Package org.bouncycastle.crypto.modes

## Class CBCBlockCipher

- java.lang.Object
- - org.bouncycastle.crypto.modes.CBCBlockCipher

- All Implemented Interfaces:
    `BlockCipher`

      public class CBCBlockCipher
      extends java.lang.Object
      implements BlockCipher

  implements Cipher-Block-Chaining (CBC) mode on top of a simple cipher.

- - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `CBCBlockCipher​(BlockCipher cipher)` | Basic constructor.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `java.lang.String` | `getAlgorithmName()` | return the algorithm name and mode.
    `int` | `getBlockSize()` | return the block size of the underlying cipher.
    `BlockCipher` | `getUnderlyingCipher()` | return the underlying block cipher that we are wrapping.
    `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

    - #### CBCBlockCipher

          public CBCBlockCipher​(BlockCipher cipher)

      Basic constructor.
      Parameters:
        `cipher` - the block cipher to be used as the basis of chaining.

  - ### Method Detail

    - #### getUnderlyingCipher

          public BlockCipher getUnderlyingCipher()

      return the underlying block cipher that we are wrapping.
      Returns:
        the underlying block cipher that we are wrapping.

    - #### 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.
      Specified by:
        `init` in interface `BlockCipher`
      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`
      Returns:
        the name of the underlying algorithm followed by "/CBC".

    - #### getBlockSize

          public int getBlockSize()

      return the block size of the underlying cipher.
      Specified by:
        `getBlockSize` in interface `BlockCipher`
      Returns:
        the block size of the underlying cipher.

    - #### 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.

    - #### reset

          public void reset()

      reset the chaining vector back to the IV and reset the underlying cipher.
      Specified by:
        `reset` in interface `BlockCipher`