.CryptographicTransformer
 import com.github.cfogrady.vbnfc.data.DeviceType
+import com.github.nacabaro.vbhelper.source.proto.Secrets
+import com.github.nacabaro.vbhelper.source.proto.Secrets.HmacKeys
 import java.io.InputStream
 import java.nio.ByteBuffer
 import java.nio.ByteOrder


@@ 28,63 31,58 @@ class DexFileSecretsImporter: SecretsImporter {
         const val VBC_TEST_TAG_PASSWORD = "a71dfb22"
     }
 
-    override fun importSecrets(inputStream: InputStream): Map<UShort, Secrets> {
+    override fun importSecrets(inputStream: InputStream): Secrets {
         val deviceToSecrets = readSecrets(inputStream)
         verifySecretCorrectness(deviceToSecrets)
         return deviceToSecrets
     }
 
-    private fun readSecrets(inputStream: InputStream): Map<UShort, Secrets> {
+    private fun readSecrets(inputStream: InputStream): Secrets {
         val dexFile = inputStream.readBytes()
         val byteOrder = ByteOrder.BIG_ENDIAN
         val vbdmSubstitutionCipher = dexFile.sliceArray(VBDM_SUBSTITUTION_CIPHER_IDX until VBDM_SUBSTITUTION_CIPHER_IDX+(16*4)).toIntArray(byteOrder)
         val beSubstitutionCipher = dexFile.sliceArray(BE_SUBSTITUTION_CIPHER_IDX until BE_SUBSTITUTION_CIPHER_IDX+(16*4)).toIntArray(byteOrder)
         val aesKey = dexFile.sliceArray(AES_KEY_IDX until AES_KEY_IDX+24).toString(StandardCharsets.UTF_8)
-        val secretsByDevices = mapOf(
-            Pair(DeviceType.VitalSeriesDeviceType, buildSecrets(dexFile, VBDM_HMAC_KEY_1_IDX, VBDM_HMAC_KEY_2_IDX, aesKey, vbdmSubstitutionCipher)),
-            Pair(DeviceType.VitalBraceletBEDeviceType, buildSecrets(dexFile, BE_HMAC_KEY_1_IDX, BE_HMAC_KEY_2_IDX, aesKey, beSubstitutionCipher)),
-            Pair(DeviceType.VitalCharactersDeviceType, buildSecrets(dexFile, VBC_HMAC_KEY_1_IDX, VBC_HMAC_KEY_2_IDX, aesKey, vbdmSubstitutionCipher)),
-        )
-        return secretsByDevices
+        return Secrets.newBuilder()
+            .setAesKey(aesKey)
+            .addAllVbCipher(vbdmSubstitutionCipher.toList())
+            .addAllBeCipher(beSubstitutionCipher.toList())
+            .setVbdmHmacKeys(getHmac(dexFile, VBDM_HMAC_KEY_1_IDX, VBDM_HMAC_KEY_2_IDX))
+            .setVbcHmacKeys(getHmac(dexFile, VBC_HMAC_KEY_1_IDX, VBC_HMAC_KEY_2_IDX))
+            .setBeHmacKeys(getHmac(dexFile, BE_HMAC_KEY_1_IDX, BE_HMAC_KEY_2_IDX))
+            .build()
     }
 
-    private fun buildSecrets(dexFile: ByteArray, hmacKeyIdx1: Int, hmacKeyIdx2: Int, aesKey: String, substitutionCipher: IntArray): Secrets {
+    private fun getHmac(dexFile: ByteArray, hmacKeyIdx1: Int, hmacKeyIdx2: Int): HmacKeys {
         val hmacKey1 = dexFile.sliceArray(hmacKeyIdx1 until hmacKeyIdx1+24).toString(StandardCharsets.UTF_8)
         val hmacKey2 = dexFile.sliceArray(hmacKeyIdx2 until hmacKeyIdx2+24).toString(StandardCharsets.UTF_8)
-        return Secrets(hmacKey1, hmacKey2, aesKey, substitutionCipher)
+        return HmacKeys.newBuilder()
+            .setHmacKey1(hmacKey1)
+            .setHmacKey2(hmacKey2)
+            .build()
     }
 
     @OptIn(ExperimentalStdlibApi::class)
-    private fun verifySecretCorrectness(deviceToSecrets: Map<UShort, Secrets>) {
-        for (keyValue in deviceToSecrets) {
+    private fun verifySecretCorrectness(secrets: Secrets) {
+        val deviceToCryptographicTransformers = secrets.getCryptographicTransformerMap()
+        for (keyValue in deviceToCryptographicTransformers) {
             when(keyValue.key) {
-                DeviceType.VitalBraceletBEDeviceType -> {
-                    val result = keyValue.value.toCryptographicTransformer().createNfcPassword(
-                        TEST_TAG
-                    )
-                    if( result.toHexString() != BE_TEST_TAG_PASSWORD) {
-                        throw InvalidKeyException("Secrets were loaded, but were unsuccessful at generating the test password: ${result.toHexString()}")
-                    }
-                }
-                DeviceType.VitalCharactersDeviceType -> {
-                    val result = keyValue.value.toCryptographicTransformer().createNfcPassword(
-                        TEST_TAG
-                    )
-                    if( result.toHexString() != VBC_TEST_TAG_PASSWORD) {
-                        throw InvalidKeyException("Secrets were loaded, but were unsuccessful at generating the test password: ${result.toHexString()}")
-                    }
-                }
-                DeviceType.VitalSeriesDeviceType -> {
-                    val result = keyValue.value.toCryptographicTransformer().createNfcPassword(
-                        TEST_TAG
-                    )
-                    if( result.toHexString() != VBDM_TEST_TAG_PASSWORD) {
-                        throw InvalidKeyException("Secrets were loaded, but were unsuccessful at generating the test password: ${result.toHexString()}")
-                    }
-                }
+                DeviceType.VitalBraceletBEDeviceType -> assertBuildsCorrectPassword(keyValue.value, BE_TEST_TAG_PASSWORD)
+                DeviceType.VitalCharactersDeviceType -> assertBuildsCorrectPassword(keyValue.value, VBC_TEST_TAG_PASSWORD)
+                DeviceType.VitalSeriesDeviceType -> assertBuildsCorrectPassword(keyValue.value, VBDM_TEST_TAG_PASSWORD)
             }
         }
     }
+
+    @OptIn(ExperimentalStdlibApi::class)
+    private fun assertBuildsCorrectPassword(cryptographicTransformer: CryptographicTransformer, expectedPassword: String) {
+        val result = cryptographicTransformer.createNfcPassword(
+            TEST_TAG
+        )
+        if( result.toHexString() != expectedPassword) {
+            throw InvalidKeyException("Secrets were loaded, but were unsuccessful at generating the test password")
+        }
+    }
 }
 
 fun ByteArray.toIntArray(byteOrder: ByteOrder): IntArray {

@@ 1,9 0,0 @@
-package com.github.nacabaro.vbhelper.source
-
-import com.github.cfogrady.vbnfc.CryptographicTransformer
-
-data class Secrets(val hmacKey1: String, val hmacKey2: String, val aesKey: String, val substitutionCipher: IntArray) {
-    fun toCryptographicTransformer(): CryptographicTransformer {
-        return CryptographicTransformer(hmacKey1, hmacKey2, aesKey, substitutionCipher)
-    }
-}

@@ 1,7 1,8 @@
 package com.github.nacabaro.vbhelper.source
 
+import com.github.nacabaro.vbhelper.source.proto.Secrets
 import java.io.InputStream
 
 fun interface SecretsImporter {
-    fun importSecrets(inputStream: InputStream): Map<UShort, Secrets>
+    fun importSecrets(inputStream: InputStream): Secrets
 }=
\ No newline at end of file

@@ 0,0 1,11 @@
+package com.github.nacabaro.vbhelper.source
+
+import com.github.nacabaro.vbhelper.source.proto.Secrets
+import kotlinx.coroutines.flow.Flow
+
+interface SecretsRepository {
+    val secretsFlow: Flow<Secrets>
+
+    suspend fun getSecrets(): Secrets
+    suspend fun updateSecrets(secrets: Secrets)
+}<
\ No newline at end of file

@@ 0,0 1,24 @@
+package com.github.nacabaro.vbhelper.source
+
+import androidx.datastore.core.CorruptionException
+import androidx.datastore.core.Serializer
+import com.github.nacabaro.vbhelper.source.proto.Secrets
+import com.google.protobuf.InvalidProtocolBufferException
+import java.io.InputStream
+import java.io.OutputStream
+
+object SecretsSerializer: Serializer<Secrets> {
+    override val defaultValue = Secrets.getDefaultInstance()
+
+    override suspend fun readFrom(input: InputStream): Secrets {
+        try {
+            return Secrets.parseFrom(input)
+        } catch (exception: InvalidProtocolBufferException) {
+            throw CorruptionException("Cannot read proto.", exception)
+        }
+    }
+
+    override suspend fun writeTo(t: Secrets, output: OutputStream) {
+        t.writeTo(output)
+    }
+}<
\ No newline at end of file

@@ 0,0 1,19 @@
+syntax = "proto3";
+
+option java_package = "com.github.nacabaro.vbhelper.source.proto";
+option java_multiple_files = true;
+
+message Secrets {
+  string aes_key = 1;
+  repeated int32 vb_cipher = 2;
+  repeated int32 be_cipher = 3;
+
+  message HmacKeys {
+    string hmac_key_1 = 1;
+    string hmac_key_2 = 2;
+  }
+  HmacKeys vbdm_hmac_keys = 4;
+  HmacKeys vbc_hmac_keys = 5;
+  HmacKeys be_hmac_keys = 6;
+
+}<
\ No newline at end of file

@@ 1,6 1,6 @@
 package com.github.nacabaro.vbhelper.source
 
-import com.github.cfogrady.vbnfc.data.DeviceType
+import com.github.nacabaro.vbhelper.source.proto.Secrets
 import org.junit.Assert
 import org.junit.Test
 import java.io.ByteArrayInputStream


@@ 14,15 14,18 @@ import java.util.zip.ZipOutputStream
 class ApkSecretsImporterTest {
 
     @Test
-    fun testThatRealImportSecretsHasAllDeviceTypes() {
+    fun testThatRealImportSecretsPasses() {
         val apkFileSecretsImporter = ApkSecretsImporter()
         val url = getAndAssertApkFile()
         val file = File(url.path)
         file.inputStream().use {
-            val deviceIdToSecrets = apkFileSecretsImporter.importSecrets(it)
-            Assert.assertNotNull("BE Device Type", deviceIdToSecrets[DeviceType.VitalBraceletBEDeviceType])
-            Assert.assertNotNull("VBDM Device Type", deviceIdToSecrets[DeviceType.VitalSeriesDeviceType])
-            Assert.assertNotNull("VBC Device Type", deviceIdToSecrets[DeviceType.VitalCharactersDeviceType])
+            val secrets = apkFileSecretsImporter.importSecrets(it)
+            Assert.assertEquals("Cipher size isn't correct", 16, secrets.vbCipherCount)
+            Assert.assertEquals("BE Cipher size isn't correct", 16, secrets.beCipherCount)
+            Assert.assertFalse("AES Key is empty", secrets.aesKey.isEmpty())
+            assertHmacKeysArePopulated("VBDM", secrets.vbdmHmacKeys)
+            assertHmacKeysArePopulated("VBC", secrets.vbcHmacKeys)
+            assertHmacKeysArePopulated("BE", secrets.beHmacKeys)
         }
     }
 


@@ 34,7 37,7 @@ class ApkSecretsImporterTest {
             val inputStreamContents = it.readAllBytes()
             Assert.assertTrue("Unexpected file contents received by DexSecretsImporter", inputStreamContents.contentEquals(expectedDexContents))
             foundFile = true
-            emptyMap()
+            Secrets.newBuilder().build()
         }
         val apkBytes = constructTestApk(expectedDexContents)
         ByteArrayInputStream(apkBytes).use {


@@ 70,4 73,4 @@ class ApkSecretsImporterTest {
         }
         return url!!
     }
-}>
\ No newline at end of file
+}

@@ 1,6 1,6 @@
 package com.github.nacabaro.vbhelper.source
 
-import com.github.cfogrady.vbnfc.data.DeviceType
+import com.github.nacabaro.vbhelper.source.proto.Secrets.HmacKeys
 import org.junit.Assert
 import org.junit.Test
 import java.io.ByteArrayInputStream


@@ 10,18 10,26 @@ import java.nio.ByteOrder
 import java.security.InvalidKeyException
 
 
+fun assertHmacKeysArePopulated(msg: String, hmacKeys: HmacKeys) {
+    Assert.assertFalse("$msg hmacKey1 is empty", hmacKeys.hmacKey1.isEmpty())
+    Assert.assertFalse("$msg hmacKey2 is empty", hmacKeys.hmacKey2.isEmpty())
+}
+
 class DexFileSecretsImporterTest {
 
     @Test
-    fun testThatImportSecretsHasAllDeviceTypes() {
+    fun testThatImportSecretsIsPopulated() {
         val dexFileSecretsImporter = DexFileSecretsImporter()
         val url = getAndAssertClassesDexFile()
         val file = File(url.path)
         file.inputStream().use {
-            val deviceIdToSecrets = dexFileSecretsImporter.importSecrets(it)
-            Assert.assertNotNull("BE Device Type", deviceIdToSecrets[DeviceType.VitalBraceletBEDeviceType])
-            Assert.assertNotNull("VBDM Device Type", deviceIdToSecrets[DeviceType.VitalSeriesDeviceType])
-            Assert.assertNotNull("VBC Device Type", deviceIdToSecrets[DeviceType.VitalCharactersDeviceType])
+            val secrets = dexFileSecretsImporter.importSecrets(it)
+            Assert.assertEquals("Cipher size isn't correct", 16, secrets.vbCipherCount)
+            Assert.assertEquals("BE Cipher size isn't correct", 16, secrets.beCipherCount)
+            Assert.assertFalse("AES Key is empty", secrets.aesKey.isEmpty())
+            assertHmacKeysArePopulated("VBDM", secrets.vbdmHmacKeys)
+            assertHmacKeysArePopulated("VBC", secrets.vbcHmacKeys)
+            assertHmacKeysArePopulated("BE", secrets.beHmacKeys)
         }
     }
 

@@ 3,4 3,10 @@ plugins {
     alias(libs.plugins.android.application) apply false
     alias(libs.plugins.kotlin.android) apply false
     alias(libs.plugins.kotlin.compose) apply false
+}
+
+buildscript {
+    dependencies {
+        classpath(libs.protobuf.gradle.plugin)
+    }
 }=
\ No newline at end of file

@@ 1,5 1,6 @@
 [versions]
 agp = "8.7.3"
+datastore = "1.1.1"
 kotlin = "2.0.0"
 coreKtx = "1.15.0"
 junit = "4.13.2"


@@ 8,12 9,15 @@ espressoCore = "3.6.1"
 lifecycleRuntimeKtx = "2.8.7"
 activityCompose = "1.9.3"
 composeBom = "2024.04.01"
+protobufGradlePlugin = "0.9.4"
+protobufJavalite = "4.27.0"
 roomRuntime = "2.6.1"
 vbNfcReader = "0.1.0"
 dimReader = "2.1.0"
 
 [libraries]
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
+androidx-datastore = { module = "androidx.datastore:datastore", version.ref = "datastore" }
 androidx-room-compiler = { module = "androidx.room:room-compiler", version.ref = "roomRuntime" }
 androidx-room-runtime = { module = "androidx.room:room-runtime", version.ref = "roomRuntime" }
 junit = { group = "junit", name = "junit", version.ref = "junit" }


@@ 29,6 33,8 @@ androidx-ui-tooling-preview = { group = "androidx.compose.ui", name = "ui-toolin
 androidx-ui-test-manifest = { group = "androidx.compose.ui", name = "ui-test-manifest" }
 androidx-ui-test-junit4 = { group = "androidx.compose.ui", name = "ui-test-junit4" }
 androidx-material3 = { group = "androidx.compose.material3", name = "material3" }
+protobuf-gradle-plugin = { module = "com.google.protobuf:protobuf-gradle-plugin", version.ref = "protobufGradlePlugin" }
+protobuf-javalite = { module = "com.google.protobuf:protobuf-javalite", version.ref = "protobufJavalite" }
 vb-nfc-reader = { module = "com.github.cfogrady:vb-nfc-reader", version.ref = "vbNfcReader" }
 dim-reader = { module = "com.github.cfogrady:vb-dim-reader", version.ref = "dimReader" }