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Class cryptix.security.CipherFeedback
java.lang.Object
|
+----cryptix.security.StreamCipher
|
+----cryptix.security.CipherFeedback
- public class CipherFeedback
- extends StreamCipher
Note: CipherFeedback is deprecated.
Implements a byte-based stream cipher using n-bit CFB with an
n-bit-sized block cipher.
The full block size of the supplied cipher is used for the
Cipher Feedback Mode. The bytes supplied are processed and returned
immediately.
Copyright © 1997
Systemics Ltd on behalf of the
Cryptix Development Team.
All rights reserved.
$Revision: 1.3 $
- Author:
- Systemics Ltd, David Hopwood
- See Also:
- CFB
-
cipher
-
-
currentByte
-
-
ivBlock
-
-
length
-
-
xorBlock
-
-
CipherFeedback(BlockCipher, byte[])
- This implements variant A: a unique initial value for the
feedback register must be provided in the constructor.
-
decrypt(byte[], int, byte[], int, int)
- This function decrypts a block of data.
-
encrypt(byte[], int, byte[], int, int)
- This function encrypts a block of data.
-
keyLength()
- This function returns the length of the key for this cipher.
-
reset(byte[])
- Reset the stream feedback register with a new unique IV
and sets position in stream back to zero.
ivBlock
protected byte ivBlock[]
xorBlock
protected byte xorBlock[]
cipher
protected BlockCipher cipher
currentByte
protected int currentByte
length
protected int length
CipherFeedback
public CipherFeedback(BlockCipher cipher0,
byte iv0[])
- This implements variant A: a unique initial value for the
feedback register must be provided in the constructor.
If the IV is not unique, the plaintext can be recovered.
- Parameters:
- cipher0 - the block cipher to use
- iv0 - the initial value for the shift register (IV)
keyLength
public int keyLength()
- This function returns the length of the key for this cipher.
- Overrides:
- keyLength in class StreamCipher
reset
public void reset(byte iv0[])
- Reset the stream feedback register with a new unique IV
and sets position in stream back to zero.
- Parameters:
- iv0 - the initial value for the shift register (IV)
encrypt
public void encrypt(byte in[],
int in_offset,
byte out[],
int out_offset,
int length)
- This function encrypts a block of data.
The contents of the array in will not be changed,
but will instead store the result in the array out.
The arrays can, however, be the same.
- Parameters:
- in - the plain text to be encrypted.
- in_offset - the offset within the in buffer.
- out - where the encrypted cipher text will be stored.
- out_offset - the offset within the out buffer.
- length - the length to encrypt.
- Overrides:
- encrypt in class StreamCipher
decrypt
public void decrypt(byte in[],
int in_offset,
byte out[],
int out_offset,
int length)
- This function decrypts a block of data.
The contents of the array in will not be changed,
but will instead store the result in the array out.
The arrays can, however, be the same.
- Parameters:
- in - the cipher text to be decrypted.
- in_offset - the offset within the in buffer.
- out - where the decrypted plain text will be stored.
- out_offset - the offset within the out buffer.
- length - the length to decrypt.
- Overrides:
- decrypt in class StreamCipher
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