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org.mozilla.jss.util
Class Password

java.lang.Object
  org.mozilla.jss.util.Password

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, PasswordCallback

public class Password
extends java.lang.Object
implements PasswordCallback, java.lang.Cloneable, java.io.Serializable

Stores a password. clear should be called when the password is no longer needed so that the sensitive information is not left in memory.

A Password can be used as a hard-coded PasswordCallback.

See Also:

PasswordCallback, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.mozilla.jss.util.PasswordCallback

PasswordCallback.GiveUpException

Constructor Summary

Password(char[] pw)
Creates a Password from a char array, then wipes the char array.

Method Summary

static byte[]	charToByte(char[] charArray) Converts a char array to a null-terminated byte array using a standard encoding, which is currently UTF8.
void	clear() Clears the password so that sensitive data is no longer present in memory.
java.lang.Object	clone() Clones the password.
boolean	equals(java.lang.Object obj) Compares this password to another and returns true if they are the same.
protected void	finalize() The finalizer clears the sensitive information before releasing it to the garbage collector, but it should have been cleared manually before this point anyway.
char[]	getCharCopy() Returns a char array that is a copy of the password.
char[]	getChars() Returns the char array underlying this password.
Password	getPasswordAgain(PasswordCallbackInfo info) An implementation of PasswordCallback.getPasswordAgain.
Password	getPasswordFirstAttempt(PasswordCallbackInfo info) An implementation of PasswordCallback.getPasswordFirstAttempt.
static Password	readPasswordFromConsole() Reads a password from the console with echo disabled.
static void	wipeBytes(byte[] byteArray) Wipes a byte array by setting all its elements to zero.
static void	wipeChars(char[] charArray) Wipes a char array by setting all its elements to zero.

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Password

public Password(char[] pw)

Creates a Password from a char array, then wipes the char array.

Parameters:

pw - A char[] containing the password. This array will be cleared (set to zeroes) by the constructor.

Method Detail

getPasswordFirstAttempt

public Password getPasswordFirstAttempt(PasswordCallbackInfo info)
                                 throws PasswordCallback.GiveUpException

An implementation of PasswordCallback.getPasswordFirstAttempt. This allows a Password object to be treated as a PasswordCallback. This method simply returns a clone of the password.

Specified by:

getPasswordFirstAttempt in interface PasswordCallback

Parameters:

info - Information about the token that is being logged into.

Returns:

A copy of the password. The caller is responsible for clearing this copy.

Throws:

PasswordCallback.GiveUpException - If the callback does not want to supply a password.

equals

public boolean equals(java.lang.Object obj)

Compares this password to another and returns true if they are the same.

Overrides:

equals in class java.lang.Object

getPasswordAgain

public Password getPasswordAgain(PasswordCallbackInfo info)
                          throws PasswordCallback.GiveUpException

An implementation of PasswordCallback.getPasswordAgain. This allows a Password object to be used as a PasswordCallback. This method is only called after a call to getPasswordFirstAttempt returned the wrong password. This means the password is incorrect and there's no sense returning it again, so a GiveUpException is thrown.

Specified by:

getPasswordAgain in interface PasswordCallback

Parameters:

info - Information about the token that is being logged into.

Returns:

The password. This password object is owned by and will be cleared by the caller.

Throws:

PasswordCallback.GiveUpException - If the callback does not want to supply a password. This may often be the case if the first attempt failed.

getChars

public char[] getChars()

Returns the char array underlying this password. It must not be modified in any way.

getCharCopy

public char[] getCharCopy()

Returns a char array that is a copy of the password. The caller is responsible for wiping the returned array, for example using wipeChars.

clear

public void clear()

Clears the password so that sensitive data is no longer present in memory. This should be called as soon as the password is no longer needed.

clone

public java.lang.Object clone()

Clones the password. The resulting clone will be completely independent of the parent, which means it will have to be separately cleared.

Overrides:

clone in class java.lang.Object

finalize

protected void finalize()
                 throws java.lang.Throwable

The finalizer clears the sensitive information before releasing it to the garbage collector, but it should have been cleared manually before this point anyway.

Overrides:

finalize in class java.lang.Object

Throws:

java.lang.Throwable

charToByte

public static byte[] charToByte(char[] charArray)

Converts a char array to a null-terminated byte array using a standard encoding, which is currently UTF8. The caller is responsible for clearing the copy (with wipeBytes, for example).

Parameters:

charArray - A character array, which should not be null. It will be wiped with zeroes.

Returns:

A copy of the charArray, converted from Unicode to UTF8. It is the responsibility of the caller to clear the output byte array; wipeBytes is ideal for this purpose.

See Also:

wipeBytes(byte[])

wipeBytes

public static void wipeBytes(byte[] byteArray)

Wipes a byte array by setting all its elements to zero. null must not be passed in.

wipeChars

public static void wipeChars(char[] charArray)

Wipes a char array by setting all its elements to zero. null must not be passed in.

readPasswordFromConsole

public static Password readPasswordFromConsole()
                                        throws PasswordCallback.GiveUpException

Reads a password from the console with echo disabled. This is a blocking call which will return after the user types a newline. It only works with ASCII password characters. The call is synchronized because it alters terminal settings in a way that is not thread-safe.

Returns:

The password the user entered at the command line.

Throws:

PasswordCallback.GiveUpException - If the user enters no password (just hits <enter>).