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DESKeySpec (Java 2 Platform SE v1.4.1) - JDK 5 Documentation v1.4.1, Java 2 SDK 英文文档

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javax.crypto.spec
Class DESKeySpec

java.lang.Object
  |
  +--javax.crypto.spec.DESKeySpec

All Implemented Interfaces:

KeySpec

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public class DESKeySpec

extends Object

implements KeySpec

This class specifies a DES key.

Since:

1.4

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

 

Constructor Summary

DESKeySpec(byte[] key)           Uses the first 8 bytes in key as the key material for the DES key.

DESKeySpec(byte[] key, int offset)           Uses 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

Uses 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.

Throws:

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

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DESKeySpec

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

Uses 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.

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

Throws:

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.

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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, starting at offset inclusive, is shorter than 8 bytes.

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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, starting at offset inclusive, is shorter than 8 bytes.

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.