org.bouncycastle.crypto.modes
Class CFBBlockCipher
java.lang.Object
org.bouncycastle.crypto.modes.CFBBlockCipher
- BlockCipher
public class CFBBlockCipher
extends java.lang.Object
implements a Cipher-FeedBack (CFB) mode on top of a simple cipher.
int | decryptBlock(byte[] in, int inOff, byte[] out, int outOff) - Do the appropriate processing for CFB mode decryption.
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int | encryptBlock(byte[] in, int inOff, byte[] out, int outOff) - Do the appropriate processing for CFB mode encryption.
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String | getAlgorithmName() - return the algorithm name and mode.
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int | getBlockSize() - return the block size we are operating at.
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BlockCipher | getUnderlyingCipher() - return the underlying block cipher that we are wrapping.
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void | init(boolean encrypting, CipherParameters params) - Initialise the cipher and, possibly, the initialisation vector (IV).
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int | processBlock(byte[] in, int inOff, byte[] out, int outOff) - Process one block of input from the array in and write it to
the out array.
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void | reset() - reset the chaining vector back to the IV and reset the underlying
cipher.
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CFBBlockCipher
public CFBBlockCipher(BlockCipher cipher,
int bitBlockSize)
Basic constructor.
cipher
- the block cipher to be used as the basis of the
feedback mode.bitBlockSize
- the block size in bits (note: a multiple of 8)
decryptBlock
public int decryptBlock(byte[] in,
int inOff,
byte[] out,
int outOff)
throws DataLengthException,
IllegalStateException
Do the appropriate processing for CFB mode decryption.
in
- the array containing the data to be decrypted.inOff
- offset into the in array the data starts at.out
- the array the encrypted data will be copied into.outOff
- the offset into the out array the output will start at.
- the number of bytes processed and produced.
DataLengthException
- if there isn't enough data in in, or
space in out.
encryptBlock
public int encryptBlock(byte[] in,
int inOff,
byte[] out,
int outOff)
throws DataLengthException,
IllegalStateException
Do the appropriate processing for CFB mode encryption.
in
- the array containing the data to be encrypted.inOff
- offset into the in array the data starts at.out
- the array the encrypted data will be copied into.outOff
- the offset into the out array the output will start at.
- the number of bytes processed and produced.
DataLengthException
- if there isn't enough data in in, or
space in out.
getAlgorithmName
public String getAlgorithmName()
return the algorithm name and mode.
- getAlgorithmName in interface BlockCipher
- the name of the underlying algorithm followed by "/CFB"
and the block size in bits.
getBlockSize
public int getBlockSize()
return the block size we are operating at.
- getBlockSize in interface BlockCipher
- the block size we are operating at (in bytes).
getUnderlyingCipher
public BlockCipher getUnderlyingCipher()
return the underlying block cipher that we are wrapping.
- the underlying block cipher that we are wrapping.
init
public void init(boolean encrypting,
CipherParameters params)
throws IllegalArgumentException
Initialise the cipher and, possibly, the initialisation vector (IV).
If an IV isn't passed as part of the parameter, the IV will be all zeros.
An IV which is too short is handled in FIPS compliant fashion.
- init in interface BlockCipher
encrypting
- if true the cipher is initialised for
encryption, if false for decryption.params
- the key and other data required by the cipher.
processBlock
public int processBlock(byte[] in,
int inOff,
byte[] out,
int outOff)
throws DataLengthException,
IllegalStateException
Process one block of input from the array in and write it to
the out array.
- processBlock in interface BlockCipher
in
- the array containing the input data.inOff
- offset into the in array the data starts at.out
- the array the output data will be copied into.outOff
- the offset into the out array the output will start at.
- the number of bytes processed and produced.
DataLengthException
- if there isn't enough data in in, or
space in out.
reset
public void reset()
reset the chaining vector back to the IV and reset the underlying
cipher.
- reset in interface BlockCipher