Android KeyStore Initialization

Question

First off I am new to android Programming, though I am not new to programming itself. What I am, essentially, trying to do is to save my encryption Keys into the Android Keystor

Answer 1

If you set your minSdkVersion to 23 or higher Android M makes it easy to generate and manage symmetric keys as of this month.

Check out the 4th example listed here. https://developer.android.com/reference/android/security/keystore/KeyGenParameterSpec.html

 KeyGenerator keyGenerator = KeyGenerator.getInstance(
         KeyProperties.KEY_ALGORITHM_AES, "AndroidKeyStore");
 keyGenerator.init(
         new KeyGenParameterSpec.Builder("key2",
                 KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT)
                 .setBlockModes(KeyProperties.BLOCK_MODE_GCM)
                 .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE)
                 .build());
 SecretKey key = keyGenerator.generateKey();

 Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 cipher.init(Cipher.ENCRYPT_MODE, key);
 ...

 // The key can also be obtained from the Android Keystore any time as follows:
 KeyStore keyStore = KeyStore.getInstance("AndroidKeyStore");
 keyStore.load(null);
 key = (SecretKey) keyStore.getKey("key2", null);

This example also was helpful. https://github.com/googlesamples/android-ConfirmCredential/blob/master/Application/src/main/java/com/example/android/confirmcredential/MainActivity.java