Package org.bouncycastle.crypto.engines

Class Salsa20Engine

java.lang.Object
org.bouncycastle.crypto.engines.Salsa20Engine
All Implemented Interfaces:
SkippingCipher, SkippingStreamCipher, StreamCipher
Direct Known Subclasses:
ChaCha7539Engine, ChaChaEngine, XSalsa20Engine
public class Salsa20Engine extends Object implements SkippingStreamCipher
Implementation of Daniel J. Bernstein's Salsa20 stream cipher, Snuffle 2005

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    DEFAULT_ROUNDS
     
    protected int[]
    engineState
     
    protected int
    rounds
     
    protected static final byte[]
    sigma
    Deprecated. 
    protected static final byte[]
    tau
    Deprecated. 
    protected int[]
    x
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    Salsa20Engine()
    Creates a 20 round Salsa20 engine.
    Salsa20Engine(int rounds)
    Creates a Salsa20 engine with a specific number of rounds.

  • Method Summary

    Modifier and Type
    Method
    Description
    protected void
    advanceCounter()
     
    protected void
    advanceCounter(long diff)
     
    protected void
    generateKeyStream(byte[] output)
     
    String
    getAlgorithmName()
    Return the name of the algorithm the cipher implements.
    protected long
    getCounter()
     
    protected int
    getNonceSize()
     
    long
    getPosition()
    Return the current "position" of the cipher
    void
    init(boolean forEncryption, CipherParameters params)
    initialise a Salsa20 cipher.
    protected void
    packTauOrSigma(int keyLength, int[] state, int stateOffset)
     
    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.
    protected void
    resetCounter()
     
    protected void
    retreatCounter()
     
    protected void
    retreatCounter(long diff)
     
    byte
    returnByte(byte in)
    encrypt/decrypt a single byte returning the result.
    static void
    salsaCore(int rounds, int[] input, int[] x)
    Salsa20 function
    long
    seekTo(long position)
    Reset the cipher and then skip forward to a given position.
    protected void
    setKey(byte[] keyBytes, byte[] ivBytes)
     
    long
    skip(long numberOfBytes)
    Skip numberOfBytes forwards, or backwards.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • DEFAULT_ROUNDS

      public static final int DEFAULT_ROUNDS
      See Also:

    • sigma

      protected static final byte[] sigma
      Deprecated.

    • tau

      protected static final byte[] tau
      Deprecated.

    • rounds

      protected int rounds

    • engineState

      protected int[] engineState

    • x

      protected int[] x

  • Constructor Details

    • Salsa20Engine

      public Salsa20Engine()
      Creates a 20 round Salsa20 engine.

    • Salsa20Engine

      public Salsa20Engine(int rounds)
      Creates a Salsa20 engine with a specific number of rounds.
      Parameters:
      rounds - the number of rounds (must be an even number).

  • Method Details

    • packTauOrSigma

      protected void packTauOrSigma(int keyLength, int[] state, int stateOffset)

    • init

      public void init(boolean forEncryption, CipherParameters params)
      initialise a Salsa20 cipher.
      Specified by:
      init in interface StreamCipher
      Parameters:
      forEncryption - whether or not we are for encryption.
      params - the parameters required to set up the cipher.
      Throws:
      IllegalArgumentException - if the params argument is inappropriate.

    • getNonceSize

      protected int getNonceSize()

    • getAlgorithmName

      public 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.

    • 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.

    • advanceCounter

      protected void advanceCounter(long diff)

    • advanceCounter

      protected void advanceCounter()

    • retreatCounter

      protected void retreatCounter(long diff)

    • retreatCounter

      protected void retreatCounter()

    • processBytes

      public int processBytes(byte[] in, int inOff, int len, byte[] out, int outOff)
      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.
      Returns:
      the number of bytes produced - should always be len.

    • skip

      public long skip(long numberOfBytes)
      Description copied from interface: SkippingCipher
      Skip numberOfBytes forwards, or backwards.
      Specified by:
      skip in interface SkippingCipher
      Parameters:
      numberOfBytes - the number of bytes to skip (positive forward, negative backwards).
      Returns:
      the number of bytes actually skipped.

    • seekTo

      public long seekTo(long position)
      Description copied from interface: SkippingCipher
      Reset the cipher and then skip forward to a given position.
      Specified by:
      seekTo in interface SkippingCipher
      Parameters:
      position - the number of bytes in to set the cipher state to.
      Returns:
      the byte position moved to.

    • getPosition

      public long getPosition()
      Description copied from interface: SkippingCipher
      Return the current "position" of the cipher
      Specified by:
      getPosition in interface SkippingCipher
      Returns:
      the current byte position.

    • 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

    • getCounter

      protected long getCounter()

    • resetCounter

      protected void resetCounter()

    • setKey

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

    • generateKeyStream

      protected void generateKeyStream(byte[] output)

    • salsaCore

      public static void salsaCore(int rounds, int[] input, int[] x)
      Salsa20 function
      Parameters:
      input - input data