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;

import java.io.IOException;

import org.bouncycastle.asn1.cms.KEKIdentifier;
import org.bouncycastle.asn1.cms.KEKRecipientInfo;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;


the RecipientInfo class for a recipient who has been sent a message
encrypted using a secret key known to the other side.

/**
 * the RecipientInfo class for a recipient who has been sent a message
 * encrypted using a secret key known to the other side.
 */
public class KEKRecipientInformation
    extends RecipientInformation
{
    private KEKRecipientInfo      info;

    KEKRecipientInformation(
        KEKRecipientInfo        info,
        AlgorithmIdentifier     messageAlgorithm,
        CMSSecureReadable       secureReadable,
        AuthAttributesProvider  additionalData)
    {
        super(info.getKeyEncryptionAlgorithm(), messageAlgorithm, secureReadable, additionalData);

        this.info = info;

        KEKIdentifier kekId = info.getKekid();

        this.rid = new KEKRecipientId(kekId.getKeyIdentifier().getOctets());
    }

    protected RecipientOperator getRecipientOperator(Recipient recipient)
        throws CMSException, IOException
    {
        return ((KEKRecipient)recipient).getRecipientOperator(keyEncAlg, messageAlgorithm, info.getEncryptedKey().getOctets());
    }
}