Package org.bouncycastle.crypto

## Interface StreamCipher

- All Known Subinterfaces:
    `SkippingStreamCipher`
  All Known Implementing Classes:
    `CFBBlockCipher`, `ChaCha7539Engine`, `ChaChaEngine`, `G3413CFBBlockCipher`, `G3413CTRBlockCipher`, `G3413OFBBlockCipher`, `GCFBBlockCipher`, `GOFBBlockCipher`, `Grain128Engine`, `Grainv1Engine`, `HC128Engine`, `HC256Engine`, `ISAACEngine`, `KCTRBlockCipher`, `OFBBlockCipher`, `RC4Engine`, `Salsa20Engine`, `SICBlockCipher`, `StreamBlockCipher`, `VMPCEngine`, `VMPCKSA3Engine`, `XSalsa20Engine`, `Zuc128CoreEngine`, `Zuc128Engine`, `Zuc256CoreEngine`, `Zuc256Engine`

      public interface StreamCipher

  the interface stream ciphers conform to.

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `java.lang.String` | `getAlgorithmName()` | Return the name of the algorithm the cipher implements.
    `void` | `init​(boolean forEncryption, CipherParameters params)` | Initialise the cipher.
    `int` | `processBytes​(byte[] in, int inOff, int len, byte[] out, int outOff)` | process a block of bytes from in putting the result into out.
    `void` | `reset()` | reset the cipher.
    `byte` | `returnByte​(byte in)` | encrypt/decrypt a single byte returning the result.

- - ### Method Detail

    - #### init

          void init​(boolean forEncryption,
                    CipherParameters params)
             throws java.lang.IllegalArgumentException

      Initialise the cipher.
      Parameters:
        `forEncryption` - 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

          java.lang.String getAlgorithmName()

      Return the name of the algorithm the cipher implements.
      Returns:
        the name of the algorithm the cipher implements.

    - #### returnByte

          byte returnByte​(byte in)

      encrypt/decrypt a single byte returning the result.
      Parameters:
        `in` - the byte to be processed.
      Returns:
        the result of processing the input byte.

    - #### processBytes

          int processBytes​(byte[] in,
                           int inOff,
                           int len,
                           byte[] out,
                           int outOff)
                    throws DataLengthException

      process a block of bytes from in putting the result into out.
      Parameters:
        `in` - the input byte array.
        `inOff` - the offset into the in array where the data to be processed starts.
        `len` - the number of bytes to be processed.
        `out` - the output buffer the processed bytes go into.
        `outOff` - the offset into the output byte array the processed data starts at.
      Returns:
        the number of bytes produced - should always be len.
      Throws:
        `DataLengthException` - if the output buffer is too small.

    - #### reset

          void reset()

      reset the cipher. This leaves it in the same state it was at after the last init (if there was one).