org.bouncycastle.cert.crmf.jcajce.JceAsymmetricValueDecryptorGenerator.java Source code

Introduction

Here is the source code for org.bouncycastle.cert.crmf.jcajce.JceAsymmetricValueDecryptorGenerator.java

Source

package org.bouncycastle.cert.crmf.jcajce;

import java.io.InputStream;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.PrivateKey;
import java.security.Provider;
import java.security.ProviderException;
import java.security.NoSuchAlgorithmException;

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

import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.cert.crmf.CRMFException;
import org.bouncycastle.cert.crmf.ValueDecryptorGenerator;
import org.bouncycastle.jcajce.io.CipherInputStream;
import org.bouncycastle.jcajce.util.DefaultJcaJceHelper;
import org.bouncycastle.jcajce.util.NamedJcaJceHelper;
import org.bouncycastle.jcajce.util.ProviderJcaJceHelper;
import org.bouncycastle.operator.InputDecryptor;

public class JceAsymmetricValueDecryptorGenerator implements ValueDecryptorGenerator {
    private PrivateKey recipientKey;
    private CRMFHelper helper = new CRMFHelper(new DefaultJcaJceHelper());

    public JceAsymmetricValueDecryptorGenerator(PrivateKey recipientKey) {
        this.recipientKey = recipientKey;
    }

    public JceAsymmetricValueDecryptorGenerator setProvider(Provider provider) {
        this.helper = new CRMFHelper(new ProviderJcaJceHelper(provider));

        return this;
    }

    public JceAsymmetricValueDecryptorGenerator setProvider(String providerName) {
        this.helper = new CRMFHelper(new NamedJcaJceHelper(providerName));

        return this;
    }

    private Key extractSecretKey(AlgorithmIdentifier keyEncryptionAlgorithm,
            AlgorithmIdentifier contentEncryptionAlgorithm, byte[] encryptedContentEncryptionKey)
            throws CRMFException {
        try {
            Key sKey = null;

            Cipher keyCipher = helper.createCipher(keyEncryptionAlgorithm.getAlgorithm());

            try {
                keyCipher.init(Cipher.UNWRAP_MODE, recipientKey);
                sKey = keyCipher.unwrap(encryptedContentEncryptionKey,
                        contentEncryptionAlgorithm.getAlgorithm().getId(), Cipher.SECRET_KEY);
            } catch (NoSuchAlgorithmException e) {
            } catch (IllegalStateException e) {
            } catch (UnsupportedOperationException e) {
            } catch (ProviderException e) {
            }

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

            return sKey;
        } catch (InvalidKeyException e) {
            throw new CRMFException("key invalid in message.", e);
        } catch (IllegalBlockSizeException e) {
            throw new CRMFException("illegal blocksize in message.", e);
        } catch (BadPaddingException e) {
            throw new CRMFException("bad padding in message.", e);
        }
    }

    public InputDecryptor getValueDecryptor(AlgorithmIdentifier keyEncryptionAlgorithm,
            final AlgorithmIdentifier contentEncryptionAlgorithm, byte[] encryptedContentEncryptionKey)
            throws CRMFException {
        Key secretKey = extractSecretKey(keyEncryptionAlgorithm, contentEncryptionAlgorithm,
                encryptedContentEncryptionKey);

        final Cipher dataCipher = helper.createContentCipher(secretKey, contentEncryptionAlgorithm);

        return new InputDecryptor() {
            public AlgorithmIdentifier getAlgorithmIdentifier() {
                return contentEncryptionAlgorithm;
            }

            public InputStream getInputStream(InputStream dataIn) {
                return new CipherInputStream(dataIn, dataCipher);
            }
        };
    }
}