XChaCha20Engine (Bouncy Castle Library 1.85 API Specification)

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 org.bouncycastle.crypto.engines.Salsa20Engine
  DEFAULT_ROUNDS, engineState, rounds, sigma, tau, x

Constructor Summary

Constructors
Constructor Description

XChaCha20Engine()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`java.lang.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 org.bouncycastle.crypto.engines.ChaCha7539Engine
advanceCounter, advanceCounter, generateKeyStream, getCounter, resetCounter, retreatCounter, retreatCounter

Methods inherited from class org.bouncycastle.crypto.engines.Salsa20Engine
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 Detail
  - XChaCha20Engine
```
public XChaCha20Engine()
```
- 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
    
    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