Package org.elasticsearch.common.settings

Class SecureString

java.lang.Object

org.elasticsearch.common.settings.SecureString

All Implemented Interfaces:

Closeable, AutoCloseable, CharSequence

public final class SecureString
extends Object
implements CharSequence, Closeable

A String implementations which allows clearing the underlying char array.

Constructor Summary

Constructors

Constructor	Description
SecureString(char[] chars)	Constructs a new SecureString which controls the passed in char array.
SecureString(String s)	Deprecated. Only use for compatibility between deprecated string settings and new secure strings

Method Summary

Modifier and Type	Method	Description
char	charAt(int index)
SecureString	clone()	Returns a new copy of this object that is backed by its own char array.
void	close()	Closes the string by clearing the underlying char array.
boolean	equals(Object o)	Constant time equality to avoid potential timing attacks.
char[]	getChars()	Returns the underlying char[].
int	hashCode()
int	length()
SecureString	subSequence(int start, int end)
String	toString()	Convert to a String.

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.CharSequence

chars, codePoints

Constructor Detail

SecureString

public SecureString(char[] chars)

Constructs a new SecureString which controls the passed in char array. Note: When this instance is closed, the array will be zeroed out.

SecureString

@Deprecated
public SecureString(String s)

Deprecated.

Only use for compatibility between deprecated string settings and new secure strings

Constructs a new SecureString from an existing String. NOTE: This is not actually secure, since the provided String cannot be deallocated, but this constructor allows for easy compatibility between new and old apis.

Method Detail

equals

public boolean equals(Object o)

Constant time equality to avoid potential timing attacks.

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

length

public int length()

Specified by:

length in interface CharSequence

charAt

public char charAt(int index)

Specified by:

charAt in interface CharSequence

subSequence

public SecureString subSequence(int start,
                                int end)

Specified by:

subSequence in interface CharSequence

toString

public String toString()

Convert to a String. This should only be used with APIs that do not take CharSequence.

Specified by:

toString in interface CharSequence

Overrides:

toString in class Object

close

public void close()

Closes the string by clearing the underlying char array.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

clone

public SecureString clone()

Returns a new copy of this object that is backed by its own char array. Closing the new instance has no effect on the instance it was created from. This is useful for APIs which accept a char array and you want to be safe about the API potentially modifying the char array. For example:

     try (SecureString copy = secureString.clone()) {
         // pass thee char[] to a external API
         PasswordAuthentication auth = new PasswordAuthentication(username, copy.getChars());
         ...
     }
 

Overrides:

clone in class Object

getChars

public char[] getChars()

Returns the underlying char[]. This is a dangerous operation as the array may be modified while it is being used by other threads or a consumer may modify the values in the array. For safety, it is preferable to use clone() and pass its chars to the consumer when the chars are needed multiple times.