Java™ Platform
Standard Ed. 6

javax.crypto.spec
Class DESKeySpec

java.lang.Object
  extended by 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
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.

Java™ Platform
Standard Ed. 6

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