org.bouncycastle.crypto.paddings
Class PaddedBufferedBlockCipher
public class PaddedBufferedBlockCipher
A wrapper class that allows block ciphers to be used to process data in
a piecemeal fashion with padding. The PaddedBufferedBlockCipher
outputs a block only when the buffer is full and more data is being added,
or on a doFinal (unless the current block in the buffer is a pad block).
The default padding mechanism used is the one outlined in PKCS5/PKCS7.
int | doFinal(byte[] out, int outOff) - Process the last block in the buffer.
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int | getOutputSize(int len) - return the minimum size of the output buffer required for an update
plus a doFinal with an input of len bytes.
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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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PaddedBufferedBlockCipher
public PaddedBufferedBlockCipher(BlockCipher cipher)
Create a buffered block cipher PKCS7 padding
cipher
- the underlying block cipher this buffering object wraps.
PaddedBufferedBlockCipher
public PaddedBufferedBlockCipher(BlockCipher cipher,
BlockCipherPadding padding)
Create a buffered block cipher with the desired padding.
cipher
- the underlying block cipher this buffering object wraps.padding
- the padding type.
doFinal
public int doFinal(byte[] out,
int outOff)
throws DataLengthException,
IllegalStateException,
InvalidCipherTextException
Process the last block in the buffer. If the buffer is currently
full and padding needs to be added a call to doFinal will produce
2 * getBlockSize() bytes.
- doFinal in interface BufferedBlockCipher
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.
getOutputSize
public int getOutputSize(int len)
return the minimum size of the output buffer required for an update
plus a doFinal with an input of len bytes.
- getOutputSize in interface BufferedBlockCipher
len
- the length of the input.
- the space required to accommodate a call to update and doFinal
with len bytes of input.
getUpdateOutputSize
public int getUpdateOutputSize(int len)
return the size of the output buffer required for an update
an input of len bytes.
- getUpdateOutputSize in interface BufferedBlockCipher
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.
- init in interface BufferedBlockCipher
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.
- processByte in interface BufferedBlockCipher
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.
- processBytes in interface BufferedBlockCipher
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.