Class SipHash

java.lang.Object
org.bouncycastle.crypto.macs.SipHash
All Implemented Interfaces:
Mac
Direct Known Subclasses:
SipHash128

public class SipHash extends Object implements Mac
Implementation of SipHash as specified in "SipHash: a fast short-input PRF", by Jean-Philippe Aumasson and Daniel J. Bernstein (https://131002.net/siphash/siphash.pdf).

"SipHash is a family of PRFs SipHash-c-d where the integer parameters c and d are the number of compression rounds and the number of finalization rounds. A compression round is identical to a finalization round and this round function is called SipRound. Given a 128-bit key k and a (possibly empty) byte string m, SipHash-c-d returns a 64-bit value..."

  • Field Summary Link icon

    Fields
    Modifier and Type
    Field
    Description
    protected final int
     
    protected final int
     
    protected long
     
    protected long
     
    protected long
     
    protected long
     
    protected long
     
    protected long
     
    protected long
     
    protected int
     
    protected int
     
  • Constructor Summary Link icon

    Constructors
    Constructor
    Description
    SipHash-2-4
    SipHash(int c, int d)
    SipHash-c-d
  • Method Summary Link icon

    Modifier and Type
    Method
    Description
    protected void
     
    long
     
    int
    doFinal(byte[] out, int outOff)
    Compute the final stage of the MAC writing the output to the out parameter.
    Return the name of the algorithm the MAC implements.
    int
    Return the block size for this MAC (in bytes).
    void
    Initialise the MAC.
    protected void
     
    void
    Reset the MAC.
    protected static long
    rotateLeft(long x, int n)
     
    void
    update(byte input)
    add a single byte to the mac for processing.
    void
    update(byte[] input, int offset, int length)
     

    Methods inherited from class java.lang.Object Link icon

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details Link icon

    • c Link icon

      protected final int c
    • d Link icon

      protected final int d
    • k0 Link icon

      protected long k0
    • k1 Link icon

      protected long k1
    • v0 Link icon

      protected long v0
    • v1 Link icon

      protected long v1
    • v2 Link icon

      protected long v2
    • v3 Link icon

      protected long v3
    • m Link icon

      protected long m
    • wordPos Link icon

      protected int wordPos
    • wordCount Link icon

      protected int wordCount
  • Constructor Details Link icon

    • SipHash Link icon

      public SipHash()
      SipHash-2-4
    • SipHash Link icon

      public SipHash(int c, int d)
      SipHash-c-d
      Parameters:
      c - the number of compression rounds
      d - the number of finalization rounds
  • Method Details Link icon

    • getAlgorithmName Link icon

      public String getAlgorithmName()
      Description copied from interface: Mac
      Return the name of the algorithm the MAC implements.
      Specified by:
      getAlgorithmName in interface Mac
      Returns:
      the name of the algorithm the MAC implements.
    • getMacSize Link icon

      public int getMacSize()
      Description copied from interface: Mac
      Return the block size for this MAC (in bytes).
      Specified by:
      getMacSize in interface Mac
      Returns:
      the block size for this MAC in bytes.
    • init Link icon

      public void init(CipherParameters params) throws IllegalArgumentException
      Description copied from interface: Mac
      Initialise the MAC.
      Specified by:
      init in interface Mac
      Parameters:
      params - the key and other data required by the MAC.
      Throws:
      IllegalArgumentException - if the params argument is inappropriate.
    • update Link icon

      public void update(byte input) throws IllegalStateException
      Description copied from interface: Mac
      add a single byte to the mac for processing.
      Specified by:
      update in interface Mac
      Parameters:
      input - the byte to be processed.
      Throws:
      IllegalStateException - if the MAC is not initialised.
    • update Link icon

      public void update(byte[] input, int offset, int length) throws DataLengthException, IllegalStateException
      Specified by:
      update in interface Mac
      Parameters:
      input - the array containing the input.
      offset - the index in the array the data begins at.
      length - the length of the input starting at inOff.
      Throws:
      DataLengthException - if there isn't enough data in in.
      IllegalStateException - if the MAC is not initialised.
    • doFinal Link icon

      public long doFinal() throws DataLengthException, IllegalStateException
      Throws:
      DataLengthException
      IllegalStateException
    • doFinal Link icon

      public int doFinal(byte[] out, int outOff) throws DataLengthException, IllegalStateException
      Description copied from interface: Mac
      Compute the final stage of the MAC writing the output to the out parameter.

      doFinal leaves the MAC in the same state it was after the last init.

      Specified by:
      doFinal in interface Mac
      Parameters:
      out - the array the MAC is to be output to.
      outOff - the offset into the out buffer the output is to start at.
      Throws:
      DataLengthException - if there isn't enough space in out.
      IllegalStateException - if the MAC is not initialised.
    • reset Link icon

      public void reset()
      Description copied from interface: Mac
      Reset the MAC. At the end of resetting the MAC should be in the in the same state it was after the last init (if there was one).
      Specified by:
      reset in interface Mac
    • processMessageWord Link icon

      protected void processMessageWord()
    • applySipRounds Link icon

      protected void applySipRounds(int n)
    • rotateLeft Link icon

      protected static long rotateLeft(long x, int n)