com.motorola.iden.provider
Class DESede

java.lang.Object
  |
  +--com.motorola.iden.crypto.CipherSpi
        |
        +--com.motorola.iden.provider.DESede

public final class DESede

extends CipherSpi

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

DESede is a block cipher with an 8 byte block size. The key length is 24 bytes for triple encryption. The parity of all DESede keys is ignored.

For triple encryption, please use algorithm name "DESede". Interface com.motorola.iden.security.Key must be implemented by end user.

DESede support mode "ECB","CBC","CFB" and "OFB". OFB mode is not supported on Gemini. Mode "CBC","CFB" and "OFB" have IV. IV can be initialized by user or generated by system. PKCS5Padding is supported by default.

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© Copyright 2002 - 2004 Motorola, Inc. All Rights Reserved.

See Also:

[CipherSpi]

Field Summary

static int

blocksize The blocksize of DES.

Constructor Summary

DESede()

Method Summary

protected byte[]	engineDoFinal(byte[] input, int inputOffset, int inputLen) Finalizes cipher.
protected int	engineGetBlockSize() Gets the bloksize of the cipher.
protected byte[]	engineGetIV() Gets iv.
protected void	engineInit(int opmode, Key key, AlgorithmParameterSpec params, SecureRandom random) Initializes security builder.
protected void	engineSetMode(java.lang.String mode) Sets the mode of the cipher(ECB,CBC,CFB or OFB).
protected void	engineSetPadding(java.lang.String padding) Sets the Padding of the cipher.
protected byte[]	engineUpdate(byte[] input, int inputOffset, int inputLen) Updates cipher.
protected void	finalize()

Methods inherited from class java.lang.Object

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

Field Detail

blocksize

public static final int blocksize

The blocksize of DES.

DES is a block cipher with an 8 byte block size.

Constructor Detail

DESede

public DESede()

Method Detail

engineSetMode

protected void engineSetMode(java.lang.String mode)
                      throws NoSuchAlgorithmException

Sets the mode of the cipher(ECB,CBC,CFB or OFB).

Overrides:

engineSetMode in class CipherSpi

Parameters:

String - mode. Mode ECB is set defaultly when parameter mode is null.

Returns:

void.

Throws:

NoSuchAlgorithmException - if the requested mode mechanism does not exist

engineSetPadding

protected void engineSetPadding(java.lang.String padding)
                         throws NoSuchPaddingException

Sets the Padding of the cipher.

Overrides:

engineSetPadding in class CipherSpi

Parameters:

String - padding. PKCS5Padding is set defaultly when parameter padding is null.

Throws:

NoSuchPaddingException - if the requested padding mechanism does not exist

engineGetBlockSize

protected int engineGetBlockSize()

Gets the bloksize of the cipher.

Overrides:

engineGetBlockSize in class CipherSpi

Parameters:

viod. -

Returns:

int blocksize (bytes)..

engineGetIV

protected byte[] engineGetIV()

Gets iv.

Overrides:

engineGetIV in class CipherSpi

Returns:

byte[] iv. (null when at mode ECB)

engineInit

protected void engineInit(int opmode,
                          Key key,
                          AlgorithmParameterSpec params,
                          SecureRandom random)
                   throws InvalidKeyException,
                          InvalidAlgorithmParameterException

Initializes security builder.

Overrides:

engineInit in class CipherSpi

Parameters:

opmode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE,

key - the encryption key

params - the algorithm parameters

random - the source of randomness, ignored in this implementation.

Returns:

void.

Throws:

InvalidKeyException - if the given key is inappropriate for initializing this cipher

InvalidAlgorithmParameterException - if the given algorithm parameters are inappropriate for this cipher, or if this cipher is being initialized for decryption and requires algorithm parameters and params is null.

engineUpdate

protected byte[] engineUpdate(byte[] input,
                              int inputOffset,
                              int inputLen)

Updates cipher.

Overrides:

engineUpdate in class CipherSpi

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

Returns:

the new buffer with the result, or null if the underlying cipher is a block cipher and the input data is too short to result in a new block.

engineDoFinal

protected byte[] engineDoFinal(byte[] input,
                               int inputOffset,
                               int inputLen)
                        throws IllegalBlockSizeException,
                               BadPaddingException

Finalizes cipher.

Overrides:

engineDoFinal in class CipherSpi

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

Returns:

the new buffer with the result

Throws:

IllegalBlockSizeException - if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size

BadPaddingException - if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes

finalize

protected void finalize()

Overrides:

finalize in class java.lang.Object