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 javax.crypto.SecretKey;

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

interface JcaJceExtHelper
    extends JcaJceHelper
{
    JceAsymmetricKeyUnwrapper createAsymmetricUnwrapper(AlgorithmIdentifier keyEncryptionAlgorithm, PrivateKey keyEncryptionKey);

    JceKTSKeyUnwrapper createAsymmetricUnwrapper(AlgorithmIdentifier keyEncryptionAlgorithm, PrivateKey keyEncryptionKey, byte[] partyUInfo, byte[] partyVInfo);

    SymmetricKeyUnwrapper createSymmetricUnwrapper(AlgorithmIdentifier keyEncryptionAlgorithm, SecretKey keyEncryptionKey);
}