org.bouncycastle.pkcs.jcajce.JcePKCSPBEOutputEncryptorBuilder 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 1.5 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.
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package org.bouncycastle.pkcs.jcajce;

import java.io.OutputStream;
import java.security.Provider;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.CipherOutputStream;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;

import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.bc.BCObjectIdentifiers;
import org.bouncycastle.asn1.pkcs.EncryptionScheme;
import org.bouncycastle.asn1.pkcs.KeyDerivationFunc;
import org.bouncycastle.asn1.pkcs.PBES2Parameters;
import org.bouncycastle.asn1.pkcs.PBKDF2Params;
import org.bouncycastle.asn1.pkcs.PKCS12PBEParams;
import org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.jcajce.PKCS12KeyWithParameters;
import org.bouncycastle.jcajce.util.DefaultJcaJceHelper;
import org.bouncycastle.jcajce.util.JcaJceHelper;
import org.bouncycastle.jcajce.util.NamedJcaJceHelper;
import org.bouncycastle.jcajce.util.ProviderJcaJceHelper;
import org.bouncycastle.operator.DefaultSecretKeySizeProvider;
import org.bouncycastle.operator.GenericKey;
import org.bouncycastle.operator.OperatorCreationException;
import org.bouncycastle.operator.OutputEncryptor;
import org.bouncycastle.operator.SecretKeySizeProvider;

public class JcePKCSPBEOutputEncryptorBuilder
{
    private JcaJceHelper helper = new DefaultJcaJceHelper();
    private ASN1ObjectIdentifier algorithm;
    private ASN1ObjectIdentifier keyEncAlgorithm;
    private SecureRandom random;
    private SecretKeySizeProvider keySizeProvider = DefaultSecretKeySizeProvider.INSTANCE;
    private int iterationCount = 1024;

    public JcePKCSPBEOutputEncryptorBuilder(ASN1ObjectIdentifier algorithm)
    {
        if (isPKCS12(algorithm))
        {
            this.algorithm = algorithm;
            this.keyEncAlgorithm = algorithm;
        }
        else
        {
            this.algorithm = PKCSObjectIdentifiers.id_PBES2;
            this.keyEncAlgorithm = algorithm;
        }
    }

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

        return this;
    }

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

        return this;
    }

    /**
     * Set the lookup provider of AlgorithmIdentifier returning key_size_in_bits used to
     * handle PKCS5 decryption.
     *
     * @param keySizeProvider  a provider of integer secret key sizes.
     *
     * @return the current builder.
     */
    public JcePKCSPBEOutputEncryptorBuilder setKeySizeProvider(SecretKeySizeProvider keySizeProvider)
    {
        this.keySizeProvider = keySizeProvider;

        return this;
    }

    /**
     * Set the iteration count for the PBE calculation.
     *
     * @param iterationCount the iteration count to apply to the key creation.
     * @return the current builder.
     */
    public JcePKCSPBEOutputEncryptorBuilder setIterationCount(int iterationCount)
    {
        this.iterationCount = iterationCount;

        return this;
    }

    public OutputEncryptor build(final char[] password)
        throws OperatorCreationException
    {
        final Cipher cipher;
        SecretKey key;

        if (random == null)
        {
            random = new SecureRandom();
        }

        final AlgorithmIdentifier encryptionAlg;
        final byte[] salt = new byte[20];

        random.nextBytes(salt);

        try
        {
            if (isPKCS12(algorithm))
            {
                cipher = helper.createCipher(algorithm.getId());

                cipher.init(Cipher.ENCRYPT_MODE, new PKCS12KeyWithParameters(password, salt, iterationCount));

                encryptionAlg = new AlgorithmIdentifier(algorithm, new PKCS12PBEParams(salt, iterationCount));
            }
            else if (algorithm.equals(PKCSObjectIdentifiers.id_PBES2))
            {
                SecretKeyFactory keyFact = helper.createSecretKeyFactory(PKCSObjectIdentifiers.id_PBKDF2.getId());

                key = keyFact.generateSecret(new PBEKeySpec(password, salt, iterationCount, keySizeProvider.getKeySize(new AlgorithmIdentifier(keyEncAlgorithm))));

                cipher = helper.createCipher(keyEncAlgorithm.getId());

                cipher.init(Cipher.ENCRYPT_MODE, key, random);

                PBES2Parameters algParams = new PBES2Parameters(
                                   new KeyDerivationFunc(PKCSObjectIdentifiers.id_PBKDF2, new PBKDF2Params(salt, iterationCount)),
                                   new EncryptionScheme(keyEncAlgorithm, ASN1Primitive.fromByteArray(cipher.getParameters().getEncoded())));

                encryptionAlg = new AlgorithmIdentifier(algorithm, algParams);
            }
            else
            {
                throw new OperatorCreationException("unrecognised algorithm");
            }

            return new OutputEncryptor()
            {
                public AlgorithmIdentifier getAlgorithmIdentifier()
                {
                    return encryptionAlg;
                }

                public OutputStream getOutputStream(OutputStream out)
                {
                    return new CipherOutputStream(out, cipher);
                }

                public GenericKey getKey()
                {
                    if (isPKCS12(encryptionAlg.getAlgorithm()))
                    {
                        return new GenericKey(encryptionAlg, PKCS12PasswordToBytes(password));
                    }
                    else
                    {
                        return new GenericKey(encryptionAlg, PKCS5PasswordToBytes(password));
                    }
                }
            };
        }
        catch (Exception e)
        {
            throw new OperatorCreationException("unable to create OutputEncryptor: " + e.getMessage(), e);
        }
    }

    private boolean isPKCS12(ASN1ObjectIdentifier algorithm)
    {
        return algorithm.on(PKCSObjectIdentifiers.pkcs_12PbeIds)
            || algorithm.on(BCObjectIdentifiers.bc_pbe_sha1_pkcs12)
            || algorithm.on(BCObjectIdentifiers.bc_pbe_sha256_pkcs12);
    }

    /**
     * converts a password to a byte array according to the scheme in
     * PKCS5 (ascii, no padding)
     *
     * @param password a character array representing the password.
     * @return a byte array representing the password.
     */
    private static byte[] PKCS5PasswordToBytes(
        char[]  password)
    {
        if (password != null)
        {
            byte[]  bytes = new byte[password.length];

            for (int i = 0; i != bytes.length; i++)
            {
                bytes[i] = (byte)password[i];
            }

            return bytes;
        }
        else
        {
            return new byte[0];
        }
    }

    /**
     * converts a password to a byte array according to the scheme in
     * PKCS12 (unicode, big endian, 2 zero pad bytes at the end).
     *
     * @param password a character array representing the password.
     * @return a byte array representing the password.
     */
    private static byte[] PKCS12PasswordToBytes(
        char[]  password)
    {
        if (password != null && password.length > 0)
        {
                                       // +1 for extra 2 pad bytes.
            byte[]  bytes = new byte[(password.length + 1) * 2];

            for (int i = 0; i != password.length; i ++)
            {
                bytes[i * 2] = (byte)(password[i] >>> 8);
                bytes[i * 2 + 1] = (byte)password[i];
            }

            return bytes;
        }
        else
        {
            return new byte[0];
        }
    }
}