org.bouncycastle.operator.jcajce.JceAsymmetricKeyUnwrapper Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of bcpkix-fips Show documentation
The Bouncy Castle Java APIs for CMS, PKCS, EAC, TSP, CMP, CRMF, OCSP, and certificate generation. The APIs are designed primarily to be used in conjunction with the BC FIPS provider. The APIs may also be used with other providers although if being used in a FIPS context it is the responsibility of the user to ensure that any other providers used are FIPS certified.
There is a newer version: 2.0.7
Show newest version
package org.bouncycastle.operator.jcajce;

import java.security.AlgorithmParameters;
import java.security.GeneralSecurityException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.PrivateKey;
import java.security.Provider;
import java.security.ProviderException;
import java.util.HashMap;
import java.util.Map;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.spec.SecretKeySpec;

import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.jcajce.util.DefaultJcaJceHelper;
import org.bouncycastle.jcajce.util.NamedJcaJceHelper;
import org.bouncycastle.jcajce.util.ProviderJcaJceHelper;
import org.bouncycastle.operator.AsymmetricKeyUnwrapper;
import org.bouncycastle.operator.GenericKey;
import org.bouncycastle.operator.OperatorException;

public class JceAsymmetricKeyUnwrapper
    extends AsymmetricKeyUnwrapper
{
    private OperatorHelper helper = new OperatorHelper(new DefaultJcaJceHelper());
    private Map extraMappings = new HashMap();
    private PrivateKey privKey;
    private boolean unwrappedKeyMustBeEncodable;

    public JceAsymmetricKeyUnwrapper(AlgorithmIdentifier algorithmIdentifier, PrivateKey privKey)
    {
        super(algorithmIdentifier);

        this.privKey = privKey;
    }

    public JceAsymmetricKeyUnwrapper setProvider(Provider provider)
    {
        this.helper = new OperatorHelper(new ProviderJcaJceHelper(provider));

        return this;
    }

    public JceAsymmetricKeyUnwrapper setProvider(String providerName)
    {
        this.helper = new OperatorHelper(new NamedJcaJceHelper(providerName));

        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
     * with the unwrapped key. Default value: false.
     *
     * @param unwrappedKeyMustBeEncodable true if getEncoded() should return key bytes, false if not necessary.
     * @return this recipient.
     */
    public JceAsymmetricKeyUnwrapper setMustProduceEncodableUnwrappedKey(boolean unwrappedKeyMustBeEncodable)
    {
        this.unwrappedKeyMustBeEncodable = unwrappedKeyMustBeEncodable;

        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 Unwrapper.
     */
    public JceAsymmetricKeyUnwrapper setAlgorithmMapping(ASN1ObjectIdentifier algorithm, String algorithmName)
    {
        extraMappings.put(algorithm, algorithmName);

        return this;
    }

    public GenericKey generateUnwrappedKey(AlgorithmIdentifier encryptedKeyAlgorithm, byte[] encryptedKey)
        throws OperatorException
    {
        try
        {
            Key sKey = null;

            Cipher keyCipher = helper.createAsymmetricWrapper(this.getAlgorithmIdentifier().getAlgorithm(), extraMappings);
            AlgorithmParameters algParams = helper.createAlgorithmParameters(this.getAlgorithmIdentifier());

            try
            {
                if (algParams != null)
                {
                    keyCipher.init(Cipher.UNWRAP_MODE, privKey, algParams);
                }
                else
                {
                    keyCipher.init(Cipher.UNWRAP_MODE, privKey);
                }

                sKey = keyCipher.unwrap(encryptedKey, helper.getKeyAlgorithmName(encryptedKeyAlgorithm.getAlgorithm()), Cipher.SECRET_KEY);

                // check key will work with a software provider.
                if (unwrappedKeyMustBeEncodable)
                {
                    try
                    {
                        byte[] keyBytes = sKey.getEncoded();

                        if (keyBytes == null || keyBytes.length == 0)
                        {
                            sKey = null;
                        }
                    }
                    catch (Exception e)
                    {
                        sKey = null; // try doing a decrypt
                    }
                }
            }
            catch (GeneralSecurityException e)
            {   // try decrypt
            }
            catch (IllegalStateException e)
            {   // try decrypt
            }
            catch (UnsupportedOperationException e)
            {   // try decrypt
            }
            catch (ProviderException e)
            {    // try decrypt
            }

            // some providers do not support UNWRAP (this appears to be only for asymmetric algorithms)
            if (sKey == null)
            {
                keyCipher.init(Cipher.DECRYPT_MODE, privKey);
                sKey = new SecretKeySpec(keyCipher.doFinal(encryptedKey), encryptedKeyAlgorithm.getAlgorithm().getId());
            }

            return new JceGenericKey(encryptedKeyAlgorithm, sKey);
        }
        catch (InvalidKeyException e)
        {
            throw new OperatorException("key invalid: " + e.getMessage(), e);
        }
        catch (IllegalBlockSizeException e)
        {
            throw new OperatorException("illegal blocksize: " + e.getMessage(), e);
        }
        catch (BadPaddingException e)
        {
            throw new OperatorException("bad padding: " + e.getMessage(), e);
        }
    }
}