org.bouncycastle.cms.jcajce.JceKeyTransAuthenticatedRecipient Maven / Gradle / Ivy

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The Bouncy Castle Java APIs for CMS, PKCS, EAC, TSP, CMP, CRMF, OCSP, and certificate generation. This jar contains APIs for JDK 1.8 and up. The APIs can be used in conjunction with a JCE/JCA provider such as the one provided with the Bouncy Castle Cryptography APIs.

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package org.bouncycastle.cms.jcajce;

import java.io.OutputStream;
import java.security.Key;
import java.security.PrivateKey;

import javax.crypto.Mac;

import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.cms.CMSException;
import org.bouncycastle.cms.RecipientOperator;
import org.bouncycastle.jcajce.io.MacOutputStream;
import org.bouncycastle.operator.GenericKey;
import org.bouncycastle.operator.MacCalculator;
import org.bouncycastle.operator.jcajce.JceGenericKey;


/**
 * the KeyTransRecipientInformation class for a recipient who has been sent a secret
 * key encrypted using their public key that needs to be used to
 * extract the message.
 */
public class JceKeyTransAuthenticatedRecipient
    extends JceKeyTransRecipient
{
    public JceKeyTransAuthenticatedRecipient(PrivateKey recipientKey)
    {
        super(recipientKey);
    }

    public RecipientOperator getRecipientOperator(AlgorithmIdentifier keyEncryptionAlgorithm, final AlgorithmIdentifier contentMacAlgorithm, byte[] encryptedContentEncryptionKey)
        throws CMSException
    {
        final Key secretKey = extractSecretKey(keyEncryptionAlgorithm, contentMacAlgorithm, encryptedContentEncryptionKey);

        final Mac dataMac = contentHelper.createContentMac(secretKey, contentMacAlgorithm);

        return new RecipientOperator(new MacCalculator()
        {
            public AlgorithmIdentifier getAlgorithmIdentifier()
            {
                return contentMacAlgorithm;
            }

            public GenericKey getKey()
            {
                return new JceGenericKey(contentMacAlgorithm, secretKey);
            }

            public OutputStream getOutputStream()
            {
                return new MacOutputStream(dataMac);
            }

            public byte[] getMac()
            {
                return dataMac.doFinal();
            }
        });
    }
}