DES

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cryptix.jce.provider.cipher
Class DES

java.lang.Object
  javax.crypto.CipherSpi
      cryptix.jce.provider.cipher.BlockCipher
          cryptix.jce.provider.cipher.DES

public final class DES
extends BlockCipher

DES is a block cipher with an 8 byte block size. The key length is 8 bytes, but only 56 bits are used as the parity bit in each byte is ignored.

This algorithm has been seriously analysed over the last 30 years, and no significant weaknesses have been reported. Its only known flaw is that the key length of 56 bits makes it relatively easy to brute-force it.

To overcome this near-fatal flaw, it is recommended that DES be used in Triple DES mode. The JCA algorithm name for the recommended form of Triple DES is "DES-EDE3".

DES was invented by IBM and first released in 1976. The algorithm is freely usable for both single and triple encryption.

References:

"Chapter 12 Data Encryption Standard," Applied Cryptography, 2nd edition, Bruce Schneier, John Wiley & Sons, 1996.
NIST FIPS PUB 46-2 (supercedes FIPS PUB 46-1), "Data Encryption Standard", U.S. Department of Commerce, December 1993.
http://www.itl.nist.gov/fipspubs/fip46-2.htm

Version:: $Revision: 1.11 $

Field Summary

private static int ALT_KEY_LENGTH


private static int BLOCK_SIZE


private static int INTERNAL_KEY_LENGTH


private static int KEY_LENGTH


private static int ROUNDS


private static int[] SKB
          Table for PC2 permutations in key schedule computation.

private int[] sKey
          The internal key schedule

private static int[] SP_TRANS
          Table for S-boxes and permutations, used in encrypt_base.

Fields inherited from class cryptix.jce.provider.cipher.BlockCipher

Constructor Summary

DES()


Method Summary

protected void coreCrypt(byte[] in, int inOffset, byte[] out, int outOffset)
          Perform a DES encryption or decryption operation of a single block.

protected void coreInit(java.security.Key key, boolean decrypt)


Methods inherited from class cryptix.jce.provider.cipher.BlockCipher

clone, coreGetBlockSize, engineDoFinal, engineDoFinal, engineGetBlockSize, engineGetIV, engineGetKeySize, engineGetOutputSize, engineGetParameters, engineInit, engineInit, engineInit, engineSetMode, engineSetPadding, engineUpdate, engineUpdate

Methods inherited from class javax.crypto.CipherSpi

engineDoFinal, engineUnwrap, engineUpdate, engineWrap

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ROUNDS

private static final int ROUNDS

See Also:: Constant Field Values

BLOCK_SIZE

private static final int BLOCK_SIZE

See Also:: Constant Field Values

KEY_LENGTH

private static final int KEY_LENGTH

See Also:: Constant Field Values

ALT_KEY_LENGTH

private static final int ALT_KEY_LENGTH

See Also:: Constant Field Values

INTERNAL_KEY_LENGTH

private static final int INTERNAL_KEY_LENGTH

See Also:: Constant Field Values

SKB

private static final int[] SKB

Table for PC2 permutations in key schedule computation.

SP_TRANS

private static final int[] SP_TRANS

Table for S-boxes and permutations, used in encrypt_base.

sKey

private int[] sKey

The internal key schedule

Constructor Detail

DES

public DES()

Method Detail

coreInit

protected void coreInit(java.security.Key key,
                        boolean decrypt)
                 throws java.security.InvalidKeyException

Specified by:: coreInit in class BlockCipher

coreCrypt

protected void coreCrypt(byte[] in,
                         int inOffset,
                         byte[] out,
                         int outOffset)

Perform a DES encryption or decryption operation of a single block.

Specified by:: coreCrypt in class BlockCipher