bb.gui
Class TextFieldSecure

java.lang.Object
  extended by java.awt.Component
      extended by java.awt.Container
          extended by javax.swing.JComponent
              extended by javax.swing.text.JTextComponent
                  extended by javax.swing.JTextField
                      extended by javax.swing.JPasswordField
                          extended by bb.gui.TextFieldSecure
All Implemented Interfaces:
ImageObserver, MenuContainer, Serializable, Accessible, Scrollable, SwingConstants

public class TextFieldSecure
extends JPasswordField

Subclass of JPasswordField which fixes defects in its superclass to offer superior security.

For top security, it is critical that:

  1. the text entered in the text field (or even its length) never gets revealed. This class achieves this by setting the echo char to an ordinary whitespace char and the caret to a TextFieldSecure.CaretSecure instance.
  2. a char[] be used as the underlying text storage medium (as opposed to, say, a String) and that the char[] be zeroed out when use is over. This class uses the TextFieldSecure.DocumentSecure and TextFieldSecure.ContentSecure classes to achieve this.
  3. serialization never writes out the sensitive text, where it would be exposed to the world. This class uses the TextFieldSecure.ContentSecure classes to prevent this.

Like typical Java GUI code, this class is not multithread safe: it expects to only be called by EventQueue's dispatch thread. This threading limitation is checked in every public method.

Author:
Brent Boyer
See Also:
Serialized Form

Nested Class Summary
private static class TextFieldSecure.CaretSecure
          Subclass of DefaultCaret which is designed for high security.
private static class TextFieldSecure.ContentSecure
          Subclass of GapContent which is designed for high security.
private static class TextFieldSecure.DocumentSecure
          Subclass of DocumentLimitedLength which is designed for high security.
 
Nested classes/interfaces inherited from class javax.swing.JPasswordField
JPasswordField.AccessibleJPasswordField
 
Nested classes/interfaces inherited from class javax.swing.JTextField
JTextField.AccessibleJTextField
 
Nested classes/interfaces inherited from class javax.swing.text.JTextComponent
JTextComponent.AccessibleJTextComponent, JTextComponent.DropLocation, JTextComponent.KeyBinding
 
Nested classes/interfaces inherited from class javax.swing.JComponent
JComponent.AccessibleJComponent
 
Nested classes/interfaces inherited from class java.awt.Container
Container.AccessibleAWTContainer
 
Nested classes/interfaces inherited from class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
 
Field Summary
private static long serialVersionUID
           
 
Fields inherited from class javax.swing.JTextField
notifyAction
 
Fields inherited from class javax.swing.text.JTextComponent
DEFAULT_KEYMAP, FOCUS_ACCELERATOR_KEY
 
Fields inherited from class javax.swing.JComponent
accessibleContext, listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW
 
Fields inherited from class java.awt.Component
BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
 
Fields inherited from interface javax.swing.SwingConstants
BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST
 
Fields inherited from interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
 
Constructor Summary
TextFieldSecure(int numberCharsMax)
          Constructs a new TextFieldSecure instance.
 
Method Summary
 TextFieldSecure.DocumentSecure getDocumentSecure()
          Returns the Document used by this instance, which is always a TextFieldSecure.DocumentSecure instance.
 char[] getInput()
          Returns a char[] of the chars currently in this instance.
 int getNumberCharsMax()
          Returns the maximum number of chars that may be typed in this instance.
private  void readObject(ObjectInputStream ois)
          Customizes deserialization.
 void zeroOutInput()
          Calls getDocumentSecure.
 
Methods inherited from class javax.swing.JPasswordField
copy, cut, echoCharIsSet, getAccessibleContext, getEchoChar, getPassword, getText, getText, getUIClassID, paramString, setEchoChar, updateUI
 
Methods inherited from class javax.swing.JTextField
actionPropertyChanged, addActionListener, configurePropertiesFromAction, createActionPropertyChangeListener, createDefaultModel, fireActionPerformed, getAction, getActionListeners, getActions, getColumns, getColumnWidth, getHorizontalAlignment, getHorizontalVisibility, getPreferredSize, getScrollOffset, isValidateRoot, postActionEvent, removeActionListener, scrollRectToVisible, setAction, setActionCommand, setColumns, setDocument, setFont, setHorizontalAlignment, setScrollOffset
 
Methods inherited from class javax.swing.text.JTextComponent
addCaretListener, addInputMethodListener, addKeymap, fireCaretUpdate, getCaret, getCaretColor, getCaretListeners, getCaretPosition, getDisabledTextColor, getDocument, getDragEnabled, getDropLocation, getDropMode, getFocusAccelerator, getHighlighter, getInputMethodRequests, getKeymap, getKeymap, getMargin, getNavigationFilter, getPreferredScrollableViewportSize, getPrintable, getScrollableBlockIncrement, getScrollableTracksViewportHeight, getScrollableTracksViewportWidth, getScrollableUnitIncrement, getSelectedText, getSelectedTextColor, getSelectionColor, getSelectionEnd, getSelectionStart, getToolTipText, getUI, isEditable, loadKeymap, modelToView, moveCaretPosition, paste, print, print, print, processInputMethodEvent, read, removeCaretListener, removeKeymap, removeNotify, replaceSelection, select, selectAll, setCaret, setCaretColor, setCaretPosition, setComponentOrientation, setDisabledTextColor, setDragEnabled, setDropMode, setEditable, setFocusAccelerator, setHighlighter, setKeymap, setMargin, setNavigationFilter, setSelectedTextColor, setSelectionColor, setSelectionEnd, setSelectionStart, setText, setUI, viewToModel, write
 
Methods inherited from class javax.swing.JComponent
addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingTile, isRequestFocusEnabled, paint, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setEnabled, setFocusTraversalKeys, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update
 
Methods inherited from class java.awt.Container
add, add, add, add, add, addContainerListener, addImpl, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusBackward, transferFocusDownCycle, validate, validateTree
 
Methods inherited from class java.awt.Component
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusUpCycle
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

serialVersionUID

private static final long serialVersionUID
See Also:
Constant Field Values
Constructor Detail

TextFieldSecure

public TextFieldSecure(int numberCharsMax)
                throws IllegalArgumentException,
                       IllegalStateException
Constructs a new TextFieldSecure instance.

Parameters:
numberCharsMax - the maximum number of chars that may be typed in this instance as well as its number of columns (this affects its displayed width); must be > 0
Throws:
IllegalArgumentException - if numberCharsMax <= 0
IllegalStateException - if calling thread is not EventQueue's dispatch thread
Method Detail

getDocumentSecure

public TextFieldSecure.DocumentSecure getDocumentSecure()
                                                 throws IllegalStateException
Returns the Document used by this instance, which is always a TextFieldSecure.DocumentSecure instance.

Throws:
IllegalStateException - if calling thread is not EventQueue's dispatch thread

getNumberCharsMax

public int getNumberCharsMax()
                      throws IllegalStateException
Returns the maximum number of chars that may be typed in this instance.

Throws:
IllegalStateException - if calling thread is not EventQueue's dispatch thread

getInput

public char[] getInput()
                throws IllegalStateException
Returns a char[] of the chars currently in this instance. Is just a renamed version of getPassword.

Throws:
IllegalStateException - if calling thread is not EventQueue's dispatch thread

zeroOutInput

public void zeroOutInput()
                  throws IllegalStateException
Calls getDocumentSecure.zeroOutContent().

Throws:
IllegalStateException - if calling thread is not EventQueue's dispatch thread

readObject

private void readObject(ObjectInputStream ois)
                 throws ClassNotFoundException,
                        IOException,
                        NotActiveException
Customizes deserialization. This method manually sets the caret field to a CaretSecure instance, since Sun wrongly declared that field transient. (If you look in the source code of JTextComponent, there is the comment "This should be serializable", so confirm in a later release of the JVM whether or not you need this method--may be able to eliminate.)

Throws:
ClassNotFoundException - if the class of a serialized object could not be found
IOException - if an I/O problem occurs
NotActiveException - if the stream is not currently reading objects