Class XChaCha20Engine

java.lang.Object

org.bouncycastle.crypto.engines.Salsa20Engine

org.bouncycastle.crypto.engines.ChaCha7539Engine

org.bouncycastle.crypto.engines.XChaCha20Engine

All Implemented Interfaces:

SkippingCipher, SkippingStreamCipher, StreamCipher

public class XChaCha20Engine
extends ChaCha7539Engine

Implementation of the XChaCha20 stream cipher (extended-nonce ChaCha20) as described in draft-irtf-cfrg-xchacha-03.

XChaCha20 takes a 256 bit key and a 192 bit nonce. The first 128 bits of the nonce are used together with the key in HChaCha20 to derive a 256 bit subkey; that subkey, together with the remaining 64 bits of the nonce (prefixed by four zero bytes to form a 96 bit IETF nonce), then drives a standard ChaCha20-IETF stream as defined by RFC 7539.

Field Summary

Fields inherited from class Salsa20Engine

DEFAULT_ROUNDS, engineState, rounds, sigma, tau, x

Constructor Summary

Constructors

Constructor	Description
XChaCha20Engine()

Method Summary

Modifier and Type	Method	Description
String	getAlgorithmName()	Return the name of the algorithm the cipher implements.
protected int	getNonceSize()
protected void	setKey(byte[] keyBytes, byte[] ivBytes)

Methods inherited from class ChaCha7539Engine

advanceCounter, advanceCounter, generateKeyStream, getCounter, resetCounter, retreatCounter, retreatCounter

Methods inherited from class Salsa20Engine

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

Methods inherited from class Object

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

Constructor Details

XChaCha20Engine

public XChaCha20Engine()

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 ChaCha7539Engine

Returns:

the name of the algorithm the cipher implements.

getNonceSize

protected int getNonceSize()

Overrides:

getNonceSize in class ChaCha7539Engine

setKey

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

Overrides:

setKey in class ChaCha7539Engine