javax.crypto.spec

Class DESKeySpec

Table des matières
  • 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 and Description
      static int DES_KEY_LEN
      The constant which defines the length of a DES key in bytes.

        

    • Constructor Summary

      Constructors 
      Constructor and 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

      Methods 
      Modifier and Type Method and 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.

        

    • 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.

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Document créé le 30/08/2006, dernière modification le 04/03/2020
Source du document imprimé : https://www.gaudry.be/java-api-rf-javax/crypto/spec/DESKeySpec.html

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