Package org.bouncycastle.crypto

Class 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.

    • 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

      • 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).