Package org.bouncycastle.crypto.modes

Class CFBBlockCipher

    • Constructor Detail

      • CFBBlockCipher

        public CFBBlockCipher​(BlockCipher cipher,
                      int bitBlockSize)
        Deprecated.
        use the equivalent CFBBlockCipher.newInstance() static method.
        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

      • newInstance

        public static CFBModeCipher newInstance​(BlockCipher cipher,
                                        int blockSize)
        Return a new CFB mode cipher based on the passed in base cipher
        Parameters:
        cipher - the base cipher for the CFB mode.
        blockSize - the block size (in bits) used for the CFB mode.

      • 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.
        Specified by:
        init in interface BlockCipher
        Specified by:
        init in interface StreamCipher
        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.
        Specified by:
        getAlgorithmName in interface BlockCipher
        Specified by:
        getAlgorithmName in interface StreamCipher
        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.
        Specified by:
        getBlockSize in interface BlockCipher
        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.
        Specified by:
        processBlock in interface BlockCipher
        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.
        Specified by:
        reset in interface BlockCipher
        Specified by:
        reset in interface StreamCipher