SecurePreferenceDataStore

Class Overview

A PreferenceDataStore implementation encrypts contents using 256-bit AES encryption, and is provided to the Preference framework via setPreferenceDataStore(PreferenceDataStore).

This class can be used to replace the default SharedPreferences and provides an extra layer of application data protection.

Creating and Opening

You must create and open the store with an encryption key before you can interact with it. It is recommended to use EncryptionUtil to obtain the encryption key. If this is the first time store is being opened and null is provided, an encryption key will be generated transparently and will be used for subsequent opens.

final String storeName = "myPreferenceStore";
    final byte[] encryptionKey = EncryptionUtil.getEncryptionKey("aliasForPreferenceStore",
        myPasscode);
    SecurePreferenceDataStore store = null;

    try {
        store = new SecurePreferenceDataStore(
                        androidContext, // Android application context.
                        storeName,      // Store name.
                        encryptionKey); // Store's encryption key; auto-generated if null.
    } catch (OpenFailureException ex) {
        logger.error("An error occurred while opening the preference data store.", ex);
    }
  

Adding and Retrieving Preferences

The following preference value types are supported:

• String
• Integer
• Long
• Float
• Boolean
• Any Set implementation that is Serializable

You can use the appropriate put and get methods to add and retrieve preference values to/from the data store.

try {
        // Adds preferences to the store.
        store.putInt("integerKey1", 58);
        store.putString("StringKey1", "A String value");
        store.putFloat("floatKey1", 9.8F);
        store.putLong("longKey1", 9223372036854775000L);
        store.putBoolean("booleanKey1", true);

        // Adds a set of values as a preference to the store.
        // 'stringSet' is a HashSet<String> that contains values.
        store.putStringSet(stringSetKey, stringSet);

        // Retrieves existing values.
        int intValue = store.getInt("integerKey1", 0);
        String stringValue = store.getString("StringKey1", "default String if not found");
        float floatValue = store.getFloat("floatKey1", 0.2F);
        long longValue = store.getLong("longKey1", 9223372036854775023L);
        boolean booleanValue = store.getBoolean("booleanKey1", false);
    } catch (BackingStoreException ex) {
        logger.error("Failed to add/retrieve preference.", ex);
    }
  

Removing Preferences

You can remove preferences one at a time or remove all at once.

try {
        // Removes preferences one at a time.
        store.remove("booleanKey1");
        store.remove("longKey1");

        // Removes all existing preferences.
        store.removeAll();
    } catch (BackingStoreException ex) {
        logger.error("Failed to remove preference.", ex);
    }
  

Changing Encryption Key

You can change the encryption of the underlying persistence store when the store is in open state.

store.changeEncryptionKey(newEncryptionKey);

 

Closing

When you finish CRUD operations on the store, close() the SecurePreferenceDataStore to relinquishes any resources it has acquired during its operations.

store.close();
  

Removing the persistence store

You may want to remove the persistence store in some occasions. Note that after the persistence store is removed, any further operation performed on the instance will cause FileMissingException.

store.deleteStore(context); // The store instance will not be usable after this method!

 

Summary

Public Constructors
	SecurePreferenceDataStore(Context context, String storeName, byte[] encryptionKey) Constructs a secure PreferenceDataStore.

Public Methods
void	changeEncryptionKey(byte[] newEncryptionKey) Changes the encryption key of the store while the store is opened (close() is not yet called).
void	close() Closes the store and relinquishes all resources acquired during its operations .
void	deleteStore(Context context) Deletes the underlying persistence store file.
boolean	getBoolean(String key, boolean defValue) Retrieves a boolean value from the data store.
float	getFloat(String key, float defValue) Retrieves a float value from the data store.
int	getInt(String key, int defValue) Retrieves an integer value from the data store.
long	getLong(String key, long defValue) Retrieves a long value from the data store.
String	getString(String key, String defValue) Retrieves a String value from the data store.
Set<String>	getStringSet(String key, Set<String> defValues) Retrieves a set of Strings from the data store.
void	putBoolean(String key, boolean value) Sets a boolean value to data store.
void	putFloat(String key, float value) Sets a float value to data store.
void	putInt(String key, int value) Sets an integer value to data store.
void	putLong(String key, long value) Sets a long value to data store.
void	putString(String key, String value) Sets a String value to data store.
void	putStringSet(String key, Set<String> values) Sets a set of Strings to the data store.
void	remove(String key) Removes a preference from the data store.
void	removeAll() Removes all preferences from the data store.

[Expand] Inherited Methods
From class androidx.preference.PreferenceDataStore boolean getBoolean(String arg0, boolean arg1) float getFloat(String arg0, float arg1) int getInt(String arg0, int arg1) long getLong(String arg0, long arg1) String getString(String arg0, String arg1) Set<String> getStringSet(String arg0, Set<String> arg1) void putBoolean(String arg0, boolean arg1) void putFloat(String arg0, float arg1) void putInt(String arg0, int arg1) void putLong(String arg0, long arg1) void putString(String arg0, String arg1) void putStringSet(String arg0, Set<String> arg1)
From class java.lang.Object Object clone() boolean equals(Object arg0) void finalize() final Class<?> getClass() int hashCode() final void notify() final void notifyAll() String toString() final void wait(long arg0, int arg1) final void wait(long arg0) final void wait()