API java : DESKeySpec

javax.crypto.spec
Class DESKeySpec

java.lang.Object
  javax.crypto.spec.DESKeySpec

All Implemented Interfaces:

KeySpec

public class DESKeySpec
extends Object
implements KeySpec

This class specifies a DES key.

Since:

1.4

Field Summary
static int	DES_KEY_LEN           The constant which defines the length of a DES key in bytes.

 

Constructor Summary
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
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

DESKeySpec

public DESKeySpec(byte[] key)
           throws 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:

NullPointerException - if the given key material is null

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

DESKeySpec

public DESKeySpec(byte[] key,
                  int offset)
           throws 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:

NullPointerException - if the given key material is null

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

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 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:

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 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:

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