http://www.bouncycastle.org/java.html: The Bouncy Castle Java APIs for CMS, PKCS, EAC, TSP, CMP, CRMF, OCSP, and certificate generation. This jar contains APIs for JDK 1.5 to JDK 1.8. The APIs can be used in conjunction with a JCE/JCA provider such as the one provided with the Bouncy Castle Cryptography APIs.
  • The Legion of the Bouncy Castle Inc. 
package org.bouncycastle.dvcs;

import java.io.OutputStream;

import org.bouncycastle.asn1.x509.DigestInfo;
import org.bouncycastle.operator.DigestCalculator;

public class MessageImprintBuilder
{
    private final DigestCalculator digestCalculator;

    public MessageImprintBuilder(DigestCalculator digestCalculator)
    {
        this.digestCalculator = digestCalculator;
    }

    public MessageImprint build(byte[] message)
        throws DVCSException
    {
        try
        {
            OutputStream dOut = digestCalculator.getOutputStream();

            dOut.write(message);

            dOut.close();

            return new MessageImprint(new DigestInfo(digestCalculator.getAlgorithmIdentifier(), digestCalculator.getDigest()));
        }
        catch (Exception e)
        {
            throw new DVCSException("unable to build MessageImprint: " + e.getMessage(), e);
        }
    }
}