javax.crypto.spec

Class DESKeySpec

java.lang.Object

javax.crypto.spec.DESKeySpec

All Implemented Interfaces:

java.security.spec.KeySpec

public class DESKeySpec
extends java.lang.Object
implements java.security.spec.KeySpec

This class specifies a DES key.

Since:

1.4

Version:

1.21, 01/07/04

Author:

Jan Luehe

Field Summary

Fields

Modifier and Type	Field and Description
static int	DES_KEY_LEN The constant which defines the length of a DES key in bytes.

Constructor Summary

Constructors

Constructor and Description
DESKeySpec(byte[] key) Creates a DESKeySpec object using the first 8 bytes in key as the key material for the DES key.
DESKeySpec(byte[] key, int offset) Creates a DESKeySpec object using the first 8 bytes in key, beginning at offset inclusive, as the key material for the DES key.

Method Summary

Modifier and Type	Method and Description
byte[]	getKey() Returns the DES key material.
static boolean	isParityAdjusted(byte[] key, int offset) Checks if the given DES key material, starting at offset inclusive, is parity-adjusted.
static boolean	isWeak(byte[] key, int offset) Checks if the given DES key material is weak or semi-weak.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DES_KEY_LEN

public static final int DES_KEY_LEN

The constant which defines the length of a DES key in bytes.

See Also:

Constant Field Values

Constructor Detail

DESKeySpec

public DESKeySpec(byte[] key)
           throws java.security.InvalidKeyException

Creates a DESKeySpec object using the first 8 bytes in key as the key material for the DES key.

The bytes that constitute the DES key are those between key[0] and key[7] inclusive.

Parameters:

key - the buffer with the DES key material. The first 8 bytes of the buffer are copied to protect against subsequent modification.

Throws:

java.lang.NullPointerException - if the given key material is null

java.security.InvalidKeyException - if the given key material is shorter than 8 bytes.

DESKeySpec

public DESKeySpec(byte[] key,
                  int offset)
           throws java.security.InvalidKeyException

Creates a DESKeySpec object using the first 8 bytes in key, beginning at offset inclusive, as the key material for the DES key.

The bytes that constitute the DES key are those between key[offset] and key[offset+7] inclusive.

Parameters:

key - the buffer with the DES key material. The first 8 bytes of the buffer beginning at offset inclusive are copied to protect against subsequent modification.

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

Throws:

java.lang.NullPointerException - if the given key material is null

java.security.InvalidKeyException - if the given key material, starting at offset inclusive, is shorter than 8 bytes.

Method Detail

getKey

public byte[] getKey()

Returns the DES key material.

Returns:

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

isParityAdjusted

public static boolean isParityAdjusted(byte[] key,
                                       int offset)
                                throws java.security.InvalidKeyException

Checks if the given DES key material, starting at offset inclusive, is parity-adjusted.

Parameters:

key - the buffer with the DES key material.

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

Returns:

true if the given DES key material is parity-adjusted, false otherwise.

Throws:

java.security.InvalidKeyException - if the given key material is null, or starting at offset inclusive, is shorter than 8 bytes.

isWeak

public static boolean isWeak(byte[] key,
                             int offset)
                      throws java.security.InvalidKeyException

Checks if the given DES key material is weak or semi-weak.

Parameters:

key - the buffer with the DES key material.

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

Returns:

true if the given DES key material is weak or semi-weak, false otherwise.

Throws:

java.security.InvalidKeyException - if the given key material is null, or starting at offset inclusive, is shorter than 8 bytes.