at.favre.lib.armadillo

Class SecureSharedPreferences

java.lang.Object

at.favre.lib.armadillo.SecureSharedPreferences

All Implemented Interfaces:

android.content.SharedPreferences, ArmadilloSharedPreferences

public final class SecureSharedPreferences
extends java.lang.Object
implements ArmadilloSharedPreferences

A simple wrapper implementation using the DefaultEncryptionProtocol before persisting the data. It deviates from the expected behaviour in the following way:

• The storage adds a meta entry containing a storage scoped salt value
• getAll() will return the hashed keys and an empty string as content
• getAll() will NOT include the storage salt (i.e size of the returned map only reflects the user added values)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	SecureSharedPreferences.Editor Wrapper for Android's SharedPreferences.Editor.

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

android.content.SharedPreferences.OnSharedPreferenceChangeListener

Constructor Summary

Constructors

Constructor and Description
SecureSharedPreferences(android.content.Context context, java.lang.String preferenceName, at.favre.lib.armadillo.EncryptionProtocol.Factory encryptionProtocol, char[] password, boolean supportVerifyPassword)
SecureSharedPreferences(android.content.Context context, java.lang.String preferenceName, at.favre.lib.armadillo.EncryptionProtocol.Factory encryptionProtocol, RecoveryPolicy recoveryPolicy, char[] password, boolean supportVerifyPassword)
SecureSharedPreferences(android.content.SharedPreferences sharedPreferences, at.favre.lib.armadillo.EncryptionProtocol.Factory encryptionProtocolFactory, RecoveryPolicy recoveryPolicy, char[] password, boolean supportVerifyPassword)

Method Summary

Modifier and Type	Method and Description
void	changePassword(char[] newPassword) Changes the user provided password to the new given password.
void	changePassword(char[] newPassword, KeyStretchingFunction newKsFunction) Changes the user provided password to the new given password and sets a new stretching function.
void	close() Clears most of the internal state and makes the instance unusable.
boolean	contains(java.lang.String key)
android.content.SharedPreferences.Editor	edit()
java.util.Map<java.lang.String,java.lang.String>	getAll() This will get all handled keys from the store.
boolean	getBoolean(java.lang.String key, boolean defaultValue)
float	getFloat(java.lang.String key, float defaultValue)
int	getInt(java.lang.String key, int defaultValue)
long	getLong(java.lang.String key, long defaultValue)
java.lang.String	getString(java.lang.String key, java.lang.String defaultValue)
java.util.Set<java.lang.String>	getStringSet(java.lang.String key, java.util.Set<java.lang.String> defaultValues)
boolean	isValidPassword() Determines whether the user-provided password used to initialises Armadillo is the right one or not.
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

Constructor Detail

SecureSharedPreferences

public SecureSharedPreferences(android.content.Context context,
                               java.lang.String preferenceName,
                               at.favre.lib.armadillo.EncryptionProtocol.Factory encryptionProtocol,
                               char[] password,
                               boolean supportVerifyPassword)

SecureSharedPreferences

public SecureSharedPreferences(android.content.Context context,
                               java.lang.String preferenceName,
                               at.favre.lib.armadillo.EncryptionProtocol.Factory encryptionProtocol,
                               RecoveryPolicy recoveryPolicy,
                               char[] password,
                               boolean supportVerifyPassword)

SecureSharedPreferences

public SecureSharedPreferences(android.content.SharedPreferences sharedPreferences,
                               at.favre.lib.armadillo.EncryptionProtocol.Factory encryptionProtocolFactory,
                               RecoveryPolicy recoveryPolicy,
                               char[] password,
                               boolean supportVerifyPassword)

Method Detail

getAll

public java.util.Map<java.lang.String,java.lang.String> getAll()

This will get all handled keys from the store. It will NOT decrypt any content.

Specified by:

getAll in interface android.content.SharedPreferences

Returns:

map with only the keys and null as value

getString

public java.lang.String getString(java.lang.String key,
                                  java.lang.String defaultValue)

Specified by:

getString in interface android.content.SharedPreferences

getStringSet

public java.util.Set<java.lang.String> getStringSet(java.lang.String key,
                                                    java.util.Set<java.lang.String> defaultValues)

Specified by:

getStringSet in interface android.content.SharedPreferences

getInt

public int getInt(java.lang.String key,
                  int defaultValue)

Specified by:

getInt in interface android.content.SharedPreferences

getLong

public long getLong(java.lang.String key,
                    long defaultValue)

Specified by:

getLong in interface android.content.SharedPreferences

getFloat

public float getFloat(java.lang.String key,
                      float defaultValue)

Specified by:

getFloat in interface android.content.SharedPreferences

getBoolean

public boolean getBoolean(java.lang.String key,
                          boolean defaultValue)

Specified by:

getBoolean in interface android.content.SharedPreferences

contains

public boolean contains(java.lang.String key)

Specified by:

contains in interface android.content.SharedPreferences

edit

public android.content.SharedPreferences.Editor edit()

Specified by:

edit 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

changePassword

public void changePassword(char[] newPassword)

Description copied from interface: ArmadilloSharedPreferences

Changes the user provided password to the new given password. This will immediately reencrypt all the key/value entries with the new password and the data won't be accessible with the old one anymore. This process is atomic, if an exception happens during it, nothing will change.

This method can be used to switch from a generated key to a key derived from user-provided password.

A null or zero length password will reset the password (as if no user-provided password is set).

Warning: Depending on the use key stretching function and count of saved data this is a very expensive call, do it in a background thread.

Specified by:

changePassword in interface ArmadilloSharedPreferences

Parameters:

newPassword - which will be additionally used to create the key for the encryption

isValidPassword

public boolean isValidPassword()

Description copied from interface: ArmadilloSharedPreferences

Determines whether the user-provided password used to initialises Armadillo is the right one or not.

Armadillo.Builder.supportVerifyPassword(boolean) has to be enabled to be able to use this method.

In order to verify the password, a known value is stored encrypted with the password the first time that Armadillo is initialised. When this method is called, it tries to decrypt this value and compares it to the original value. If the values match the validation succeeds, otherwise, it fails.

Warning: Depending on the use key stretching function this is a very expensive call, do it in a background thread.

Specified by:

isValidPassword in interface ArmadilloSharedPreferences

Returns:

true is the password is valid, false otherwise

changePassword

public void changePassword(char[] newPassword,
                           KeyStretchingFunction newKsFunction)

Description copied from interface: ArmadilloSharedPreferences

Changes the user provided password to the new given password and sets a new stretching function. This will immediately reencrypt all the key/value entries with the new password and the data won't be accessible with the old one anymore. This process is atomic, if an exception happens during it, nothing will change.

This method can be used to switch from a generated key to a key derived from user-provided password.

A null or zero length password will reset the password (as if no user-provided password is set).

Warning: Depending on the use key stretching function and count of saved data this is a very expensive call, do it in a background thread.

Specified by:

changePassword in interface ArmadilloSharedPreferences

Parameters:

newPassword - which will be additionally used to create the key for the encryption

newKsFunction - set a new function to be used the encrypt with new password. It will be ignored if null is passed.

close

public void close()

Description copied from interface: ArmadilloSharedPreferences

Clears most of the internal state and makes the instance unusable. User-provided password is cleared.

Specified by:

close in interface ArmadilloSharedPreferences