dinorahto

val spec = KeyGenParameterSpec.Builder(
       KEY_NAME,
       KeyProperties.PURPOSE_ENCRYPT or
       KeyProperties.PURPOSE_DECRYPT
   ).apply {
       setBlockModes(KeyProperties.BLOCK_MODE_CBC)
       setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_PKCS7)
       setUserAuthenticationRequired(true)
       setUserAuthenticationValidityDurationSeconds(TIMEOUT_SECONDS)
       setRandomizedEncryptionRequired(false)

dinorahto

biometricPrompt.authenticate(promptInfo)

dinorahto

var biometricPrompt = BiometricPrompt(this, executor, object : BiometricPrompt.AuthenticationCallback() {
  override fun onAuthenticationError(errorCode: Int, errString: CharSequence) {
      super.onAuthenticationError(errorCode, errString)
      // Error 
  }

  override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
      super.onAuthenticationSucceeded(result)
      // Success
  }

dinorahto

val biometricPromptBuilder = BiometricPrompt.PromptInfo.Builder()
            .setTitle("A nice title")
            .setSubtitle("A nicer subtitle")
            .setNegativeButtonText("Cancel")
            .build()

dinorahto

//Write to file
encryptedFile.openFileOutput().bufferedWriter().use {
    it.write("Hola Mexico! vamos a encriptar esto")
}

//Read from file
val contents = encryptedFile.bufferedReader().useLines { lines ->
    lines.fold("") { working, line ->
        "$working\n$line"
    }

dinorahto

sharedPreferences.edit(commit = true) { 
    putString("Some key", "Some value")
}

dinorahto

val encryptedFile = EncryptedFile.Builder(
    File(directoryPath, "FileName"),
    context,
    masterKeyAlias,
    EncryptedFile.FileEncryptionScheme.AES256_GCM_HKDF_4KB
).build()

dinorahto

// Release Candidate Option
val sharedPreferences = EncryptedSharedPreferences.create(
    "FileName",
    masterKeyAlias,
    context,
    EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
    EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM
)

// Alpha Option

dinorahto

KeyPairGenerator.getInstance(KeyProperties.KEY_ALGORITHM_RSA, "AndroidKeyStore").apply {
    val certBuilder = KeyGenParameterSpec.Builder(alias, KeyProperties.PURPOSE_ENCRYPT)
        .setKeyValidityStart(keyValidityStart)
        .setKeyValidityEnd(keyValidityEnd)
        .setCertificateSerialNumber(BigInteger.valueOf(1L))
        .setCertificateSubject(X500Principal("CN=MyCompany"))
        .setUserAuthenticationRequired(true)
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
        initialize(
            certBuilder

dinorahto

// Release Candidate option
val keyGenParameterSpec = MasterKeys.AES256_GCM_SPEC
val masterKeyAlias = MasterKeys.getOrCreate(keyGenParameterSpec)

// Alpha option
val masterKeyAvailable = MasterKey
            .Builder(application.applicationContext)
            .setKeyScheme(MasterKey.KeyScheme.AES256_GCM)
            .build()