IT. Expert System.

All Implemented Interfaces:

KeySpec

public class DESKeySpec
extends Object
implements KeySpec

• Field Summary

  Fields

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

• Constructor Summary

  Constructors

  Constructor and Description
  DESKeySpec(byte[] key) Creates a new DESKeySpec from the first 8 bytes of the specified key data.
  DESKeySpec(byte[] key, int offset) Creates a new DESKeySpec from the first 8 bytes of the specified key data starting at offset.

• Method Summary

  Methods

  Modifier and Type	Method and Description
  byte[]	getKey() Returns a copy of the key.
  static boolean	isParityAdjusted(byte[] key, int offset) Returns whether the specified key data starting at offset is parity-adjusted.
  static boolean	isWeak(byte[] key, int offset) Returns whether the specified key data starting at offset 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 length of a DES key in bytes.

    See Also:

    Constant Field Values

• Constructor Detail

  • DESKeySpec

    public DESKeySpec(byte[] key)
               throws InvalidKeyException

    Creates a new DESKeySpec from the first 8 bytes of the specified key data.

    Parameters:

    key - the key data.

    Throws:

    InvalidKeyException - if the length of the specified key data is less than 8.

  • DESKeySpec

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

    Creates a new DESKeySpec from the first 8 bytes of the specified key data starting at offset.

    Parameters:

    key - the key data

    offset - the offset to start at.

    Throws:

    InvalidKeyException - if the length of the specified key data starting at offset is less than 8.

• Method Detail

  • getKey

    public byte[] getKey()

    Returns a copy of the key.

    Returns:

    a copy of the key.

  • isParityAdjusted

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

    Returns whether the specified key data starting at offset is parity-adjusted.

    Parameters:

    key - the key data.

    offset - the offset to start checking at.

    Returns:

    true if the specified key data is parity-adjusted, false otherwise.

    Throws:

    InvalidKeyException - if the length of the key data starting at offset is less than 8, or the key is null.

  • isWeak

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

    Returns whether the specified key data starting at offset is weak or semi-weak.

    Parameters:

    key - the key data.

    offset - the offset to start checking at.

    Returns:

    true if the specified key data is weak or semi-weak.

    Throws:

    InvalidKeyException - if the length of the key data starting at offset is less than 8, or it is null.