javax.crypto.spec

Class SecretKeySpec

java.lang.Object

javax.crypto.spec.SecretKeySpec

All Implemented Interfaces:

Serializable, Key, KeySpec, SecretKey, Destroyable

public class SecretKeySpec
extends Object
implements KeySpec, SecretKey

This class specifies a secret key in a provider-independent fashion.

It can be used to construct a SecretKey from a byte array, without having to go through a (provider-based) SecretKeyFactory.

This class is only useful for raw secret keys that can be represented as a byte array and have no key parameters associated with them, e.g., DES or Triple DES keys.

Since:

1.4

Author:

Jan Luehe

See Also:

SecretKey, Serialized Form

Constructor Summary

Constructors

Constructor and Description
SecretKeySpec(byte[] key, int offset, int len, String algorithm) Constructs a secret key from the given byte array, using the first len bytes of key, starting at offset inclusive.
SecretKeySpec(byte[] key, String algorithm) Constructs a secret key from the given byte array.

Method Summary

Modifier and Type	Method and Description
void	destroy() Destroy this Object.
boolean	equals(Object obj) Tests for equality between the specified object and this object.
String	getAlgorithm() Returns the name of the algorithm associated with this secret key.
byte[]	getEncoded() Returns the key material of this secret key.
String	getFormat() Returns the name of the encoding format for this secret key.
int	hashCode() Calculates a hash code value for the object.
boolean	isDestroyed() Determine if this Object has been destroyed.

Methods inherited from class java.lang.Object

clone, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SecretKeySpec

public SecretKeySpec(byte[] key,
                     int offset,
                     int len,
                     String algorithm)

Constructs a secret key from the given byte array, using the first len bytes of key, starting at offset inclusive.

The bytes that constitute the secret key are those between key[offset] and key[offset+len-1] inclusive.

This constructor does not check if the given bytes indeed specify a secret key of the specified algorithm. For example, if the algorithm is DES, this constructor does not check if key is 8 bytes long, and also does not check for weak or semi-weak keys. In order for those checks to be performed, an algorithm-specific key specification class must be used.

Parameters:

key - the key material of the secret key. The first len bytes of the array beginning at offset inclusive are copied to protect against subsequent modification.

offset - the offset in key where the key material starts.

len - the length of the key material.

algorithm - the name of the secret-key algorithm to be associated with the given key material. See Appendix A in the Java Cryptography Architecture Reference Guide for information about standard algorithm names.

Throws:

IllegalArgumentException - if algorithm is null or key is null, empty, or too short, i.e. key.length-offset<len.

ArrayIndexOutOfBoundsException - is thrown if offset or len index bytes outside the key.

SecretKeySpec

public SecretKeySpec(byte[] key,
                     String algorithm)

Constructs a secret key from the given byte array.

This constructor does not check if the given bytes indeed specify a secret key of the specified algorithm. For example, if the algorithm is DES, this constructor does not check if key is 8 bytes long, and also does not check for weak or semi-weak keys. In order for those checks to be performed, an algorithm-specific key specification class should be used.

Parameters:

key - the key material of the secret key. The contents of the array are copied to protect against subsequent modification.

algorithm - the name of the secret-key algorithm to be associated with the given key material. See Appendix A in the Java Cryptography Architecture Reference Guide for information about standard algorithm names.

Throws:

IllegalArgumentException - if algorithm is null or key is null or empty.

Method Detail

destroy

public void destroy()
             throws DestroyFailedException

Description copied from interface: Destroyable

Destroy this Object.

Sensitive information associated with this Object is destroyed or cleared. Subsequent calls to certain methods on this Object will result in an IllegalStateException being thrown.

The default implementation throws DestroyFailedException.

Specified by:

destroy in interface Destroyable

Throws:

DestroyFailedException - if the destroy operation fails.

equals

public boolean equals(@Nullable
                      Object obj)

Tests for equality between the specified object and this object. Two SecretKeySpec objects are considered equal if they are both SecretKey instances which have the same case-insensitive algorithm name and key encoding.

Overrides:

equals in class Object

Parameters:

obj - the object to test for equality with this object.

Returns:

true if the objects are considered equal, false if obj is null or otherwise.

See Also:

Object.hashCode(), HashMap

getAlgorithm

public String getAlgorithm()

Returns the name of the algorithm associated with this secret key.

Returns:

the secret key algorithm.

getEncoded

public byte[] getEncoded()

Returns the key material of this secret key.

Returns:

the key material. Returns a new array each time this method is called.

getFormat

public String getFormat()

Returns the name of the encoding format for this secret key.

Returns:

the string "RAW".

hashCode

public int hashCode()

Calculates a hash code value for the object. Objects that are equal will also have the same hashcode.

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

isDestroyed

public boolean isDestroyed()

Description copied from interface: Destroyable

Determine if this Object has been destroyed.

The default implementation returns false.

Specified by:

isDestroyed in interface Destroyable

Returns:

true if this Object has been destroyed, false otherwise.