Package org.bouncycastle.crypto.modes

Class CTSBlockCipher

  • public class CTSBlockCipher
extends BufferedBlockCipher
    A Cipher Text Stealing (CTS) mode cipher. CTS allows block ciphers to be used to produce cipher text which is the same length as the plain text.

    • Constructor Detail

      • CTSBlockCipher

        public CTSBlockCipher​(BlockCipher cipher)
        Create a buffered block cipher that uses Cipher Text Stealing
        Parameters:
        cipher - the underlying block cipher this buffering object wraps.

    • Method Detail

      • 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.

      • 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.
        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.

      • 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.
        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.
        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.
        java.lang.IllegalStateException - if the underlying cipher is not initialised.
        InvalidCipherTextException - if cipher text decrypts wrongly (in case the exception will never get thrown).