Package org.bouncycastle.crypto.modes

Class OldCTSBlockCipher

  • public class OldCTSBlockCipher
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.

    This version applies the CTS algorithm from one block up, rather than following the errata update issued in 2004, where CTS mode is applied from greater than 1 block up and the first block is processed using CBC mode.

    • Constructor Detail

      • OldCTSBlockCipher

        public OldCTSBlockCipher​(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).