Package org.bouncycastle.crypto.commitments

Class HashCommitter

  • All Implemented Interfaces:
    Committer
    public class HashCommitter
extends java.lang.Object
implements Committer
    A basic hash-committer as described in "Making Mix Nets Robust for Electronic Voting by Randomized Partial Checking", by Jakobsson, Juels, and Rivest (11th Usenix Security Symposium, 2002).

    Use this class if you can enforce fixed length for messages. If you need something more general, use the GeneralHashCommitter.

    • Constructor Summary

      Constructors 
      Constructor Description
      HashCommitter​(ExtendedDigest digest, java.security.SecureRandom random)
      Base Constructor.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      Commitment commit​(byte[] message)
      Generate a commitment for the passed in message.
      boolean isRevealed​(Commitment commitment, byte[] message)
      Return true if the passed in commitment represents a commitment to the passed in message.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • HashCommitter

        public HashCommitter​(ExtendedDigest digest,
                     java.security.SecureRandom random)
        Base Constructor. The maximum message length that can be committed to is half the length of the internal block size for the digest (ExtendedDigest.getBlockLength()).
        Parameters:
        digest - digest to use for creating commitments.
        random - source of randomness for generating secrets.

    • Method Detail

      • commit

        public Commitment commit​(byte[] message)
        Generate a commitment for the passed in message.
        Specified by:
        commit in interface Committer
        Parameters:
        message - the message to be committed to,
        Returns:
        a Commitment

      • isRevealed

        public boolean isRevealed​(Commitment commitment,
                          byte[] message)
        Return true if the passed in commitment represents a commitment to the passed in message.
        Specified by:
        isRevealed in interface Committer
        Parameters:
        commitment - a commitment previously generated.
        message - the message that was expected to have been committed to.
        Returns:
        true if commitment matches message, false otherwise.