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java.lang.Objectxjava.security.IJCE_Traceable
xjava.security.Cipher
xjava.security.Mode
cryptix.provider.mode.FeedbackMode
cryptix.provider.mode.CFB
cryptix.provider.mode.CFB_PGP
public class CFB_PGP
Use of this feedback mode is deprecated, use it for compatibility only!
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 $
Field Summary |
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Fields inherited from class cryptix.provider.mode.FeedbackMode |
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currentByte, ivBlock, ivStart, length |
Fields inherited from class xjava.security.Mode |
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cipher |
Fields inherited from class xjava.security.Cipher |
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DECRYPT, ENCRYPT, UNINITIALIZED |
Constructor Summary | |
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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). |
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CFB_PGP(Cipher cipher)
Constructs a CFB-PGP cipher, assuming that the IV will be provided as the first getInitializationVectorLength()
bytes of the stream. |
Method Summary | |
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protected int |
engineUpdate(byte[] in,
int inOffset,
int inLen,
byte[] out,
int outOffset)
SPI: This is the main engine method for updating data. |
Methods inherited from class cryptix.provider.mode.CFB |
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engineBlockSize, engineInitDecrypt, engineInitEncrypt, engineSetCipher, next_block |
Methods inherited from class cryptix.provider.mode.FeedbackMode |
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getInitializationVector, getInitializationVectorLength, setInitializationVector |
Methods inherited from class xjava.security.Mode |
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engineGetParameter, engineSetParameter, getAlgorithms, getAlgorithms, getInstance, getInstance, toString |
Methods inherited from class java.lang.Object |
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equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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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 == null
IllegalBlockSizeException
- if cipher.getPlaintextBlockSize() !=
cipher.getCiphertextBlockSize()Method Detail |
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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.
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