public class CFB_PGP extends CFB
This class implements PGP's (i.e. Zimmerman's) non-standard CFB mode. (For the standard method, see the Applied Cryptography reference below). It replaces cryptix.pgp.CFB in version 2.2, and cryptix.pgp.PGP_CFB in version Cryptix 2.2.0a.
The differences between this and standard CFB are that:
update
or crypt
), the CFB
shift register is encrypted, regardless of the current position
within a block.
Note that it is unusual for the output of a cipher to depend on the exact boundaries between data passed to each encryption/decryption call. Normally, the lengths of data passed to each call do not matter as long as they make up the correct input when concatenated together - but this class is an exception.
As a result, using this mode with CipherInputStream and CipherOutputStream may produce unexpected output, and is not recommended.
References
Copyright © 1997
Systemics Ltd on behalf of the
Cryptix Development Team.
All rights reserved.
$Revision: 1.9 $
currentByte, ivBlock, ivStart, length
DECRYPT, ENCRYPT, UNINITIALIZED
Constructor and Description |
---|
CFB_PGP()
Constructs a CFB-PGP cipher, assuming that the IV will be provided
as the first
getInitializationVectorLength()
bytes of the stream (it will be visible as cleartext at the start
of the output stream). |
CFB_PGP(Cipher cipher)
Constructs a CFB-PGP cipher, assuming that the IV will be provided
as the first
getInitializationVectorLength()
bytes of the stream. |
Modifier and Type | Method and Description |
---|---|
protected int |
engineUpdate(byte[] in,
int inOffset,
int inLen,
byte[] out,
int outOffset)
SPI: This is the main engine method for updating data.
|
engineBlockSize, engineInitDecrypt, engineInitEncrypt, engineSetCipher, next_block
getInitializationVector, getInitializationVectorLength, setInitializationVector
engineGetParameter, engineSetParameter, getAlgorithms, getAlgorithms, getInstance, getInstance, toString
blockSize, clone, crypt, crypt, crypt, doFinal, doFinal, doFinal, doFinal, engineCiphertextBlockSize, engineCrypt, engineInBufferSize, engineOutBufferSize, enginePlaintextBlockSize, engineSetPaddingScheme, getAlgorithm, getCiphertextBlockSize, getInputBlockSize, getInstance, getMode, getOutputBlockSize, getPadding, getPaddingScheme, getParameter, getPlaintextBlockSize, getProvider, getState, inBufferSize, inBufferSizeFinal, initDecrypt, initEncrypt, isPaddingBlockCipher, outBufferSize, outBufferSizeFinal, setParameter, update, update, update, update
public CFB_PGP()
getInitializationVectorLength()
bytes of the stream (it will be visible as cleartext at the start
of the output stream).
The IV must be unique during the lifetime of the key. If it is not unique, at least the first block of the plaintext can be recovered.
public CFB_PGP(Cipher cipher)
getInitializationVectorLength()
bytes of the stream. See the previous constructor for more details.java.lang.NullPointerException
- if cipher == nullIllegalBlockSizeException
- if cipher.getPlaintextBlockSize() !=
cipher.getCiphertextBlockSize()protected int engineUpdate(byte[] in, int inOffset, int inLen, byte[] out, int outOffset)
CFB
in
and out
may be the same array, and the
input and output regions may overlap.
engineUpdate
in class CFB
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.