library

This library contains the following:

• [ObscuredSharedPreferences] (src/main/java/in/co/ophio/secure/core/ObscuredSharedPreferences.java): An implementation of SharedPreferences that can store keys and values in obscured manner.
• [ObscuredPreferencesBuilder] (src/main/java/in/co/ophio/secure/core/ObscuredPreferencesBuilder.java): Can be used to obtain an instance of ObscuredSharedPreferences.
• [KeyStoreKeyGenerator] (src/main/java/in/co/ophio/secure/core/KeyStoreKeyGenerator.java): used to generate keys using Android Keystore System

[ObscuredSharedPreferences] (src/main/java/in/co/ophio/secure/core/ObscuredSharedPreferences.java)

• Main idea by Mike Burton in an answer posted here.
• It is mandatory to set key using setSecret() method otherwise IllegalAccessException will be thrown.
• Uses PBEWithMD5AndDES to encode the keys and/or values.
• Overrides methods like putBoolean(), putFloat(), getBoolean(), getFloat(), contains(), getAll(), ... to provide an obscured implementation.

[ObscuredPreferencesBuilder] (library/src/main/java/in/co/ophio/secure/core/ObscuredPreferencesBuilder.java)

• Will return an instance of ObscuredPreferencesBuilder if atleast one of the obfuscateKey() OR obfuscateValue() is set.
• If none of the above methods are set it will return simple SharedPreferences implementation.
• Example:

SharedPreferences sharedPreferences = new ObscuredPreferencesBuilder()
                .setApplication(KeystoreApplication.getAppContext())
                .obfuscateValue(true)
                .obfuscateKey(true)
                .setSharePrefFileName(PREFS_NAME)
                .setSecret("some key")		
                .createSharedPrefs();

[KeyStoreKeyGenerator] (src/main/java/in/co/ophio/secure/core/KeyStoreKeyGenerator.java)

• method loadOrGenerateKeys(): Subsequent calls of same method in an application returns the same key. Uses Android Keystore System to generate and return key. It throws IllegalStateException if some error occurred while trying to generate keys.
• method isHardwareBacked(): Flag indicating that the SecretKeyWrapper public/private key is hardware-backed. A software keystore is more vulnerable to offline attacks if the device is compromised.
• Example:

	String key = KeyGenerator.get(KeystoreApplication.getAppContext(),
					KeystoreApplication.getAppContext().getPackageName())
						.loadOrGenerateKeys();