Package org.bouncycastle.crypto.paddings

Class PaddedBufferedBlockCipher

  • public class PaddedBufferedBlockCipher
extends BufferedBlockCipher
    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.

    • Constructor Detail

      • PaddedBufferedBlockCipher

        public PaddedBufferedBlockCipher​(BlockCipher cipher,
                                 BlockCipherPadding padding)
        Create a buffered block cipher with the desired padding.
        Parameters:
        cipher - the underlying block cipher this buffering object wraps.
        padding - the padding type.

      • PaddedBufferedBlockCipher

        public PaddedBufferedBlockCipher​(BlockCipher cipher)
        Create a buffered block cipher PKCS7 padding
        Parameters:
        cipher - the underlying block cipher this buffering object wraps.

    • Method Detail

      • init

        public void init​(boolean forEncryption,
                 CipherParameters params)
          throws java.lang.IllegalArgumentException
        initialise the cipher.
        Overrides:
        init in class BufferedBlockCipher
        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.

      • 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.
        Overrides:
        getOutputSize in class BufferedBlockCipher
        Parameters:
        len - the length of the input.
        Returns:
        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.
        Overrides:
        getUpdateOutputSize in class BufferedBlockCipher
        Parameters:
        len - the length of the input.
        Returns:
        the space required to accommodate a call to update with len 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 neccessary.
        Overrides:
        processByte in class BufferedBlockCipher
        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.
        Overrides:
        processBytes in class BufferedBlockCipher
        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. If the buffer is currently full and padding needs to be added a call to doFinal will produce 2 * getBlockSize() bytes.
        Overrides:
        doFinal in class BufferedBlockCipher
        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 we are decrypting and the input is not block size aligned.
        java.lang.IllegalStateException - if the underlying cipher is not initialised.
        InvalidCipherTextException - if padding is expected and not found.