Add `KeyPair` and `KeyManager` to manage keys in the app (#1487)

Co-authored-by: Harsh Shandilya <me@msfjarvis.dev>

18 files changed, 673 insertions, 8 deletions

diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index 994a5ca0..ffe8acae 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -2,13 +2,9 @@ on: [pull_request]
 
 name: Check pull request
 jobs:
-  test-pr:
+  unit-tests:
     runs-on: ubuntu-latest
     steps:
-
-    #- name: Auto-cancel redundant workflow run
-    #  uses: technote-space/auto-cancel-redundant-workflow@f9dfa1c127a520e4d71b92892850f861fb861206
-
     - name: Check if relevant files have changed
       uses: actions/github-script@a3e7071a34d7e1f219a8a4de9a5e0a34d1ee1293
       id: service-changed
@@ -43,8 +39,6 @@ jobs:
       uses: actions/checkout@5a4ac9002d0be2fb38bd78e4b4dbde5606d7042f
       with:
         fetch-depth: 0
-      #with:
-      #  ref: refs/pull/${{ github.event.pull_request.number }}/merge
 
     - name: Copy CI gradle.properties
       if: ${{ steps.service-changed.outputs.result == 'true' }}
@@ -62,3 +56,81 @@ jobs:
       with:
           name: Test report
           path: app/build/reports
+
+  run-screenshot-tests:
+    runs-on: macOS-latest
+    steps:
+    - name: Check if relevant files have changed
+      uses: actions/github-script@a3e7071a34d7e1f219a8a4de9a5e0a34d1ee1293
+      id: service-changed
+      with:
+        result-encoding: string
+        script: |
+          const result = await github.pulls.listFiles({
+            owner: context.payload.repository.owner.login,
+            repo: context.payload.repository.name,
+            pull_number: context.payload.number,
+            per_page: 100
+          })
+          const files = result.data.filter(file =>
+            // We wanna run this if the PR workflow is modified
+            (file.filename.endsWith(".yml") && !file.filename.endsWith("pull_request.yml")) ||
+            // Changes in Markdown files don't need tests
+            file.filename.endsWith(".md") ||
+            // Changes to fastlane metadata aren't covered by tests
+            file.filename.startsWith("fastlane/")
+          )
+          // If filtered file count and source file count is equal, it means all files
+          // in this PR are skip-worthy.
+          return files.length != result.data.length
+
+    - uses: actions/cache@c64c572235d810460d0d6876e9c705ad5002b353
+      if: ${{ steps.service-changed.outputs.result == 'true' }}
+      id: avd-cache
+      with:
+        path: |
+          ~/.android/avd/*
+          ~/.android/adb*
+        key: avd-23
+
+    - uses: actions/setup-java@d202f5dbf7256730fb690ec59f6381650114feb2
+      if: ${{ steps.service-changed.outputs.result == 'true' }}
+      with:
+        java-version: '11'
+
+    - name: Checkout repository
+      if: ${{ steps.service-changed.outputs.result == 'true' }}
+      uses: actions/checkout@5a4ac9002d0be2fb38bd78e4b4dbde5606d7042f
+      with:
+        fetch-depth: 0
+
+    - name: Copy CI gradle.properties
+      if: ${{ steps.service-changed.outputs.result == 'true' }}
+      run: mkdir -p ~/.gradle ; cp .github/ci-gradle.properties ~/.gradle/gradle.properties
+
+    - name: Create AVD and generate snapshot for caching
+      uses: reactivecircus/android-emulator-runner@5de26e4bd23bf523e8a4b7f077df8bfb8e52b50e
+      if: ${{ steps.avd-cache.outputs.cache-hit != 'true' }}
+      with:
+        api-level: 23
+        force-avd-creation: false
+        emulator-options: -no-window -gpu swiftshader_indirect -noaudio -no-boot-anim -camera-back none
+        disable-animations: false
+        script: echo "Generated AVD snapshot for caching"
+
+    - name: Run screenshot tests
+      uses: reactivecircus/android-emulator-runner@5de26e4bd23bf523e8a4b7f077df8bfb8e52b50e
+      if: ${{ steps.service-changed.outputs.result == 'true' }}
+      with:
+        api-level: 23
+        force-avd-creation: false
+        emulator-options: -no-snapshot-save -no-window -gpu swiftshader_indirect -noaudio -no-boot-anim -camera-back none
+        disable-animations: true
+        script: ./gradlew connectedCheck -PslimTests
+
+    - name: (Fail-only) upload test report
+      if: failure()
+      uses: actions/upload-artifact@27121b0bdffd731efa15d66772be8dc71245d074
+      with:
+          name: Test report
+          path: app/build/reports
diff --git a/buildSrc/src/main/java/BaseProjectConfig.kt b/buildSrc/src/main/java/BaseProjectConfig.kt
index f3a33713..f9687c3c 100644
--- a/buildSrc/src/main/java/BaseProjectConfig.kt
+++ b/buildSrc/src/main/java/BaseProjectConfig.kt
@@ -121,6 +121,7 @@ internal fun TestedExtension.configureCommonAndroidOptions() {
   sourceSets {
     named("main") { java.srcDirs("src/main/kotlin") }
     named("test") { java.srcDirs("src/test/kotlin") }
+    named("androidTest") { java.srcDirs("src/androidTest/kotlin") }
   }
 
   packagingOptions {
@@ -128,6 +129,8 @@ internal fun TestedExtension.configureCommonAndroidOptions() {
     resources.excludes.add("**/*.txt")
     resources.excludes.add("**/*.kotlin_module")
     resources.excludes.add("**/plugin.properties")
+    resources.excludes.add("**/META-INF/AL2.0")
+    resources.excludes.add("**/META-INF/LGPL2.1")
   }
 
   compileOptions {
diff --git a/buildSrc/src/main/java/SlimTests.kt b/buildSrc/src/main/java/SlimTests.kt
index e06c7c8c..4057032b 100644
--- a/buildSrc/src/main/java/SlimTests.kt
+++ b/buildSrc/src/main/java/SlimTests.kt
@@ -21,7 +21,10 @@ internal fun Project.configureSlimTests() {
   if (providers.gradleProperty(SLIM_TESTS_PROPERTY).forUseAtConfigurationTime().isPresent) {
     // disable unit test tasks on the release build type for Android Library projects
     extensions.findByType<LibraryAndroidComponentsExtension>()?.run {
-      beforeVariants(selector().withBuildType(BuildType.RELEASE.name)) { it.enableUnitTest = false }
+      beforeVariants(selector().withBuildType(BuildType.RELEASE.name)) {
+        it.enableUnitTest = false
+        it.enableAndroidTest = false
+      }
     }
 
     // disable unit test tasks on the release build type and free flavor for Android Application
@@ -30,6 +33,7 @@ internal fun Project.configureSlimTests() {
       beforeVariants(selector().withBuildType(BuildType.RELEASE.name)) { it.enableUnitTest = false }
       beforeVariants(selector().withFlavor(FlavorDimensions.FREE to ProductFlavors.NON_FREE)) {
         it.enableUnitTest = false
+        it.enableAndroidTest = false
       }
     }
   }
diff --git a/crypto-common/api/crypto-common.api b/crypto-common/api/crypto-common.api
index 7493379c..6468ea9b 100644
--- a/crypto-common/api/crypto-common.api
+++ b/crypto-common/api/crypto-common.api
@@ -1,6 +1,63 @@
+public abstract class dev/msfjarvis/aps/data/crypto/CryptoException : java/lang/Exception {
+	public synthetic fun <init> (Ljava/lang/String;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun <init> (Ljava/lang/String;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
+}
+
 public abstract interface class dev/msfjarvis/aps/data/crypto/CryptoHandler {
 	public abstract fun canHandle (Ljava/lang/String;)Z
 	public abstract fun decrypt (Ljava/lang/String;[B[B)[B
 	public abstract fun encrypt (Ljava/lang/String;[B)[B
 }
 
+public abstract interface class dev/msfjarvis/aps/data/crypto/KeyManager {
+	public abstract fun addKey (Ldev/msfjarvis/aps/data/crypto/KeyPair;ZLkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public abstract fun canHandle (Ljava/lang/String;)Z
+	public abstract fun getAllKeys (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public abstract fun getKeyById (Ljava/lang/String;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public abstract fun removeKey (Ldev/msfjarvis/aps/data/crypto/KeyPair;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+}
+
+public final class dev/msfjarvis/aps/data/crypto/KeyManager$DefaultImpls {
+	public static synthetic fun addKey$default (Ldev/msfjarvis/aps/data/crypto/KeyManager;Ldev/msfjarvis/aps/data/crypto/KeyPair;ZLkotlin/coroutines/Continuation;ILjava/lang/Object;)Ljava/lang/Object;
+}
+
+public abstract class dev/msfjarvis/aps/data/crypto/KeyManagerException : dev/msfjarvis/aps/data/crypto/CryptoException {
+	public synthetic fun <init> (Ljava/lang/String;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun <init> (Ljava/lang/String;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
+}
+
+public final class dev/msfjarvis/aps/data/crypto/KeyManagerException$KeyAlreadyExistsException : dev/msfjarvis/aps/data/crypto/KeyManagerException {
+	public fun <init> (Ljava/lang/String;)V
+}
+
+public final class dev/msfjarvis/aps/data/crypto/KeyManagerException$KeyDeletionFailedException : dev/msfjarvis/aps/data/crypto/KeyManagerException {
+	public static final field INSTANCE Ldev/msfjarvis/aps/data/crypto/KeyManagerException$KeyDeletionFailedException;
+}
+
+public final class dev/msfjarvis/aps/data/crypto/KeyManagerException$KeyDirectoryUnavailableException : dev/msfjarvis/aps/data/crypto/KeyManagerException {
+	public static final field INSTANCE Ldev/msfjarvis/aps/data/crypto/KeyManagerException$KeyDirectoryUnavailableException;
+}
+
+public final class dev/msfjarvis/aps/data/crypto/KeyManagerException$KeyNotFoundException : dev/msfjarvis/aps/data/crypto/KeyManagerException {
+	public fun <init> (Ljava/lang/String;)V
+}
+
+public final class dev/msfjarvis/aps/data/crypto/KeyManagerException$NoKeysAvailableException : dev/msfjarvis/aps/data/crypto/KeyManagerException {
+	public static final field INSTANCE Ldev/msfjarvis/aps/data/crypto/KeyManagerException$NoKeysAvailableException;
+}
+
+public abstract interface class dev/msfjarvis/aps/data/crypto/KeyPair {
+	public abstract fun getKeyId ()Ljava/lang/String;
+	public abstract fun getPrivateKey ()[B
+	public abstract fun getPublicKey ()[B
+}
+
+public abstract class dev/msfjarvis/aps/data/crypto/KeyPairException : dev/msfjarvis/aps/data/crypto/CryptoException {
+	public synthetic fun <init> (Ljava/lang/String;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun <init> (Ljava/lang/String;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
+}
+
+public final class dev/msfjarvis/aps/data/crypto/KeyPairException$PrivateKeyUnavailableException : dev/msfjarvis/aps/data/crypto/KeyPairException {
+	public static final field INSTANCE Ldev/msfjarvis/aps/data/crypto/KeyPairException$PrivateKeyUnavailableException;
+}
+
diff --git a/crypto-common/build.gradle.kts b/crypto-common/build.gradle.kts
index c1f3eef8..44323900 100644
--- a/crypto-common/build.gradle.kts
+++ b/crypto-common/build.gradle.kts
@@ -6,3 +6,5 @@ plugins {
   kotlin("jvm")
   `aps-plugin`
 }
+
+dependencies { implementation(libs.thirdparty.kotlinResult) }
diff --git a/crypto-common/src/main/kotlin/dev/msfjarvis/aps/data/crypto/CryptoException.kt b/crypto-common/src/main/kotlin/dev/msfjarvis/aps/data/crypto/CryptoException.kt
new file mode 100644
index 00000000..6a73d381
--- /dev/null
+++ b/crypto-common/src/main/kotlin/dev/msfjarvis/aps/data/crypto/CryptoException.kt
@@ -0,0 +1,19 @@
+package dev.msfjarvis.aps.data.crypto
+
+public sealed class CryptoException(message: String? = null) : Exception(message)
+
+public sealed class KeyPairException(message: String? = null) : CryptoException(message) {
+  public object PrivateKeyUnavailableException :
+    KeyPairException("Key object does not have a private sub-key")
+}
+
+public sealed class KeyManagerException(message: String? = null) : CryptoException(message) {
+  public object NoKeysAvailableException : KeyManagerException("No keys were found")
+  public object KeyDirectoryUnavailableException :
+    KeyManagerException("Key directory does not exist")
+  public object KeyDeletionFailedException : KeyManagerException("Couldn't delete the key file")
+  public class KeyNotFoundException(keyId: String) :
+    KeyManagerException("No key found with id: $keyId")
+  public class KeyAlreadyExistsException(keyId: String) :
+    KeyManagerException("Pre-existing key was found for $keyId but 'replace' is set to false")
+}
diff --git a/crypto-common/src/main/kotlin/dev/msfjarvis/aps/data/crypto/KeyManager.kt b/crypto-common/src/main/kotlin/dev/msfjarvis/aps/data/crypto/KeyManager.kt
new file mode 100644
index 00000000..b5ba881e
--- /dev/null
+++ b/crypto-common/src/main/kotlin/dev/msfjarvis/aps/data/crypto/KeyManager.kt
@@ -0,0 +1,19 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package dev.msfjarvis.aps.data.crypto
+
+import com.github.michaelbull.result.Result
+
+public interface KeyManager<T : KeyPair> {
+
+  public suspend fun addKey(key: T, replace: Boolean = false): Result<T, Throwable>
+  public suspend fun removeKey(key: T): Result<T, Throwable>
+  public suspend fun getKeyById(id: String): Result<T, Throwable>
+  public suspend fun getAllKeys(): Result<List<T>, Throwable>
+
+  /** Given a [fileName], return whether this instance can handle it. */
+  public fun canHandle(fileName: String): Boolean
+}
diff --git a/crypto-common/src/main/kotlin/dev/msfjarvis/aps/data/crypto/KeyPair.kt b/crypto-common/src/main/kotlin/dev/msfjarvis/aps/data/crypto/KeyPair.kt
new file mode 100644
index 00000000..e2362612
--- /dev/null
+++ b/crypto-common/src/main/kotlin/dev/msfjarvis/aps/data/crypto/KeyPair.kt
@@ -0,0 +1,14 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package dev.msfjarvis.aps.data.crypto
+
+/** Defines expectations for a keypair used in public key cryptography. */
+public interface KeyPair {
+
+  public fun getPrivateKey(): ByteArray
+  public fun getPublicKey(): ByteArray
+  public fun getKeyId(): String
+}
diff --git a/crypto-pgp/api/crypto-pgp.api b/crypto-pgp/api/crypto-pgp.api
index 2164360c..c9b2dde7 100644
--- a/crypto-pgp/api/crypto-pgp.api
+++ b/crypto-pgp/api/crypto-pgp.api
@@ -1,3 +1,21 @@
+public final class dev/msfjarvis/aps/data/crypto/GPGKeyManager : dev/msfjarvis/aps/data/crypto/KeyManager {
+	public fun <init> (Ljava/lang/String;Lkotlinx/coroutines/CoroutineDispatcher;)V
+	public fun addKey (Ldev/msfjarvis/aps/data/crypto/GPGKeyPair;ZLkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public synthetic fun addKey (Ldev/msfjarvis/aps/data/crypto/KeyPair;ZLkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public fun canHandle (Ljava/lang/String;)Z
+	public fun getAllKeys (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public fun getKeyById (Ljava/lang/String;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public fun removeKey (Ldev/msfjarvis/aps/data/crypto/GPGKeyPair;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public synthetic fun removeKey (Ldev/msfjarvis/aps/data/crypto/KeyPair;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+}
+
+public final class dev/msfjarvis/aps/data/crypto/GPGKeyPair : dev/msfjarvis/aps/data/crypto/KeyPair {
+	public fun <init> (Lcom/proton/Gopenpgp/crypto/Key;)V
+	public fun getKeyId ()Ljava/lang/String;
+	public fun getPrivateKey ()[B
+	public fun getPublicKey ()[B
+}
+
 public final class dev/msfjarvis/aps/data/crypto/GopenpgpCryptoHandler : dev/msfjarvis/aps/data/crypto/CryptoHandler {
 	public fun <init> ()V
 	public fun canHandle (Ljava/lang/String;)Z
diff --git a/crypto-pgp/build.gradle.kts b/crypto-pgp/build.gradle.kts
index 493062b6..95542b1c 100644
--- a/crypto-pgp/build.gradle.kts
+++ b/crypto-pgp/build.gradle.kts
@@ -2,14 +2,28 @@
  * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
  * SPDX-License-Identifier: GPL-3.0-only
  */
+
 plugins {
   id("com.android.library")
   kotlin("android")
   `aps-plugin`
 }
 
+android {
+  defaultConfig {
+    testApplicationId = "dev.msfjarvis.aps.cryptopgp.test"
+    testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+  }
+}
+
 dependencies {
   api(projects.cryptoCommon)
+  implementation(libs.androidx.annotation)
   implementation(libs.aps.gopenpgp)
   implementation(libs.dagger.hilt.core)
+  implementation(libs.kotlin.coroutines.core)
+  implementation(libs.thirdparty.kotlinResult)
+  androidTestImplementation(libs.bundles.testDependencies)
+  androidTestImplementation(libs.kotlin.coroutines.test)
+  androidTestImplementation(libs.bundles.androidTestDependencies)
 }
diff --git a/crypto-pgp/src/androidTest/kotlin/dev/msfjarvis/aps/crypto/GPGKeyManagerTest.kt b/crypto-pgp/src/androidTest/kotlin/dev/msfjarvis/aps/crypto/GPGKeyManagerTest.kt
new file mode 100644
index 00000000..80a13eb5
--- /dev/null
+++ b/crypto-pgp/src/androidTest/kotlin/dev/msfjarvis/aps/crypto/GPGKeyManagerTest.kt
@@ -0,0 +1,165 @@
+package dev.msfjarvis.aps.crypto
+
+import androidx.test.platform.app.InstrumentationRegistry
+import com.github.michaelbull.result.unwrap
+import com.github.michaelbull.result.unwrapError
+import com.proton.Gopenpgp.crypto.Key
+import dev.msfjarvis.aps.crypto.utils.CryptoConstants
+import dev.msfjarvis.aps.cryptopgp.test.R
+import dev.msfjarvis.aps.data.crypto.GPGKeyManager
+import dev.msfjarvis.aps.data.crypto.GPGKeyPair
+import dev.msfjarvis.aps.data.crypto.KeyManagerException
+import java.io.File
+import kotlin.test.assertEquals
+import kotlin.test.assertIs
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.TestCoroutineDispatcher
+import kotlinx.coroutines.test.runBlockingTest
+import org.junit.After
+import org.junit.Before
+import org.junit.Test
+
+@OptIn(ExperimentalCoroutinesApi::class)
+public class GPGKeyManagerTest {
+
+  private val testCoroutineDispatcher = TestCoroutineDispatcher()
+  private lateinit var gpgKeyManager: GPGKeyManager
+  private lateinit var key: GPGKeyPair
+
+  @Before
+  public fun setup() {
+    gpgKeyManager = GPGKeyManager(getFilesDir().absolutePath, testCoroutineDispatcher)
+    key = GPGKeyPair(Key(getKey()))
+  }
+
+  @After
+  public fun tearDown() {
+    val filesDir = getFilesDir()
+    val keysDir = File(filesDir, GPGKeyManager.KEY_DIR_NAME)
+
+    keysDir.deleteRecursively()
+  }
+
+  @Test
+  public fun testAddingKey() {
+    runBlockingTest {
+      // Check if the key id returned is correct
+      val keyId = gpgKeyManager.addKey(key).unwrap().getKeyId()
+      assertEquals(CryptoConstants.KEY_ID, keyId)
+
+      // Check if the keys directory have one file
+      val keysDir = File(getFilesDir(), GPGKeyManager.KEY_DIR_NAME)
+      assertEquals(1, keysDir.list()?.size)
+
+      // Check if the file name is correct
+      val keyFile = keysDir.listFiles()?.first()
+      assertEquals(keyFile?.name, "$keyId.${GPGKeyManager.KEY_EXTENSION}")
+    }
+  }
+
+  @Test
+  public fun testAddingKeyWithoutReplaceFlag() {
+    runBlockingTest {
+      // Check adding the keys twice
+      gpgKeyManager.addKey(key, false).unwrap()
+      val error = gpgKeyManager.addKey(key, false).unwrapError()
+
+      assertIs<KeyManagerException.KeyAlreadyExistsException>(error)
+    }
+  }
+
+  @Test
+  public fun testAddingKeyWithReplaceFlag() {
+    runBlockingTest {
+      // Check adding the keys twice
+      gpgKeyManager.addKey(key, true).unwrap()
+      val keyId = gpgKeyManager.addKey(key, true).unwrap().getKeyId()
+
+      assertEquals(CryptoConstants.KEY_ID, keyId)
+    }
+  }
+
+  @Test
+  public fun testRemovingKey() {
+    runBlockingTest {
+      // Add key using KeyManager
+      gpgKeyManager.addKey(key).unwrap()
+
+      // Check if the key id returned is correct
+      val keyId = gpgKeyManager.removeKey(key).unwrap().getKeyId()
+      assertEquals(CryptoConstants.KEY_ID, keyId)
+
+      // Check if the keys directory have 0 files
+      val keysDir = File(getFilesDir(), GPGKeyManager.KEY_DIR_NAME)
+      assertEquals(0, keysDir.list()?.size)
+    }
+  }
+
+  @Test
+  public fun testGetExistingKey() {
+    runBlockingTest {
+      // Add key using KeyManager
+      gpgKeyManager.addKey(key).unwrap()
+
+      // Check returned key id matches the expected id and the created key id
+      val returnedKeyPair = gpgKeyManager.getKeyById(key.getKeyId()).unwrap()
+      assertEquals(CryptoConstants.KEY_ID, key.getKeyId())
+      assertEquals(key.getKeyId(), returnedKeyPair.getKeyId())
+    }
+  }
+
+  @Test
+  public fun testGetNonExistentKey() {
+    runBlockingTest {
+      // Add key using KeyManager
+      gpgKeyManager.addKey(key).unwrap()
+
+      val randomKeyId = "0x123456789"
+
+      // Check returned key
+      val error = gpgKeyManager.getKeyById(randomKeyId).unwrapError()
+      assertIs<KeyManagerException.KeyNotFoundException>(error)
+      assertEquals("No key found with id: $randomKeyId", error.message)
+    }
+  }
+
+  @Test
+  public fun testFindKeysWithoutAdding() {
+    runBlockingTest {
+      // Check returned key
+      val error = gpgKeyManager.getKeyById("0x123456789").unwrapError()
+      assertIs<KeyManagerException.NoKeysAvailableException>(error)
+      assertEquals("No keys were found", error.message)
+    }
+  }
+
+  @Test
+  public fun testGettingAllKeys() {
+    runBlockingTest {
+      // TODO: Should we check for more than 1 keys?
+      // Check if KeyManager returns no key
+      val noKeyList = gpgKeyManager.getAllKeys().unwrap()
+      assertEquals(0, noKeyList.size)
+
+      // Add key using KeyManager
+      gpgKeyManager.addKey(key).unwrap()
+
+      // Check if KeyManager returns one key
+      val singleKeyList = gpgKeyManager.getAllKeys().unwrap()
+      assertEquals(1, singleKeyList.size)
+    }
+  }
+
+  private companion object {
+
+    fun getFilesDir(): File = InstrumentationRegistry.getInstrumentation().context.filesDir
+
+    fun getKey(): String =
+      InstrumentationRegistry.getInstrumentation()
+        .context
+        .resources
+        .openRawResource(R.raw.private_key)
+        .readBytes()
+        .decodeToString()
+  }
+}
diff --git a/crypto-pgp/src/androidTest/kotlin/dev/msfjarvis/aps/crypto/GPGKeyPairTest.kt b/crypto-pgp/src/androidTest/kotlin/dev/msfjarvis/aps/crypto/GPGKeyPairTest.kt
new file mode 100644
index 00000000..2340d9a5
--- /dev/null
+++ b/crypto-pgp/src/androidTest/kotlin/dev/msfjarvis/aps/crypto/GPGKeyPairTest.kt
@@ -0,0 +1,52 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package dev.msfjarvis.aps.crypto
+
+import androidx.test.platform.app.InstrumentationRegistry
+import com.proton.Gopenpgp.crypto.Key
+import dev.msfjarvis.aps.crypto.utils.CryptoConstants
+import dev.msfjarvis.aps.cryptopgp.test.R
+import dev.msfjarvis.aps.data.crypto.GPGKeyPair
+import dev.msfjarvis.aps.data.crypto.KeyPairException
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+import org.junit.Test
+
+public class GPGKeyPairTest {
+
+  @Test
+  public fun testIfKeyIdIsCorrect() {
+    val gpgKey = Key(getKey())
+    val keyPair = GPGKeyPair(gpgKey)
+
+    assertEquals(CryptoConstants.KEY_ID, keyPair.getKeyId())
+  }
+
+  @Test
+  public fun testBuildingKeyPairWithoutPrivateKey() {
+    assertFailsWith<KeyPairException.PrivateKeyUnavailableException>(
+      "GPGKeyPair does not have a private sub key"
+    ) {
+      // Get public key object from private key
+      val gpgKey = Key(getKey()).toPublic()
+      // Try creating a KeyPair from public key
+      val keyPair = GPGKeyPair(gpgKey)
+
+      keyPair.getPrivateKey()
+    }
+  }
+
+  private companion object {
+
+    fun getKey(): String =
+      InstrumentationRegistry.getInstrumentation()
+        .context
+        .resources
+        .openRawResource(R.raw.private_key)
+        .readBytes()
+        .decodeToString()
+  }
+}
diff --git a/crypto-pgp/src/androidTest/kotlin/dev/msfjarvis/aps/crypto/utils/CryptoConstants.kt b/crypto-pgp/src/androidTest/kotlin/dev/msfjarvis/aps/crypto/utils/CryptoConstants.kt
new file mode 100644
index 00000000..873f7105
--- /dev/null
+++ b/crypto-pgp/src/androidTest/kotlin/dev/msfjarvis/aps/crypto/utils/CryptoConstants.kt
@@ -0,0 +1,14 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package dev.msfjarvis.aps.crypto.utils
+
+internal object CryptoConstants {
+  internal const val KEY_PASSPHRASE = "hunter2"
+  internal const val PLAIN_TEXT = "encryption worthy content"
+  internal const val KEY_NAME = "John Doe"
+  internal const val KEY_EMAIL = "john.doe@example.com"
+  internal const val KEY_ID = "04ace699d5b15b7e"
+}
diff --git a/crypto-pgp/src/androidTest/res/raw/private_key b/crypto-pgp/src/androidTest/res/raw/private_key
new file mode 100644
index 00000000..5a4f436c
--- /dev/null
+++ b/crypto-pgp/src/androidTest/res/raw/private_key
@@ -0,0 +1,18 @@
+-----BEGIN PGP PRIVATE KEY BLOCK-----
+Version: GopenPGP 2.1.9
+Comment: https://gopenpgp.org
+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+=Sfsa
+-----END PGP PRIVATE KEY BLOCK-----
\ No newline at end of file
diff --git a/crypto-pgp/src/main/kotlin/dev/msfjarvis/aps/data/crypto/GPGKeyManager.kt b/crypto-pgp/src/main/kotlin/dev/msfjarvis/aps/data/crypto/GPGKeyManager.kt
new file mode 100644
index 00000000..478d2700
--- /dev/null
+++ b/crypto-pgp/src/main/kotlin/dev/msfjarvis/aps/data/crypto/GPGKeyManager.kt
@@ -0,0 +1,95 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package dev.msfjarvis.aps.data.crypto
+
+import androidx.annotation.VisibleForTesting
+import com.github.michaelbull.result.Result
+import com.github.michaelbull.result.runCatching
+import com.proton.Gopenpgp.crypto.Crypto
+import java.io.File
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.withContext
+
+public class GPGKeyManager(filesDir: String, private val dispatcher: CoroutineDispatcher) :
+  KeyManager<GPGKeyPair> {
+
+  private val keyDir = File(filesDir, KEY_DIR_NAME)
+
+  override suspend fun addKey(key: GPGKeyPair, replace: Boolean): Result<GPGKeyPair, Throwable> =
+    withContext(dispatcher) {
+      runCatching {
+        if (!keyDirExists()) throw KeyManagerException.KeyDirectoryUnavailableException
+        val keyFile = File(keyDir, "${key.getKeyId()}.$KEY_EXTENSION")
+        if (keyFile.exists()) {
+          // Check for replace flag first and if it is false, throw an error
+          if (!replace) throw KeyManagerException.KeyAlreadyExistsException(key.getKeyId())
+          if (!keyFile.delete()) throw KeyManagerException.KeyDeletionFailedException
+        }
+
+        keyFile.writeBytes(key.getPrivateKey())
+
+        key
+      }
+    }
+
+  override suspend fun removeKey(key: GPGKeyPair): Result<GPGKeyPair, Throwable> =
+    withContext(dispatcher) {
+      runCatching {
+        if (!keyDirExists()) throw KeyManagerException.KeyDirectoryUnavailableException
+        val keyFile = File(keyDir, "${key.getKeyId()}.$KEY_EXTENSION")
+        if (keyFile.exists()) {
+          if (!keyFile.delete()) throw KeyManagerException.KeyDeletionFailedException
+        }
+
+        key
+      }
+    }
+
+  override suspend fun getKeyById(id: String): Result<GPGKeyPair, Throwable> =
+    withContext(dispatcher) {
+      runCatching {
+        if (!keyDirExists()) throw KeyManagerException.KeyDirectoryUnavailableException
+        val keys = keyDir.listFiles()
+        if (keys.isNullOrEmpty()) throw KeyManagerException.NoKeysAvailableException
+
+        for (keyFile in keys) {
+          val keyPair = GPGKeyPair(Crypto.newKeyFromArmored(keyFile.readText()))
+          if (keyPair.getKeyId() == id) return@runCatching keyPair
+        }
+
+        throw KeyManagerException.KeyNotFoundException(id)
+      }
+    }
+
+  override suspend fun getAllKeys(): Result<List<GPGKeyPair>, Throwable> =
+    withContext(dispatcher) {
+      runCatching {
+        if (!keyDirExists()) throw KeyManagerException.KeyDirectoryUnavailableException
+        val keys = keyDir.listFiles()
+        if (keys.isNullOrEmpty()) return@runCatching listOf()
+
+        keys.map { GPGKeyPair(Crypto.newKeyFromArmored(it.readText())) }.toList()
+      }
+    }
+
+  override fun canHandle(fileName: String): Boolean {
+    // TODO: This is a temp hack for now and in future it should check that the GPGKeyManager can
+    // decrypt the file
+    return fileName.endsWith(KEY_EXTENSION)
+  }
+
+  private fun keyDirExists(): Boolean {
+    return keyDir.exists() || keyDir.mkdirs()
+  }
+
+  internal companion object {
+
+    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
+    internal const val KEY_DIR_NAME: String = "keys"
+    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
+    internal const val KEY_EXTENSION: String = "key"
+  }
+}
diff --git a/crypto-pgp/src/main/kotlin/dev/msfjarvis/aps/data/crypto/GPGKeyPair.kt b/crypto-pgp/src/main/kotlin/dev/msfjarvis/aps/data/crypto/GPGKeyPair.kt
new file mode 100644
index 00000000..2dbe8689
--- /dev/null
+++ b/crypto-pgp/src/main/kotlin/dev/msfjarvis/aps/data/crypto/GPGKeyPair.kt
@@ -0,0 +1,28 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package dev.msfjarvis.aps.data.crypto
+
+import com.proton.Gopenpgp.crypto.Key
+
+/** Wraps a Gopenpgp [Key] to implement [KeyPair]. */
+public class GPGKeyPair(private val key: Key) : KeyPair {
+
+  init {
+    if (!key.isPrivate) throw KeyPairException.PrivateKeyUnavailableException
+  }
+
+  override fun getPrivateKey(): ByteArray {
+    return key.armor().encodeToByteArray()
+  }
+
+  override fun getPublicKey(): ByteArray {
+    return key.armoredPublicKey.encodeToByteArray()
+  }
+
+  override fun getKeyId(): String {
+    return key.hexKeyID
+  }
+}
diff --git a/scripts/boot-emulator.sh b/scripts/boot-emulator.sh
new file mode 100755
index 00000000..abd73efa
--- /dev/null
+++ b/scripts/boot-emulator.sh
@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+
+# Boots an emulator that exactly matches the one in our CI. It is recommended
+# to use this as the target device for android tests.
+
+set -euo pipefail
+
+[ -n "${ANDROID_SDK_ROOT:-}" ] || {
+  echo "ANDROID_SDK_ROOT must be set to use this script"
+  exit
+  1
+}
+[ -n "${ANDROID_API_LEVEL:-}" ] || { echo "ANDROID_API_LEVEL not defined; defaulting to 30"; }
+
+API_LEVEL="${ANDROID_API_LEVEL:-30}"
+
+echo no | "${ANDROID_SDK_ROOT}"/cmdline-tools/latest/bin/avdmanager create avd \
+  --force \
+  -n "Pixel_XL_API_${API_LEVEL}" \
+  --abi 'google_apis/x86' \
+  --package "system-images;android-${API_LEVEL};google_apis;x86" \
+  --device 'pixel_xl'
+
+"${ANDROID_SDK_ROOT}"/emulator/emulator \
+  -avd "Pixel_XL_API_${API_LEVEL}" \
+  -no-window \
+  -gpu swiftshader_indirect \
+  -noaudio \
+  -no-boot-anim
diff --git a/scripts/setup-environment.sh b/scripts/setup-environment.sh
new file mode 100755
index 00000000..30dd0c19
--- /dev/null
+++ b/scripts/setup-environment.sh
@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+
+# Installs the latest command line tools and sets up the necessary packages for an Android emulator
+# for API level $ANDROID_API_LEVEL, or API 30 if unspecified.
+
+set -euo pipefail
+
+CMDLINE_TOOLS_URL_MAC="https://dl.google.com/android/repository/commandlinetools-mac-7583922_latest.zip"
+CMDLINE_TOOLS_URL_LINUX="https://dl.google.com/android/repository/commandlinetools-linux-7583922_latest.zip"
+
+[ -n "${ANDROID_SDK_ROOT:-}" ] || {
+  echo "ANDROID_SDK_ROOT must be set to use this script"
+  exit
+  1
+}
+
+if [ "$(uname)" == "Linux" ]; then
+  wget "${CMDLINE_TOOLS_URL_LINUX}" -O /tmp/tools.zip -o /dev/null
+elif [ "$(uname)" == "Darwin" ]; then
+  wget "${CMDLINE_TOOLS_URL_MAC}" -O /tmp/tools.zip -o /dev/null
+else
+  echo "This script only works on Linux and Mac"
+  exit 1
+fi
+
+[ -n "${ANDROID_API_LEVEL:-}" ] || { echo "ANDROID_API_LEVEL not defined; defaulting to 30"; }
+
+API_LEVEL="${ANDROID_API_LEVEL:-30}"
+
+unzip -qo /tmp/tools.zip -d "${ANDROID_SDK_ROOT}/latest"
+mkdir -p "${ANDROID_SDK_ROOT}/cmdline-tools"
+if [ -d "${ANDROID_SDK_ROOT}/cmdline-tools" ]; then
+  rm -rf "${ANDROID_SDK_ROOT}/cmdline-tools"
+fi
+mkdir -p "${ANDROID_SDK_ROOT}/cmdline-tools"
+mv -v "${ANDROID_SDK_ROOT}/latest/cmdline-tools" "${ANDROID_SDK_ROOT}/cmdline-tools/latest"
+
+export PATH="${ANDROID_SDK_ROOT}/cmdline-tools/latest/bin:${PATH}"
+
+sdkmanager --install 'build-tools;30.0.3' platform-tools "platforms;android-${API_LEVEL}"
+sdkmanager --install emulator
+sdkmanager --install "system-images;android-${API_LEVEL};google_apis;x86"