public class CFBBlockCipher extends StreamBlockCipher
Constructor and Description |
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CFBBlockCipher(BlockCipher cipher,
int bitBlockSize)
Basic constructor.
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Modifier and Type | Method and Description |
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protected byte |
calculateByte(byte in) |
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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java.lang.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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byte[] |
getCurrentIV()
Return the current state of the initialisation vector.
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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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getUnderlyingCipher, processBytes, returnByte
public CFBBlockCipher(BlockCipher cipher, int bitBlockSize)
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)public void init(boolean encrypting, CipherParameters params) throws java.lang.IllegalArgumentException
encrypting
- if true the cipher is initialised for
encryption, if false for decryption.params
- the key and other data required by the cipher.java.lang.IllegalArgumentException
- if the params argument is
inappropriate.public java.lang.String getAlgorithmName()
protected byte calculateByte(byte in) throws DataLengthException, java.lang.IllegalStateException
calculateByte
in class StreamBlockCipher
DataLengthException
java.lang.IllegalStateException
public int getBlockSize()
public int processBlock(byte[] in, int inOff, byte[] out, int outOff) throws DataLengthException, java.lang.IllegalStateException
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.DataLengthException
- if there isn't enough data in in, or
space in out.java.lang.IllegalStateException
- if the cipher isn't initialised.public int encryptBlock(byte[] in, int inOff, byte[] out, int outOff) throws DataLengthException, java.lang.IllegalStateException
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.DataLengthException
- if there isn't enough data in in, or
space in out.java.lang.IllegalStateException
- if the cipher isn't initialised.public int decryptBlock(byte[] in, int inOff, byte[] out, int outOff) throws DataLengthException, java.lang.IllegalStateException
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.DataLengthException
- if there isn't enough data in in, or
space in out.java.lang.IllegalStateException
- if the cipher isn't initialised.public byte[] getCurrentIV()
public void reset()