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 org.bouncycastle.asn1.x509.DigestInfo;

public class MessageImprint
{
    private final DigestInfo messageImprint;

    public MessageImprint(DigestInfo messageImprint)
    {
        this.messageImprint = messageImprint;
    }

    public DigestInfo toASN1Structure()
    {
        return messageImprint;
    }

    public boolean equals(Object o)
    {
        if (o == this)
        {
            return true;
        }

        if (o instanceof MessageImprint)
        {
            return messageImprint.equals(((MessageImprint)o).messageImprint);
        }

        return false;
    }

    public int hashCode()
    {
        return messageImprint.hashCode();
    }
}