src/main/java/org/bouncycastle/jcajce/provider/digest/SHA256.java

package org.bouncycastle.jcajce.provider.digest;

import org.bouncycastle.asn1.nist.NISTObjectIdentifiers;
import org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers;
import org.bouncycastle.crypto.CipherKeyGenerator;
import org.bouncycastle.crypto.digests.SHA256Digest;
import org.bouncycastle.crypto.macs.HMac;
import org.bouncycastle.jcajce.provider.config.ConfigurableProvider;
import org.bouncycastle.jcajce.provider.symmetric.util.BaseKeyGenerator;
import org.bouncycastle.jce.provider.JCEMac;

public class SHA256
{
    static public class Digest
        extends BCMessageDigest
        implements Cloneable
    {
        public Digest()
        {
            super(new SHA256Digest());
        }

        public Object clone()
            throws CloneNotSupportedException
        {
            Digest d = (Digest)super.clone();
            d.digest = new SHA256Digest((SHA256Digest)digest);

            return d;
        }
    }

    public static class HashMac
        extends JCEMac
    {
        public HashMac()
        {
            super(new HMac(new SHA256Digest()));
        }
    }

        /**
     * HMACSHA256
     */
    public static class KeyGenerator
        extends BaseKeyGenerator
    {
        public KeyGenerator()
        {
            super("HMACSHA256", 256, new CipherKeyGenerator());
        }
    }

    public static class Mappings
        extends DigestAlgorithmProvider
    {
        private static final String PREFIX = SHA256.class.getName();

        public Mappings()
        {
        }

        public void configure(ConfigurableProvider provider)
        {
            provider.addAlgorithm("MessageDigest.SHA-256", PREFIX + "$Digest");
            provider.addAlgorithm("Alg.Alias.MessageDigest.SHA256", "SHA-256");
            provider.addAlgorithm("Alg.Alias.MessageDigest." + NISTObjectIdentifiers.id_sha256, "SHA-256");

            addHMACAlgorithm(provider, "SHA256", PREFIX + "$HashMac",  PREFIX + "$KeyGenerator");
            addHMACAlias(provider, "SHA256", PKCSObjectIdentifiers.id_hmacWithSHA256);
        }
    }
}