org.bouncycastle.crypto.modes

Class PGPCFBBlockCipher

public class PGPCFBBlockCipher extends Object implements BlockCipher

Implements OpenPGP's rather strange version of Cipher-FeedBack (CFB) mode on top of a simple cipher. For further info see RFC 2440.
Constructor Summary
PGPCFBBlockCipher(BlockCipher cipher, boolean inlineIv)
Basic constructor.
Method Summary
StringgetAlgorithmName()
return the algorithm name and mode.
intgetBlockSize()
return the block size we are operating at.
BlockCiphergetUnderlyingCipher()
return the underlying block cipher that we are wrapping.
voidinit(boolean forEncryption, CipherParameters params)
Initialise the cipher and, possibly, the initialisation vector (IV).
intprocessBlock(byte[] in, int inOff, byte[] out, int outOff)
Process one block of input from the array in and write it to the out array.
voidreset()
reset the chaining vector back to the IV and reset the underlying cipher.

Constructor Detail

PGPCFBBlockCipher

public PGPCFBBlockCipher(BlockCipher cipher, boolean inlineIv)
Basic constructor.

Parameters: cipher the block cipher to be used as the basis of the feedback mode. inlineIv if true this is for PGP CFB with a prepended iv.

Method Detail

getAlgorithmName

public String getAlgorithmName()
return the algorithm name and mode.

Returns: the name of the underlying algorithm followed by "/PGPCFB" and the block size in bits.

getBlockSize

public int getBlockSize()
return the block size we are operating at.

Returns: the block size we are operating at (in bytes).

getUnderlyingCipher

public BlockCipher getUnderlyingCipher()
return the underlying block cipher that we are wrapping.

Returns: the underlying block cipher that we are wrapping.

init

public void init(boolean forEncryption, CipherParameters params)
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.

Parameters: forEncryption if true the cipher is initialised for encryption, if false for decryption. params the key and other data required by the cipher.

Throws: IllegalArgumentException if the params argument is inappropriate.

processBlock

public 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.

Parameters: 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.

Returns: the number of bytes processed and produced.

Throws: DataLengthException if there isn't enough data in in, or space in out. IllegalStateException if the cipher isn't initialised.

reset

public void reset()
reset the chaining vector back to the IV and reset the underlying cipher.