Package org.bouncycastle.crypto.modes

Class CFBBlockCipher

    • Constructor Summary

      Constructors 
      Constructor Description
      CFBBlockCipher​(BlockCipher cipher, int bitBlockSize)
      Basic constructor.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected byte calculateByte​(byte in)  
      int decryptBlock​(byte[] in, int inOff, byte[] out, int outOff)
      Do the appropriate processing for CFB mode decryption.
      int encryptBlock​(byte[] in, int inOff, byte[] out, int outOff)
      Do the appropriate processing for CFB mode encryption.
      java.lang.String getAlgorithmName()
      return the algorithm name and mode.
      int getBlockSize()
      return the block size we are operating at.
      byte[] getCurrentIV()
      Return the current state of the initialisation vector.
      void init​(boolean encrypting, CipherParameters params)
      Initialise the cipher and, possibly, the initialisation vector (IV).
      int processBlock​(byte[] in, int inOff, byte[] out, int outOff)
      Process one block of input from the array in and write it to the out array.
      void reset()
      reset the chaining vector back to the IV and reset the underlying cipher.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • CFBBlockCipher

        public CFBBlockCipher​(BlockCipher cipher,
                      int bitBlockSize)
        Basic constructor.
        Parameters:
        cipher - the block cipher to be used as the basis of the feedback mode.
        bitBlockSize - the block size in bits (note: a multiple of 8)

    • Method Detail

      • init

        public void init​(boolean encrypting,
                 CipherParameters params)
          throws java.lang.IllegalArgumentException
        Initialise the cipher and, possibly, the initialisation vector (IV). If an IV isn't passed as part of the parameter, the IV will be all zeros. An IV which is too short is handled in FIPS compliant fashion.
        Parameters:
        encrypting - 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.

      • getAlgorithmName

        public java.lang.String getAlgorithmName()
        return the algorithm name and mode.
        Returns:
        the name of the underlying algorithm followed by "/CFB" and the block size in bits.

      • getBlockSize

        public int getBlockSize()
        return the block size we are operating at.
        Returns:
        the block size we are operating at (in bytes).

      • processBlock

        public int processBlock​(byte[] in,
                        int inOff,
                        byte[] out,
                        int outOff)
                 throws DataLengthException,
                        java.lang.IllegalStateException
        Process one block of input from the array in and write it to the out array.
        Parameters:
        in - the array containing the input data.
        inOff - offset into the in array the data starts at.
        out - the array the output data will be copied into.
        outOff - the offset into the out array the output will start at.
        Returns:
        the number of bytes processed and produced.
        Throws:
        DataLengthException - if there isn't enough data in in, or space in out.
        java.lang.IllegalStateException - if the cipher isn't initialised.

      • encryptBlock

        public int encryptBlock​(byte[] in,
                        int inOff,
                        byte[] out,
                        int outOff)
                 throws DataLengthException,
                        java.lang.IllegalStateException
        Do the appropriate processing for CFB mode encryption.
        Parameters:
        in - the array containing the data to be encrypted.
        inOff - offset into the in array the data starts at.
        out - the array the encrypted data will be copied into.
        outOff - the offset into the out array the output will start at.
        Returns:
        the number of bytes processed and produced.
        Throws:
        DataLengthException - if there isn't enough data in in, or space in out.
        java.lang.IllegalStateException - if the cipher isn't initialised.

      • decryptBlock

        public int decryptBlock​(byte[] in,
                        int inOff,
                        byte[] out,
                        int outOff)
                 throws DataLengthException,
                        java.lang.IllegalStateException
        Do the appropriate processing for CFB mode decryption.
        Parameters:
        in - the array containing the data to be decrypted.
        inOff - offset into the in array the data starts at.
        out - the array the encrypted data will be copied into.
        outOff - the offset into the out array the output will start at.
        Returns:
        the number of bytes processed and produced.
        Throws:
        DataLengthException - if there isn't enough data in in, or space in out.
        java.lang.IllegalStateException - if the cipher isn't initialised.

      • getCurrentIV

        public byte[] getCurrentIV()
        Return the current state of the initialisation vector.
        Returns:
        current IV

      • reset

        public void reset()
        reset the chaining vector back to the IV and reset the underlying cipher.