Package org.bouncycastle.crypto.digests

Class SkeinEngine

  • All Implemented Interfaces:
    Memoable
    public class SkeinEngine
extends java.lang.Object
implements Memoable
    Implementation of the Skein family of parameterised hash functions in 256, 512 and 1024 bit block sizes, based on the Threefish tweakable block cipher.

    This is the 1.3 version of Skein defined in the Skein hash function submission to the NIST SHA-3 competition in October 2010.

    Skein was designed by Niels Ferguson - Stefan Lucks - Bruce Schneier - Doug Whiting - Mihir Bellare - Tadayoshi Kohno - Jon Callas - Jesse Walker.

    This implementation is the basis for SkeinDigest and SkeinMac, implementing the parameter based configuration system that allows Skein to be adapted to multiple applications.
    Initialising the engine with SkeinParameters allows standard and arbitrary parameters to be applied during the Skein hash function.

    Implemented:

    • 256, 512 and 1024 bit internal states.
    • Full 96 bit input length.
    • Parameters defined in the Skein specification, and arbitrary other pre and post message parameters.
    • Arbitrary output size in 1 byte intervals.

    Not implemented:

    • Sub-byte length input (bit padding).
    • Tree hashing.
    See Also:
    SkeinParameters

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static class  SkeinEngine.Parameter  

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static int SKEIN_1024
      1024 bit block size - Skein 1024
      static int SKEIN_256
      256 bit block size - Skein 256
      static int SKEIN_512
      512 bit block size - Skein 512

    • Constructor Summary

      Constructors 
      Constructor Description
      SkeinEngine​(int blockSizeBits, int outputSizeBits)
      Constructs a Skein engine.
      SkeinEngine​(SkeinEngine engine)
      Creates a SkeinEngine as an exact copy of an existing instance.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      Memoable copy()
      Produce a copy of this object with its configuration and in its current state.
      int doFinal​(byte[] out, int outOff)  
      int getBlockSize()  
      int getOutputSize()  
      void init​(SkeinParameters params)
      Initialises the Skein engine with the provided parameters.
      void reset()
      Reset the engine to the initial state (with the key and any pre-message parameters , ready to accept message input.
      void reset​(Memoable other)
      Restore a copied object state into this object.
      void update​(byte in)  
      void update​(byte[] in, int inOff, int len)  

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • SKEIN_256

        public static final int SKEIN_256
        256 bit block size - Skein 256
        See Also:
        Constant Field Values

      • SKEIN_512

        public static final int SKEIN_512
        512 bit block size - Skein 512
        See Also:
        Constant Field Values

      • SKEIN_1024

        public static final int SKEIN_1024
        1024 bit block size - Skein 1024
        See Also:
        Constant Field Values

    • Constructor Detail

      • SkeinEngine

        public SkeinEngine​(int blockSizeBits,
                   int outputSizeBits)
        Constructs a Skein engine.
        Parameters:
        blockSizeBits - the internal state size in bits - one of SKEIN_256, SKEIN_512 or SKEIN_1024.
        outputSizeBits - the output/digest size to produce in bits, which must be an integral number of bytes.

      • SkeinEngine

        public SkeinEngine​(SkeinEngine engine)
        Creates a SkeinEngine as an exact copy of an existing instance.

    • Method Detail

      • copy

        public Memoable copy()
        Description copied from interface: Memoable
        Produce a copy of this object with its configuration and in its current state.

        The returned object may be used simply to store the state, or may be used as a similar object starting from the copied state.

        Specified by:
        copy in interface Memoable

      • reset

        public void reset​(Memoable other)
        Description copied from interface: Memoable
        Restore a copied object state into this object.

        Implementations of this method should try to avoid or minimise memory allocation to perform the reset.

        Specified by:
        reset in interface Memoable
        Parameters:
        other - an object originally copied from an object of the same type as this instance.

      • getOutputSize

        public int getOutputSize()

      • getBlockSize

        public int getBlockSize()

      • init

        public void init​(SkeinParameters params)
        Initialises the Skein engine with the provided parameters. See SkeinParameters for details on the parameterisation of the Skein hash function.
        Parameters:
        params - the parameters to apply to this engine, or null to use no parameters.

      • reset

        public void reset()
        Reset the engine to the initial state (with the key and any pre-message parameters , ready to accept message input.

      • update

        public void update​(byte in)

      • update

        public void update​(byte[] in,
                   int inOff,
                   int len)

      • doFinal

        public int doFinal​(byte[] out,
                   int outOff)