Class DESKeySpec

All Implemented Interfaces:
KeySpec
public class DESKeySpec
extends Object
implements KeySpec

This class specifies a DES key.

Since:
1.4

Field Summary

Fields
Modifier and Type Field Description
static int DES_KEY_LEN

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

Constructor Summary

Constructors
Constructor 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

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type Method 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 declared in 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 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.

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 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.