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java.lang.Object | +--xjava.security.IJCE_Traceable | +--xjava.security.Cipher | +--cryptix.provider.cipher.DES
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/CBC", which is implemented by the DES_EDE3 and CBC DES was written by IBM and first released in 1976. The algorithm is freely usable for both single and triple encryption.
References:
Copyright © 1997
Systemics Ltd on behalf of the
Cryptix Development Team.
All rights reserved.
$Revision: 1.6 $
Fields inherited from class xjava.security.Cipher |
DECRYPT, ENCRYPT, UNINITIALIZED |
Fields inherited from class xjava.security.IJCE_Traceable |
tracing |
Constructor Summary | |
DES()
Constructs a DES cipher object, in the UNINITIALIZED state. |
Method Summary | |
(package private) static void |
|
java.lang.Object |
clone()
Always throws a CloneNotSupportedException (cloning of ciphers is not supported for security reasons). |
int[] |
crypt3(int E0,
int E1)
Implements the Unix crypt(3) algorithm. |
protected void |
des(byte[] in,
int inOffset,
byte[] out,
int outOffset,
boolean encrypt)
Encrypts/decrypts a block, of length BLOCK_SIZE. |
int |
engineBlockSize()
SPI: Returns the length of an input block, in bytes. |
void |
engineInitDecrypt(java.security.Key key)
SPI: Initializes this cipher for decryption, using the specified key. |
void |
engineInitEncrypt(java.security.Key key)
SPI: Initializes this cipher for encryption, using the specified key. |
protected int |
engineUpdate(byte[] in,
int inOffset,
int inLen,
byte[] out,
int outOffset)
SPI: This is the main engine method for updating data. |
protected void |
finalize()
Cleans up resources used by this instance, if necessary. |
static LinkStatus |
getLinkStatus()
Gets an object representing the native linking status of this class. |
static void |
main(java.lang.String[] argv)
Entry point for self_test . |
Methods inherited from class xjava.security.IJCE_Traceable |
disableTracing, enableTracing, traceMethod, traceResult, traceResult, traceVoidMethod |
Methods inherited from class java.lang.Object |
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
public DES()
Method Detail |
public static LinkStatus getLinkStatus()
static void()
protected final void finalize()
finalize
in class java.lang.Object
public final java.lang.Object clone() throws java.lang.CloneNotSupportedException
clone
in class Cipher
xjava.security.Cipher
java.lang.CloneNotSupportedException
- if the cipher is not cloneable.public int engineBlockSize()
engineBlockSize
in class Cipher
public void engineInitEncrypt(java.security.Key key) throws java.security.InvalidKeyException
engineInitEncrypt
in class Cipher
key
- the key to use for encryption.java.security.InvalidKeyException
- if one of the following occurs: public void engineInitDecrypt(java.security.Key key) throws java.security.InvalidKeyException, CryptixException
engineInitDecrypt
in class Cipher
key
- the key to use for decryption.java.security.InvalidKeyException
- if one of the following occurs: protected int engineUpdate(byte[] in, int inOffset, int inLen, byte[] out, int outOffset)
in and out may be the same array, and the input and output regions may overlap.
engineUpdate
in class Cipher
in
- the input data.inOffset
- the offset into in specifying where the data starts.inLen
- the length of the subarray.out
- the output array.outOffset
- the offset indicating where to start writing into
the out array.CryptixException
- if the native library is being used, and it
reports an error.protected void des(byte[] in, int inOffset, byte[] out, int outOffset, boolean encrypt)
in
- an array containing the input blockinOffset
- the starting offset of the input blockout
- an array containing the output blockinOffset
- the starting offset of the output blockencrypt
- true to encrypt, false to decryptpublic int[] crypt3(int E0, int E1)
This method is intended only for use by the class cryptix.tools.UnixCrypt, and should not be used directly by applications.
E0
- first 32 bits of input.E1
- second 32 bits of input.public static void main(java.lang.String[] argv)
self_test
.
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