org.bouncycastle.cms.bc.BcCMSContentEncryptorBuilder 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 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.bc;

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

import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.oiw.OIWObjectIdentifiers;
import org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.cms.CMSException;
import org.bouncycastle.crypto.CipherKeyGenerator;
import org.bouncycastle.crypto.modes.AEADBlockCipher;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.crypto.util.CipherFactory;
import org.bouncycastle.operator.DefaultSecretKeySizeProvider;
import org.bouncycastle.operator.GenericKey;
import org.bouncycastle.operator.MacCaptureStream;
import org.bouncycastle.operator.OutputAEADEncryptor;
import org.bouncycastle.operator.OutputEncryptor;
import org.bouncycastle.operator.SecretKeySizeProvider;

public class BcCMSContentEncryptorBuilder
{
    private static final SecretKeySizeProvider KEY_SIZE_PROVIDER = DefaultSecretKeySizeProvider.INSTANCE;

    private final ASN1ObjectIdentifier encryptionOID;
    private final int keySize;

    private EnvelopedDataHelper helper = new EnvelopedDataHelper();
    private SecureRandom random;

    public BcCMSContentEncryptorBuilder(ASN1ObjectIdentifier encryptionOID)
    {
        this(encryptionOID, KEY_SIZE_PROVIDER.getKeySize(encryptionOID));
    }

    public BcCMSContentEncryptorBuilder(ASN1ObjectIdentifier encryptionOID, int keySize)
    {
        this.encryptionOID = encryptionOID;
        int fixedSize = KEY_SIZE_PROVIDER.getKeySize(encryptionOID);

        if (encryptionOID.equals(PKCSObjectIdentifiers.des_EDE3_CBC))
        {
            if (keySize != 168 && keySize != fixedSize)
            {
                throw new IllegalArgumentException("incorrect keySize for encryptionOID passed to builder.");
            }
            this.keySize = 168;
        }
        else if (encryptionOID.equals(OIWObjectIdentifiers.desCBC))
        {
            if (keySize != 56 && keySize != fixedSize)
            {
                throw new IllegalArgumentException("incorrect keySize for encryptionOID passed to builder.");
            }
            this.keySize = 56;
        }
        else
        {
            if (fixedSize > 0 && fixedSize != keySize)
            {
                throw new IllegalArgumentException("incorrect keySize for encryptionOID passed to builder.");
            }
            this.keySize = keySize;
        }
    }

    public BcCMSContentEncryptorBuilder setSecureRandom(SecureRandom random)
    {
        this.random = random;

        return this;
    }

    public OutputEncryptor build()
        throws CMSException
    {
        if (helper.isAuthEnveloped(encryptionOID))
        {
            return new CMSAuthOutputEncryptor(encryptionOID, keySize, random);
        }
        return new CMSOutputEncryptor(encryptionOID, keySize, random);
    }

    private class CMSOutputEncryptor
        implements OutputEncryptor
    {
        private KeyParameter encKey;
        private AlgorithmIdentifier algorithmIdentifier;
        protected Object cipher;

        CMSOutputEncryptor(ASN1ObjectIdentifier encryptionOID, int keySize, SecureRandom random)
            throws CMSException
        {
            if (random == null)
            {
                random = new SecureRandom();
            }

            CipherKeyGenerator keyGen = helper.createKeyGenerator(encryptionOID, keySize, random);

            encKey = new KeyParameter(keyGen.generateKey());

            algorithmIdentifier = helper.generateEncryptionAlgID(encryptionOID, encKey, random);

            cipher = EnvelopedDataHelper.createContentCipher(true, encKey, algorithmIdentifier);
        }

        public AlgorithmIdentifier getAlgorithmIdentifier()
        {
            return algorithmIdentifier;
        }

        public OutputStream getOutputStream(OutputStream dOut)
        {
            return CipherFactory.createOutputStream(dOut, cipher);
        }

        public GenericKey getKey()
        {
            return new GenericKey(algorithmIdentifier, encKey.getKey());
        }
    }

    private class CMSAuthOutputEncryptor
        extends CMSOutputEncryptor
        implements OutputAEADEncryptor
    {
        private AEADBlockCipher aeadCipher;
        private MacCaptureStream macOut;

        CMSAuthOutputEncryptor(ASN1ObjectIdentifier encryptionOID, int keySize, SecureRandom random)
            throws CMSException
        {
            super(encryptionOID, keySize, random);

            aeadCipher = getCipher();
        }

        private AEADBlockCipher getCipher()
        {
            if (!(cipher instanceof AEADBlockCipher))
            {
                throw new IllegalArgumentException("Unable to create Authenticated Output Encryptor without Authenticaed Data cipher!");
            }
            return (AEADBlockCipher)cipher;
        }

        public OutputStream getOutputStream(OutputStream dOut)
        {
            macOut = new MacCaptureStream(dOut, aeadCipher.getMac().length);
            return CipherFactory.createOutputStream(macOut, cipher);
        }

        public OutputStream getAADStream()
        {
            return new AADStream(aeadCipher);
        }

        public byte[] getMAC()
        {
            return macOut.getMac();
        }
    }

    private static class AADStream
        extends OutputStream
    {
        private AEADBlockCipher cipher;

        public AADStream(AEADBlockCipher cipher)
        {
            this.cipher = cipher;
        }

        public void write(byte[] buf, int off, int len)
            throws IOException
        {
            cipher.processAADBytes(buf, off, len);
        }
        
        public void write(int b)
            throws IOException
        {
            cipher.processAADByte((byte)b);
        }
    }
}