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.cms.jcajce;

import java.security.PrivateKey;
import java.security.Provider;

import javax.crypto.SecretKey;

import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.jcajce.util.ProviderJcaJceHelper;
import org.bouncycastle.operator.SymmetricKeyUnwrapper;
import org.bouncycastle.operator.jcajce.JceAsymmetricKeyUnwrapper;
import org.bouncycastle.operator.jcajce.JceKTSKeyUnwrapper;
import org.bouncycastle.operator.jcajce.JceSymmetricKeyUnwrapper;

class ProviderJcaJceExtHelper
    extends ProviderJcaJceHelper
    implements JcaJceExtHelper
{
    public ProviderJcaJceExtHelper(Provider provider)
    {
        super(provider);
    }

    public JceAsymmetricKeyUnwrapper createAsymmetricUnwrapper(AlgorithmIdentifier keyEncryptionAlgorithm, PrivateKey keyEncryptionKey)
    {
        return new JceAsymmetricKeyUnwrapper(keyEncryptionAlgorithm, keyEncryptionKey).setProvider(provider);
    }

    public JceKTSKeyUnwrapper createAsymmetricUnwrapper(AlgorithmIdentifier keyEncryptionAlgorithm, PrivateKey keyEncryptionKey, byte[] partyUInfo, byte[] partyVInfo)
    {
        return new JceKTSKeyUnwrapper(keyEncryptionAlgorithm, keyEncryptionKey, partyUInfo, partyVInfo).setProvider(provider);
    }

    public SymmetricKeyUnwrapper createSymmetricUnwrapper(AlgorithmIdentifier keyEncryptionAlgorithm, SecretKey keyEncryptionKey)
    {
        return new JceSymmetricKeyUnwrapper(keyEncryptionAlgorithm, keyEncryptionKey).setProvider(provider);
    }
}