http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8.
  • The Legion of the Bouncy Castle Inc. 
package org.bouncycastle.jcajce.provider.digest;

import java.security.MessageDigest;

import org.bouncycastle.crypto.Digest;

public class BCMessageDigest
    extends MessageDigest
{
    protected Digest  digest;

    protected BCMessageDigest(
        Digest digest)
    {
        super(digest.getAlgorithmName());

        this.digest = digest;
    }

    public void engineReset() 
    {
        digest.reset();
    }

    public void engineUpdate(
        byte    input) 
    {
        digest.update(input);
    }

    public void engineUpdate(
        byte[]  input,
        int     offset,
        int     len) 
    {
        digest.update(input, offset, len);
    }

    public byte[] engineDigest() 
    {
        byte[]  digestBytes = new byte[digest.getDigestSize()];

        digest.doFinal(digestBytes, 0);

        return digestBytes;
    }
}