org.bouncycastle.crypto
Class BufferedBlockCipher
java.lang.Object
org.bouncycastle.crypto.BufferedBlockCipher
public class BufferedBlockCipher
extends java.lang.Object
A wrapper class that allows block ciphers to be used to process data in
a piecemeal fashion. The BufferedBlockCipher outputs a block only when the
buffer is full and more data is being added, or on a doFinal.
Note: in the case where the underlying cipher is either a CFB cipher or an
OFB one the last block may not be a multiple of the block size.
int | doFinal(byte[] out, int outOff) - Process the last block in the buffer.
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int | getBlockSize() - return the blocksize for the underlying cipher.
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int | getOutputSize(int len) - return the size of the output buffer required for an update plus a
doFinal with an input of len bytes.
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BlockCipher | getUnderlyingCipher() - return the cipher this object wraps.
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int | getUpdateOutputSize(int len) - return the size of the output buffer required for an update
an input of len bytes.
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void | init(boolean forEncryption, CipherParameters params) - initialise the cipher.
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int | processByte(byte in, byte[] out, int outOff) - process a single byte, producing an output block if neccessary.
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int | processBytes(byte[] in, int inOff, int len, byte[] out, int outOff) - process an array of bytes, producing output if necessary.
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void | reset() - Reset the buffer and cipher.
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bufOff
protected int bufOff
forEncryption
protected boolean forEncryption
partialBlockOkay
protected boolean partialBlockOkay
pgpCFB
protected boolean pgpCFB
BufferedBlockCipher
protected BufferedBlockCipher()
constructor for subclasses
BufferedBlockCipher
public BufferedBlockCipher(BlockCipher cipher)
Create a buffered block cipher without padding.
cipher
- the underlying block cipher this buffering object wraps.
doFinal
public int doFinal(byte[] out,
int outOff)
throws DataLengthException,
IllegalStateException,
InvalidCipherTextException
Process the last block in the buffer.
out
- the array the block currently being held is copied into.outOff
- the offset at which the copying starts.
- the number of output bytes copied to out.
getBlockSize
public int getBlockSize()
return the blocksize for the underlying cipher.
- the blocksize for the underlying cipher.
getOutputSize
public int getOutputSize(int len)
return the size of the output buffer required for an update plus a
doFinal with an input of len bytes.
len
- the length of the input.
- the space required to accommodate a call to update and doFinal
with len bytes of input.
getUnderlyingCipher
public BlockCipher getUnderlyingCipher()
return the cipher this object wraps.
- the cipher this object wraps.
getUpdateOutputSize
public int getUpdateOutputSize(int len)
return the size of the output buffer required for an update
an input of len bytes.
len
- the length of the input.
- the space required to accommodate a call to update
with len bytes of input.
init
public void init(boolean forEncryption,
CipherParameters params)
throws IllegalArgumentException
initialise the cipher.
forEncryption
- if true the cipher is initialised for
encryption, if false for decryption.params
- the key and other data required by the cipher.
processByte
public int processByte(byte in,
byte[] out,
int outOff)
throws DataLengthException,
IllegalStateException
process a single byte, producing an output block if neccessary.
in
- the input byte.out
- the space for any output that might be produced.outOff
- the offset from which the output will be copied.
- the number of output bytes copied to out.
processBytes
public int processBytes(byte[] in,
int inOff,
int len,
byte[] out,
int outOff)
throws DataLengthException,
IllegalStateException
process an array of bytes, producing output if necessary.
in
- the input byte array.inOff
- the offset at which the input data starts.len
- the number of bytes to be copied out of the input array.out
- the space for any output that might be produced.outOff
- the offset from which the output will be copied.
- the number of output bytes copied to out.
reset
public void reset()
Reset the buffer and cipher. After resetting the object is in the same
state as it was after the last init (if there was one).