oak.app

Class CryptoSharedPreferences

java.lang.Object

oak.app.CryptoSharedPreferences

All Implemented Interfaces:

android.content.SharedPreferences

Direct Known Subclasses:

EncryptedPreferences, EncryptedSharedPreferences

public abstract class CryptoSharedPreferences
extends Object
implements android.content.SharedPreferences

This code originally posted by Michael Burton on StackOverflow http://stackoverflow.com/questions/785973/what-is-the-most-appropriate-way-to-store-user-settings-in-android-application/6393502#6393502

This class was created to replace the original ObscurredSharedPreferences. It includes DES and AES encryption options, and uses a randomly generate initialization vector to ensure each encrypted string is unique. If no crypto type is specified the default is AES.

Note: There was a flaw in the JCA in some versions of Android. There is a fix, see this: http://android-developers.blogspot.com/2013/08/some-securerandom-thoughts.html

The code provided is also provided in OAK. You should call PRNGFixes.apply() in your Application.onCreate() method if you are using this library to ensure strong keys are created.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	CryptoSharedPreferences.Editor

Nested classes/interfaces inherited from interface android.content.SharedPreferences

android.content.SharedPreferences.OnSharedPreferenceChangeListener

Field Summary

Fields

Modifier and Type	Field and Description
protected static String	CIPHER_ALGORITHM_AES
protected static String	CIPHER_ALGORITHM_DES
protected android.content.Context	context
static int	CRYPTO_AES
static int	CRYPTO_DES
protected android.content.SharedPreferences	delegate
protected static int	IV_LENGTH
protected static String	PBE_ALGORITHM_AES
protected static String	PBE_ALGORITHM_DES
protected static String	RANDOM_ALGORITHM
protected static int	SECRET_KEY_ITERATIONS
protected static String	UTF8

Constructor Summary

Constructors

Constructor and Description
CryptoSharedPreferences(android.content.Context context, android.content.SharedPreferences delegate)

Method Summary

Modifier and Type	Method and Description
boolean	contains(String s)
protected String	decrypt_AES(String value)
protected String	decrypt_DES(String value)
protected String	decrypt(String value)
CryptoSharedPreferences.Editor	edit()
protected String	encrypt_AES(String value)
protected String	encrypt_DES(String value)
protected String	encrypt(String value)
Map<String,?>	getAll()
boolean	getBoolean(String key, boolean defValue)
float	getFloat(String key, float defValue)
int	getInt(String key, int defValue)
long	getLong(String key, long defValue)
protected abstract char[]	getSpecialCode() Implement this method to supply your char array with your password.
String	getString(String key, String defValue)
void	registerOnSharedPreferenceChangeListener(android.content.SharedPreferences.OnSharedPreferenceChangeListener onSharedPreferenceChangeListener)
void	unregisterOnSharedPreferenceChangeListener(android.content.SharedPreferences.OnSharedPreferenceChangeListener onSharedPreferenceChangeListener)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface android.content.SharedPreferences

getStringSet

Field Detail

UTF8

protected static final String UTF8

See Also:

Constant Field Values

SECRET_KEY_ITERATIONS

protected static final int SECRET_KEY_ITERATIONS

See Also:

Constant Field Values

IV_LENGTH

protected static final int IV_LENGTH

See Also:

Constant Field Values

RANDOM_ALGORITHM

protected static final String RANDOM_ALGORITHM

See Also:

Constant Field Values

CIPHER_ALGORITHM_AES

protected static final String CIPHER_ALGORITHM_AES

See Also:

Constant Field Values

PBE_ALGORITHM_AES

protected static final String PBE_ALGORITHM_AES

See Also:

Constant Field Values

CIPHER_ALGORITHM_DES

protected static final String CIPHER_ALGORITHM_DES

See Also:

Constant Field Values

PBE_ALGORITHM_DES

protected static final String PBE_ALGORITHM_DES

See Also:

Constant Field Values

delegate

protected android.content.SharedPreferences delegate

context

protected android.content.Context context

CRYPTO_AES

public static final int CRYPTO_AES

See Also:

Constant Field Values

CRYPTO_DES

public static final int CRYPTO_DES

See Also:

Constant Field Values

Constructor Detail

CryptoSharedPreferences

public CryptoSharedPreferences(android.content.Context context,
                               android.content.SharedPreferences delegate)

Method Detail

getSpecialCode

protected abstract char[] getSpecialCode()

Implement this method to supply your char array with your password. Ideally this is from user input or an external api and not a hard-coded string.

Returns:

edit

public CryptoSharedPreferences.Editor edit()

Specified by:

edit in interface android.content.SharedPreferences

getAll

public Map<String,?> getAll()

Specified by:

getAll in interface android.content.SharedPreferences

getBoolean

public boolean getBoolean(String key,
                          boolean defValue)

Specified by:

getBoolean in interface android.content.SharedPreferences

getFloat

public float getFloat(String key,
                      float defValue)

Specified by:

getFloat in interface android.content.SharedPreferences

getInt

public int getInt(String key,
                  int defValue)

Specified by:

getInt in interface android.content.SharedPreferences

getLong

public long getLong(String key,
                    long defValue)

Specified by:

getLong in interface android.content.SharedPreferences

getString

public String getString(String key,
                        String defValue)

Specified by:

getString in interface android.content.SharedPreferences

contains

public boolean contains(String s)

Specified by:

contains in interface android.content.SharedPreferences

registerOnSharedPreferenceChangeListener

public void registerOnSharedPreferenceChangeListener(android.content.SharedPreferences.OnSharedPreferenceChangeListener onSharedPreferenceChangeListener)

Specified by:

registerOnSharedPreferenceChangeListener in interface android.content.SharedPreferences

unregisterOnSharedPreferenceChangeListener

public void unregisterOnSharedPreferenceChangeListener(android.content.SharedPreferences.OnSharedPreferenceChangeListener onSharedPreferenceChangeListener)

Specified by:

unregisterOnSharedPreferenceChangeListener in interface android.content.SharedPreferences

encrypt

protected String encrypt(String value)

decrypt

protected String decrypt(String value)

encrypt_AES

protected String encrypt_AES(String value)

decrypt_AES

protected String decrypt_AES(String value)

encrypt_DES

protected String encrypt_DES(String value)

decrypt_DES

protected String decrypt_DES(String value)