Package org.bouncycastle.crypto.modes

Class NISTCTSBlockCipher

  • public class NISTCTSBlockCipher
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 class implements the NIST version as documented in "Addendum to NIST SP 800-38A, Recommendation for Block Cipher Modes of Operation: Three Variants of Ciphertext Stealing for CBC Mode"

    • Constructor Summary

      Constructors 
      Constructor Description
      NISTCTSBlockCipher​(int type, BlockCipher cipher)
      Create a buffered block cipher that uses NIST Cipher Text Stealing

    • 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 getOutputSize​(int len)
      return the size of the output buffer required for an update plus a doFinal with an input of len bytes.
      int getUpdateOutputSize​(int len)
      return the size of the output buffer required for an update an input of len bytes.
      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.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • NISTCTSBlockCipher

        public NISTCTSBlockCipher​(int type,
                          BlockCipher cipher)
        Create a buffered block cipher that uses NIST Cipher Text Stealing
        Parameters:
        type - type of CTS mode (CS1, CS2, or CS3)
        cipher - the underlying block cipher used to create the CBC block cipher this cipher uses..

    • 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).