Package org.bouncycastle.crypto.engines

Class ChaChaEngine

java.lang.Object

org.bouncycastle.crypto.engines.Salsa20Engine

org.bouncycastle.crypto.engines.ChaChaEngine

All Implemented Interfaces:

SkippingCipher, SkippingStreamCipher, StreamCipher

public class ChaChaEngine
extends Salsa20Engine

Implementation of Daniel J. Bernstein's ChaCha stream cipher.

Field Summary

Fields inherited from class org.bouncycastle.crypto.engines.Salsa20Engine

DEFAULT_ROUNDS, engineState, rounds, sigma, tau, x

Constructor Summary

Constructors

Constructor	Description
ChaChaEngine()	Creates a 20 rounds ChaCha engine.
ChaChaEngine(int rounds)	Creates a ChaCha engine with a specific number of rounds.

Method Summary

Modifier and Type	Method	Description
protected void	advanceCounter()
protected void	advanceCounter(long diff)
static void	chachaCore(int rounds, int[] input, int[] x)	ChaCha function
protected void	generateKeyStream(byte[] output)
String	getAlgorithmName()	Return the name of the algorithm the cipher implements.
protected long	getCounter()
protected void	resetCounter()
protected void	retreatCounter()
protected void	retreatCounter(long diff)
protected void	setKey(byte[] keyBytes, byte[] ivBytes)

Methods inherited from class org.bouncycastle.crypto.engines.Salsa20Engine

getNonceSize, getPosition, init, packTauOrSigma, processBytes, reset, returnByte, salsaCore, seekTo, skip

Methods inherited from class java.lang.Object

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

Constructor Details

ChaChaEngine

public ChaChaEngine()

Creates a 20 rounds ChaCha engine.

ChaChaEngine

public ChaChaEngine(int rounds)

Creates a ChaCha engine with a specific number of rounds.

Parameters:

rounds - the number of rounds (must be an even number).

Method Details

getAlgorithmName

public String getAlgorithmName()

Description copied from interface: StreamCipher

Return the name of the algorithm the cipher implements.

Specified by:

getAlgorithmName in interface StreamCipher

Overrides:

getAlgorithmName in class Salsa20Engine

Returns:

the name of the algorithm the cipher implements.

advanceCounter

protected void advanceCounter(long diff)

Overrides:

advanceCounter in class Salsa20Engine

advanceCounter

protected void advanceCounter()

Overrides:

advanceCounter in class Salsa20Engine

retreatCounter

protected void retreatCounter(long diff)

Overrides:

retreatCounter in class Salsa20Engine

retreatCounter

protected void retreatCounter()

Overrides:

retreatCounter in class Salsa20Engine

getCounter

protected long getCounter()

Overrides:

getCounter in class Salsa20Engine

resetCounter

protected void resetCounter()

Overrides:

resetCounter in class Salsa20Engine

setKey

protected void setKey(byte[] keyBytes,
 byte[] ivBytes)

Overrides:

setKey in class Salsa20Engine

generateKeyStream

protected void generateKeyStream(byte[] output)

Overrides:

generateKeyStream in class Salsa20Engine

chachaCore

public static void chachaCore(int rounds,
 int[] input,
 int[] x)

ChaCha function

Parameters:

input - input data