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java.lang.Object
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+--gnu.crypto.cipher.BaseCipher
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+--gnu.crypto.cipher.TripleDES
Triple-DES, 3DES, or DESede is a combined cipher that uses three iterations of the Data Encryption Standard cipher to improve the security (at the cost of speed) of plain DES.
Triple-DES runs the DES algorithm three times with three independent 56 bit keys. To encrypt:
Ci = Ek3 ( Ek2-1 ( Ek1 ( Pi )))
And to decrypt:
Pi = Ek1-1 ( Ek2 ( Ek3-1 ( Ci )))
(The "ede" comes from the encryption operation, which runs Encrypt-Decrypt-Encrypt)
References:
| Field Summary | |
static int |
BLOCK_SIZE
Triple-DES only operates on 64 bit blocks. |
static int |
KEY_SIZE
Triple-DES uses 168 bits of a parity-adjusted 192 bit key. |
| Fields inherited from class gnu.crypto.cipher.BaseCipher |
currentBlockSize, currentKey, defaultBlockSize, defaultKeySize, lock, name |
| Fields inherited from interface gnu.crypto.cipher.IBlockCipher |
CIPHER_BLOCK_SIZE, KEY_MATERIAL |
| Constructor Summary | |
TripleDES()
Default 0-arguments constructor. |
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| Method Summary | |
static void |
adjustParity(byte[] kb,
int offset)
Transform a key so it will be parity adjusted. |
java.util.Iterator |
blockSizes()
Returns an Iterator over the supported block sizes. |
java.lang.Object |
clone()
Returns a clone of this instance. |
void |
decrypt(byte[] in,
int i,
byte[] out,
int o,
java.lang.Object K,
int bs)
Decrypts exactly one block of ciphertext. |
void |
encrypt(byte[] in,
int i,
byte[] out,
int o,
java.lang.Object K,
int bs)
Encrypts exactly one block of plaintext. |
static boolean |
isParityAdjusted(byte[] kb,
int offset)
Tests if a byte array has already been parity adjusted. |
java.util.Iterator |
keySizes()
Returns an Iterator over the supported key sizes. |
java.lang.Object |
makeKey(byte[] kb,
int bs)
Expands a user-supplied key material into a session key for a designated block size. |
| Methods inherited from class gnu.crypto.cipher.BaseCipher |
currentBlockSize, decryptBlock, defaultBlockSize, defaultKeySize, encryptBlock, init, name, reset, selfTest, testKat |
| Methods inherited from class java.lang.Object |
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
public static final int BLOCK_SIZE
public static final int KEY_SIZE
| Constructor Detail |
public TripleDES()
| Method Detail |
public static void adjustParity(byte[] kb,
int offset)
kb - The key bytes to adjust.offset - The starting offset into the key bytes.DES.adjustParity(byte[],int)
public static boolean isParityAdjusted(byte[] kb,
int offset)
kb - The key bytes to test.offset - The starting offset into the key bytes.
true if the bytes in kb starting at
offset are parity adjusted.DES.isParityAdjusted(byte[],int),
adjustParity(byte[],int)public java.lang.Object clone()
IBlockCipherReturns a clone of this instance.
clone in interface IBlockCipherclone in class BaseCipherpublic java.util.Iterator blockSizes()
IBlockCipherReturns an Iterator over the supported block sizes. Each
element returned by this object is an Integer.
Iterator over the supported block sizes.public java.util.Iterator keySizes()
IBlockCipherReturns an Iterator over the supported key sizes. Each element
returned by this object is an Integer.
Iterator over the supported key sizes.
public java.lang.Object makeKey(byte[] kb,
int bs)
throws java.security.InvalidKeyException
IBlockCipherSpiExpands a user-supplied key material into a session key for a designated block size.
kb - the user-supplied key material.bs - the desired block size in bytes.
java.security.InvalidKeyException - if the key data is invalid.
public void encrypt(byte[] in,
int i,
byte[] out,
int o,
java.lang.Object K,
int bs)
IBlockCipherSpiEncrypts exactly one block of plaintext.
in - the plaintext.i - index of in from which to start considering
data.out - the ciphertext.o - index of out from which to store the result.K - the session key to use.bs - the block size to use.
public void decrypt(byte[] in,
int i,
byte[] out,
int o,
java.lang.Object K,
int bs)
IBlockCipherSpiDecrypts exactly one block of ciphertext.
in - the ciphertext.i - index of in from which to start considering
data.out - the plaintext.o - index of out from which to store the result.K - the session key to use.bs - the block size to use.
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For the latest news and information visit The GNU Crypto project |
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