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package org.bouncycastle.cms.jcajce;

import java.security.Key;
import java.security.PrivateKey;
import java.security.Provider;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.cms.KEMRecipientInfo;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.cms.CMSException;
import org.bouncycastle.cms.KEMRecipient;
import org.bouncycastle.operator.OperatorException;

public abstract class JceKEMRecipient
    implements KEMRecipient
{
    private PrivateKey recipientKey;

    protected EnvelopedDataHelper helper = new EnvelopedDataHelper(new DefaultJcaJceExtHelper());
    protected EnvelopedDataHelper contentHelper = helper;
    protected Map extraMappings = new HashMap();
    protected boolean validateKeySize = false;
    protected boolean unwrappedKeyMustBeEncodable;

    public JceKEMRecipient(PrivateKey recipientKey)
    {
        this.recipientKey = CMSUtils.cleanPrivateKey(recipientKey);
    }

    /**
     * Set the provider to use for key recovery and content processing.
     *
     * @param provider provider to use.
     * @return this recipient.
     */
    public JceKEMRecipient setProvider(Provider provider)
    {
        this.helper = new EnvelopedDataHelper(new ProviderJcaJceExtHelper(provider));
        this.contentHelper = helper;

        return this;
    }

    /**
     * Set the provider to use for key recovery and content processing.
     *
     * @param providerName the name of the provider to use.
     * @return this recipient.
     */
    public JceKEMRecipient setProvider(String providerName)
    {
        this.helper = new EnvelopedDataHelper(new NamedJcaJceExtHelper(providerName));
        this.contentHelper = helper;

        return this;
    }

    /**
     * Internally algorithm ids are converted into cipher names using a lookup table. For some providers
     * the standard lookup table won't work. Use this method to establish a specific mapping from an
     * algorithm identifier to a specific algorithm.
     * 

* For example: *

     *     unwrapper.setAlgorithmMapping(PKCSObjectIdentifiers.rsaEncryption, "RSA");
     * 
* * @param algorithm OID of algorithm in recipient. * @param algorithmName JCE algorithm name to use. * @return the current Recipient. */ public JceKEMRecipient setAlgorithmMapping(ASN1ObjectIdentifier algorithm, String algorithmName) { extraMappings.put(algorithm, algorithmName); return this; } /** * Set the provider to use for content processing. If providerName is null a "no provider" search will be * used to satisfy getInstance calls. * * @param provider the provider to use. * @return this recipient. */ public JceKEMRecipient setContentProvider(Provider provider) { this.contentHelper = CMSUtils.createContentHelper(provider); return this; } /** * Flag that unwrapping must produce a key that will return a meaningful value from a call to Key.getEncoded(). * This is important if you are using a HSM for unwrapping and using a software based provider for * decrypting the content. Default value: false. * * @param unwrappedKeyMustBeEncodable true if getEncoded() should return key bytes, false if not necessary. * @return this recipient. */ public JceKEMRecipient setMustProduceEncodableUnwrappedKey(boolean unwrappedKeyMustBeEncodable) { this.unwrappedKeyMustBeEncodable = unwrappedKeyMustBeEncodable; return this; } /** * Set the provider to use for content processing. If providerName is null a "no provider" search will be * used to satisfy getInstance calls. * * @param providerName the name of the provider to use. * @return this recipient. */ public JceKEMRecipient setContentProvider(String providerName) { this.contentHelper = CMSUtils.createContentHelper(providerName); return this; } /** * Set validation of retrieved key sizes against the algorithm parameters for the encrypted key where possible - default is off. *

* This setting will not have any affect if the encryption algorithm in the recipient does not specify a particular key size, or * if the unwrapper is a HSM and the byte encoding of the unwrapped secret key is not available. *

* * @param doValidate true if unwrapped key's should be validated against the content encryption algorithm, false otherwise. * @return this recipient. */ public JceKEMRecipient setKeySizeValidation(boolean doValidate) { this.validateKeySize = doValidate; return this; } protected Key extractSecretKey(AlgorithmIdentifier keyEncryptionAlgorithm, AlgorithmIdentifier encryptedKeyAlgorithm, byte[] encryptedEncryptionKey) throws CMSException { // TODO: note there is a move to change the type for KEMs from KeyTrans, expect this to change KEMRecipientInfo gktParams = KEMRecipientInfo.getInstance(keyEncryptionAlgorithm.getParameters()); JceCMSKEMKeyUnwrapper unwrapper = (JceCMSKEMKeyUnwrapper)helper.createKEMUnwrapper(keyEncryptionAlgorithm, recipientKey); // TODO: .setMustProduceEncodableUnwrappedKey(unwrappedKeyMustBeEncodable); if (!extraMappings.isEmpty()) { for (Iterator it = extraMappings.keySet().iterator(); it.hasNext(); ) { ASN1ObjectIdentifier algorithm = (ASN1ObjectIdentifier)it.next(); unwrapper.setAlgorithmMapping(algorithm, (String)extraMappings.get(algorithm)); } } try { Key key = helper.getJceKey(encryptedKeyAlgorithm.getAlgorithm(), unwrapper.generateUnwrappedKey(encryptedKeyAlgorithm, encryptedEncryptionKey)); if (validateKeySize) { helper.keySizeCheck(encryptedKeyAlgorithm, key); } return key; } catch (OperatorException e) { throw new CMSException("exception unwrapping key: " + e.getMessage(), e); } } }




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