Package org.bouncycastle.crypto

## Class BufferedBlockCipher

- java.lang.Object
- - org.bouncycastle.crypto.BufferedBlockCipher

- Direct Known Subclasses:
    `CTSBlockCipher`, `KXTSBlockCipher`, `NISTCTSBlockCipher`, `OldCTSBlockCipher`, `PaddedBlockCipher`, `PaddedBufferedBlockCipher`

      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.

- - ### Field Summary

    Fields
    Modifier and Type | Field | Description
    --- | --- | ---
    `protected byte[]` | `buf` |
    `protected int` | `bufOff` |
    `protected BlockCipher` | `cipher` |
    `protected boolean` | `forEncryption` |
    `protected boolean` | `partialBlockOkay` |
    `protected boolean` | `pgpCFB` |

  - ### Constructor Summary

    Constructors
    Modifier | Constructor | Description
    --- | --- | ---
    `protected` | `BufferedBlockCipher()` | constructor for subclasses
    `` | `BufferedBlockCipher​(BlockCipher cipher)` | Create a buffered block cipher without padding.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `int` | `doFinal​(byte[] out, int outOff)` | Process the last block in the buffer.
    `int` | `getBlockSize()` | return the blocksize for the underlying cipher.
    `int` | `getOutputSize​(int length)` | return the size of the output buffer required for an update plus a doFinal with an input of 'length' bytes.
    `BlockCipher` | `getUnderlyingCipher()` | return the cipher this object wraps.
    `int` | `getUpdateOutputSize​(int len)` | return the size of the output buffer required for an update an input of len bytes.
    `void` | `init​(boolean forEncryption, CipherParameters params)` | initialise the cipher.
    `int` | `processByte​(byte in, byte[] out, int outOff)` | process a single byte, producing an output block if necessary.
    `int` | `processBytes​(byte[] in, int inOff, int len, byte[] out, int outOff)` | process an array of bytes, producing output if necessary.
    `void` | `reset()` | Reset the buffer and cipher.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### buf

          protected byte[] buf

    - #### bufOff

          protected int bufOff

    - #### forEncryption

          protected boolean forEncryption

    - #### cipher

          protected BlockCipher cipher

    - #### partialBlockOkay

          protected boolean partialBlockOkay

    - #### pgpCFB

          protected boolean pgpCFB

  - ### Constructor Detail

    - #### BufferedBlockCipher

          protected BufferedBlockCipher()

      constructor for subclasses

    - #### BufferedBlockCipher

          public BufferedBlockCipher​(BlockCipher cipher)

      Create a buffered block cipher without padding.
      Parameters:
        `cipher` - the underlying block cipher this buffering object wraps.

  - ### Method Detail

    - #### getUnderlyingCipher

          public BlockCipher getUnderlyingCipher()

      return the cipher this object wraps.
      Returns:
        the cipher this object wraps.

    - #### init

          public void init​(boolean forEncryption,
                           CipherParameters params)
                    throws java.lang.IllegalArgumentException

      initialise the cipher.
      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:
        `java.lang.IllegalArgumentException` - if the params argument is inappropriate.

    - #### getBlockSize

          public int getBlockSize()

      return the blocksize for the underlying cipher.
      Returns:
        the blocksize for the underlying cipher.

    - #### getUpdateOutputSize

          public int getUpdateOutputSize​(int len)

      return the size of the output buffer required for an update an input of len bytes.
      Parameters:
        `len` - the length of the input.
      Returns:
        the space required to accommodate a call to update with len bytes of input.

    - #### getOutputSize

          public int getOutputSize​(int length)

      return the size of the output buffer required for an update plus a doFinal with an input of 'length' bytes.
      Parameters:
        `length` - the length of the input.
      Returns:
        the space required to accommodate a call to update and doFinal with 'length' bytes of input.

    - #### processByte

          public int processByte​(byte in,
                                 byte[] out,
                                 int outOff)
                          throws DataLengthException,
                                 java.lang.IllegalStateException

      process a single byte, producing an output block if necessary.
      Parameters:
        `in` - the input byte.
        `out` - the space for any output that might be produced.
        `outOff` - the offset from which the output will be copied.
      Returns:
        the number of output bytes copied to out.
      Throws:
        `DataLengthException` - if there isn't enough space in out.
        `java.lang.IllegalStateException` - if the cipher isn't initialised.

    - #### processBytes

          public int processBytes​(byte[] in,
                                  int inOff,
                                  int len,
                                  byte[] out,
                                  int outOff)
                           throws DataLengthException,
                                  java.lang.IllegalStateException

      process an array of bytes, producing output if necessary.
      Parameters:
        `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.
      Returns:
        the number of output bytes copied to out.
      Throws:
        `DataLengthException` - if there isn't enough space in out.
        `java.lang.IllegalStateException` - if the cipher isn't initialised.

    - #### doFinal

          public int doFinal​(byte[] out,
                             int outOff)
                      throws DataLengthException,
                             java.lang.IllegalStateException,
                             InvalidCipherTextException

      Process the last block in the buffer.
      Parameters:
        `out` - the array the block currently being held is copied into.
        `outOff` - the offset at which the copying starts.
      Returns:
        the number of output bytes copied to out.
      Throws:
        `DataLengthException` - if there is insufficient space in out for the output, or the input is not block size aligned and should be.
        `java.lang.IllegalStateException` - if the underlying cipher is not initialised.
        `InvalidCipherTextException` - if padding is expected and not found.
        `DataLengthException` - if the input is not block size aligned.

    - #### 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).