# HC256Engine (Bouncy Castle Library 1.45 API Specification)
Date: 2013-08-05

org.bouncycastle.crypto.engines

## Class HC256Engine

- java.lang.Object
- - org.bouncycastle.crypto.engines.HC256Engine

All Implemented Interfaces:
  StreamCipher

    public class HC256Engine
    extends java.lang.Object
    implements StreamCipher

HC-256 is a software-efficient stream cipher created by Hongjun Wu. It generates keystream from a 256-bit secret key and a 256-bit initialization vector.

http://www.ecrypt.eu.org/stream/p3ciphers/hc/hc256_p3.pdf

Its brother, HC-128, is a third phase candidate in the eStream contest. The algorithm is patent-free. No attacks are known as of today (April 2007). See http://www.ecrypt.eu.org/stream/hcp3.html

### Constructor Summary

Constructors
Constructor and Description
`HC256Engine()`

### Method Summary

Methods
`java.lang.String` `getAlgorithmName()` Return the name of the algorithm the cipher implements.
`void` `init(boolean forEncryption, CipherParameters params)` Initialise a HC-256 cipher.
`void` `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.

### Methods inherited from class java.lang.Object

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

### Constructor Detail

#### HC256Engine

    public HC256Engine()

### Method Detail

#### getAlgorithmName

    public java.lang.String getAlgorithmName()

Description copied from interface: `StreamCipher`
Return the name of the algorithm the cipher implements.

Specified by:
  `getAlgorithmName` in interface `StreamCipher`
Returns:
  the name of the algorithm the cipher implements.

#### init

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

Initialise a HC-256 cipher.

Specified by:
  `init` in interface `StreamCipher`
Parameters:
  `forEncryption` - whether or not we are for encryption. Irrelevant, as encryption and decryption are the same.
  `params` - the parameters required to set up the cipher.
Throws:
  `java.lang.IllegalArgumentException` - if the params argument is inappropriate (ie. the key is not 256 bit long).

#### processBytes

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

Description copied from interface: `StreamCipher`
process a block of bytes from in putting the result into out.

Specified by:
  `processBytes` in interface `StreamCipher`
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.
Throws:
  `DataLengthException` - if the output buffer is too small.

#### reset

    public void reset()

Description copied from interface: `StreamCipher`
reset the cipher. This leaves it in the same state it was at after the last init (if there was one).

Specified by:
  `reset` in interface `StreamCipher`

#### returnByte

    public byte returnByte(byte in)

Description copied from interface: `StreamCipher`
encrypt/decrypt a single byte returning the result.

Specified by:
  `returnByte` in interface `StreamCipher`
Parameters:
  `in` - the byte to be processed.
Returns:
  the result of processing the input byte.