package org.bouncycastle.jcajce.provider.symmetric.util;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.InvalidParameterException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.ShortBufferException;
import javax.crypto.interfaces.PBEKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEParameterSpec;
import javax.crypto.spec.RC2ParameterSpec;
import javax.crypto.spec.RC5ParameterSpec;

import org.bouncycastle.asn1.cms.GCMParameters;
import org.bouncycastle.crypto.BlockCipher;
import org.bouncycastle.crypto.BufferedBlockCipher;
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.DataLengthException;
import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.OutputLengthException;
import org.bouncycastle.crypto.modes.AEADBlockCipher;
import org.bouncycastle.crypto.modes.CBCBlockCipher;
import org.bouncycastle.crypto.modes.CCMBlockCipher;
import org.bouncycastle.crypto.modes.CFBBlockCipher;
import org.bouncycastle.crypto.modes.CTSBlockCipher;
import org.bouncycastle.crypto.modes.EAXBlockCipher;
import org.bouncycastle.crypto.modes.GCFBBlockCipher;
import org.bouncycastle.crypto.modes.GCMBlockCipher;
import org.bouncycastle.crypto.modes.GOFBBlockCipher;
import org.bouncycastle.crypto.modes.OCBBlockCipher;
import org.bouncycastle.crypto.modes.OFBBlockCipher;
import org.bouncycastle.crypto.modes.OpenPGPCFBBlockCipher;
import org.bouncycastle.crypto.modes.PGPCFBBlockCipher;
import org.bouncycastle.crypto.modes.SICBlockCipher;
import org.bouncycastle.crypto.paddings.BlockCipherPadding;
import org.bouncycastle.crypto.paddings.ISO10126d2Padding;
import org.bouncycastle.crypto.paddings.ISO7816d4Padding;
import org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher;
import org.bouncycastle.crypto.paddings.TBCPadding;
import org.bouncycastle.crypto.paddings.X923Padding;
import org.bouncycastle.crypto.paddings.ZeroBytePadding;
import org.bouncycastle.crypto.params.AEADParameters;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.crypto.params.ParametersWithIV;
import org.bouncycastle.crypto.params.ParametersWithRandom;
import org.bouncycastle.crypto.params.ParametersWithSBox;
import org.bouncycastle.crypto.params.RC2Parameters;
import org.bouncycastle.crypto.params.RC5Parameters;
import org.bouncycastle.jcajce.PBKDF1Key;
import org.bouncycastle.jcajce.PBKDF1KeyWithParameters;
import org.bouncycastle.jcajce.PKCS12Key;
import org.bouncycastle.jcajce.PKCS12KeyWithParameters;
import org.bouncycastle.jcajce.spec.GOST28147ParameterSpec;
import org.bouncycastle.jcajce.spec.RepeatedSecretKeySpec;
import org.bouncycastle.util.Strings;

public class BaseBlockCipher
    extends BaseWrapCipher
    implements PBE
{
    private static final Class gcmSpecClass = lookup("javax.crypto.spec.GCMParameterSpec");

    //
    // specs we can handle.
    //
    private Class[]                 availableSpecs =
                                    {
                                        RC2ParameterSpec.class,
                                        RC5ParameterSpec.class,
                                        gcmSpecClass,
                                        IvParameterSpec.class,
                                        PBEParameterSpec.class,
                                        GOST28147ParameterSpec.class
                                    };

    private BlockCipher             baseEngine;
    private BlockCipherProvider     engineProvider;
    private GenericBlockCipher      cipher;
    private ParametersWithIV        ivParam;
    private AEADParameters          aeadParams;

    private int keySizeInBits;
    private int scheme = -1;
    private int digest;

    private int                     ivLength = 0;

    private boolean                 padded;
    private boolean                 fixedIv = true;
    private PBEParameterSpec        pbeSpec = null;
    private String                  pbeAlgorithm = null;

    private String                  modeName = null;

    private static Class lookup(String className)
    {
        try
        {
            Class def = BaseBlockCipher.class.getClassLoader().loadClass(className);

            return def;
        }
        catch (Exception e)
        {
            return null;
        }
    }

    protected BaseBlockCipher(
        BlockCipher engine)
    {
        baseEngine = engine;

        cipher = new BufferedGenericBlockCipher(engine);
    }

    protected BaseBlockCipher(
        BlockCipher engine,
        int scheme,
        int digest,
        int keySizeInBits,
        int ivLength)
    {
        baseEngine = engine;

        this.scheme = scheme;
        this.digest = digest;
        this.keySizeInBits = keySizeInBits;
        this.ivLength = ivLength;

        cipher = new BufferedGenericBlockCipher(engine);
    }

    protected BaseBlockCipher(
        BlockCipherProvider provider)
    {
        baseEngine = provider.get();
        engineProvider = provider;

        cipher = new BufferedGenericBlockCipher(provider.get());
    }

    protected BaseBlockCipher(
        AEADBlockCipher engine)
    {
        baseEngine = engine.getUnderlyingCipher();
        ivLength = baseEngine.getBlockSize();
        cipher = new AEADGenericBlockCipher(engine);
    }

    protected BaseBlockCipher(
        AEADBlockCipher engine,
        boolean fixedIv,
        int ivLength)
    {
        this.baseEngine = engine.getUnderlyingCipher();
        this.fixedIv = fixedIv;
        this.ivLength = ivLength;
        this.cipher = new AEADGenericBlockCipher(engine);
    }

    protected BaseBlockCipher(
        org.bouncycastle.crypto.BlockCipher engine,
        int ivLength)
    {
        baseEngine = engine;

        this.cipher = new BufferedGenericBlockCipher(engine);
        this.ivLength = ivLength / 8;
    }

    protected BaseBlockCipher(
        BufferedBlockCipher engine,
        int ivLength)
    {
        baseEngine = engine.getUnderlyingCipher();

        this.cipher = new BufferedGenericBlockCipher(engine);
        this.ivLength = ivLength / 8;
    }

    protected int engineGetBlockSize()
    {
        return baseEngine.getBlockSize();
    }

    protected byte[] engineGetIV()
    {
        if (aeadParams != null)
        {
            return aeadParams.getNonce();
        }

        return (ivParam != null) ? ivParam.getIV() : null;
    }

    protected int engineGetKeySize(
        Key     key)
    {
        return key.getEncoded().length * 8;
    }

    protected int engineGetOutputSize(
        int     inputLen)
    {
        return cipher.getOutputSize(inputLen);
    }

    protected AlgorithmParameters engineGetParameters()
    {
        if (engineParams == null)
        {
            if (pbeSpec != null)
            {
                try
                {
                    engineParams = createParametersInstance(pbeAlgorithm);
                    engineParams.init(pbeSpec);
                }
                catch (Exception e)
                {
                    return null;
                }
            }
            else if (ivParam != null)
            {
                String  name = cipher.getUnderlyingCipher().getAlgorithmName();

                if (name.indexOf('/') >= 0)
                {
                    name = name.substring(0, name.indexOf('/'));
                }

                try
                {
                    engineParams = createParametersInstance(name);
                    engineParams.init(ivParam.getIV());
                }
                catch (Exception e)
                {
                    throw new RuntimeException(e.toString());
                }
            }
            else if (aeadParams != null)
            {
                try
                {
                    engineParams = createParametersInstance("GCM");
                    engineParams.init(new GCMParameters(aeadParams.getNonce(), aeadParams.getMacSize() / 8).getEncoded());
                }
                catch (Exception e)
                {
                    throw new RuntimeException(e.toString());
                }
            }
        }

        return engineParams;
    }

    protected void engineSetMode(
        String  mode)
        throws NoSuchAlgorithmException
    {
        modeName = Strings.toUpperCase(mode);

        if (modeName.equals("ECB"))
        {
            ivLength = 0;
            cipher = new BufferedGenericBlockCipher(baseEngine);
        }
        else if (modeName.equals("CBC"))
        {
            ivLength = baseEngine.getBlockSize();
            cipher = new BufferedGenericBlockCipher(
                            new CBCBlockCipher(baseEngine));
        }
        else if (modeName.startsWith("OFB"))
        {
            ivLength = baseEngine.getBlockSize();
            if (modeName.length() != 3)
            {
                int wordSize = Integer.parseInt(modeName.substring(3));

                cipher = new BufferedGenericBlockCipher(
                                new OFBBlockCipher(baseEngine, wordSize));
            }
            else
            {
                cipher = new BufferedGenericBlockCipher(
                        new OFBBlockCipher(baseEngine, 8 * baseEngine.getBlockSize()));
            }
        }
        else if (modeName.startsWith("CFB"))
        {
            ivLength = baseEngine.getBlockSize();
            if (modeName.length() != 3)
            {
                int wordSize = Integer.parseInt(modeName.substring(3));

                cipher = new BufferedGenericBlockCipher(
                                new CFBBlockCipher(baseEngine, wordSize));
            }
            else
            {
                cipher = new BufferedGenericBlockCipher(
                        new CFBBlockCipher(baseEngine, 8 * baseEngine.getBlockSize()));
            }
        }
        else if (modeName.startsWith("PGP"))
        {
            boolean inlineIV = modeName.equalsIgnoreCase("PGPCFBwithIV");

            ivLength = baseEngine.getBlockSize();
            cipher = new BufferedGenericBlockCipher(
                new PGPCFBBlockCipher(baseEngine, inlineIV));
        }
        else if (modeName.equalsIgnoreCase("OpenPGPCFB"))
        {
            ivLength = 0;
            cipher = new BufferedGenericBlockCipher(
                new OpenPGPCFBBlockCipher(baseEngine));
        }
        else if (modeName.startsWith("SIC"))
        {
            ivLength = baseEngine.getBlockSize();
            if (ivLength < 16)
            {
                throw new IllegalArgumentException("Warning: SIC-Mode can become a twotime-pad if the blocksize of the cipher is too small. Use a cipher with a block size of at least 128 bits (e.g. AES)");
            }
            cipher = new BufferedGenericBlockCipher(new BufferedBlockCipher(
                        new SICBlockCipher(baseEngine)));
        }
        else if (modeName.startsWith("CTR"))
        {
            ivLength = baseEngine.getBlockSize();
            cipher = new BufferedGenericBlockCipher(new BufferedBlockCipher(
                        new SICBlockCipher(baseEngine)));
        }
        else if (modeName.startsWith("GOFB"))
        {
            ivLength = baseEngine.getBlockSize();
            cipher = new BufferedGenericBlockCipher(new BufferedBlockCipher(
                        new GOFBBlockCipher(baseEngine)));
        }
        else if (modeName.startsWith("GCFB"))
        {
            ivLength = baseEngine.getBlockSize();
            cipher = new BufferedGenericBlockCipher(new BufferedBlockCipher(
                        new GCFBBlockCipher(baseEngine)));
        }
        else if (modeName.startsWith("CTS"))
        {
            ivLength = baseEngine.getBlockSize();
            cipher = new BufferedGenericBlockCipher(new CTSBlockCipher(new CBCBlockCipher(baseEngine)));
        }
        else if (modeName.startsWith("CCM"))
        {
            ivLength = 13; // CCM nonce 7..13 bytes
            cipher = new AEADGenericBlockCipher(new CCMBlockCipher(baseEngine));
        }
        else if (modeName.startsWith("OCB"))
        {
            if (engineProvider != null)
            {
                /*
                 * RFC 7253 4.2. Nonce is a string of no more than 120 bits
                 */
                ivLength = 15;
                cipher = new AEADGenericBlockCipher(new OCBBlockCipher(baseEngine, engineProvider.get()));
            }
            else
            {
                throw new NoSuchAlgorithmException("can't support mode " + mode);
            }
        }
        else if (modeName.startsWith("EAX"))
        {
            ivLength = baseEngine.getBlockSize();
            cipher = new AEADGenericBlockCipher(new EAXBlockCipher(baseEngine));
        }
        else if (modeName.startsWith("GCM"))
        {
            ivLength = baseEngine.getBlockSize();
            cipher = new AEADGenericBlockCipher(new GCMBlockCipher(baseEngine));
        }
        else
        {
            throw new NoSuchAlgorithmException("can't support mode " + mode);
        }
    }

    protected void engineSetPadding(
        String  padding)
    throws NoSuchPaddingException
    {
        String  paddingName = Strings.toUpperCase(padding);

        if (paddingName.equals("NOPADDING"))
        {
            if (cipher.wrapOnNoPadding())
            {
                cipher = new BufferedGenericBlockCipher(new BufferedBlockCipher(cipher.getUnderlyingCipher()));
            }
        }
        else if (paddingName.equals("WITHCTS"))
        {
            cipher = new BufferedGenericBlockCipher(new CTSBlockCipher(cipher.getUnderlyingCipher()));
        }
        else
        {
            padded = true;

            if (isAEADModeName(modeName))
            {
                throw new NoSuchPaddingException("Only NoPadding can be used with AEAD modes.");
            }
            else if (paddingName.equals("PKCS5PADDING") || paddingName.equals("PKCS7PADDING"))
            {
                cipher = new BufferedGenericBlockCipher(cipher.getUnderlyingCipher());
            }
            else if (paddingName.equals("ZEROBYTEPADDING"))
            {
                cipher = new BufferedGenericBlockCipher(cipher.getUnderlyingCipher(), new ZeroBytePadding());
            }
            else if (paddingName.equals("ISO10126PADDING") || paddingName.equals("ISO10126-2PADDING"))
            {
                cipher = new BufferedGenericBlockCipher(cipher.getUnderlyingCipher(), new ISO10126d2Padding());
            }
            else if (paddingName.equals("X9.23PADDING") || paddingName.equals("X923PADDING"))
            {
                cipher = new BufferedGenericBlockCipher(cipher.getUnderlyingCipher(), new X923Padding());
            }
            else if (paddingName.equals("ISO7816-4PADDING") || paddingName.equals("ISO9797-1PADDING"))
            {
                cipher = new BufferedGenericBlockCipher(cipher.getUnderlyingCipher(), new ISO7816d4Padding());
            }
            else if (paddingName.equals("TBCPADDING"))
            {
                cipher = new BufferedGenericBlockCipher(cipher.getUnderlyingCipher(), new TBCPadding());
            }
            else
            {
                throw new NoSuchPaddingException("Padding " + padding + " unknown.");
            }
        }
    }

    protected void engineInit(
        int                     opmode,
        Key                     key,
        AlgorithmParameterSpec  params,
        SecureRandom            random)
        throws InvalidKeyException, InvalidAlgorithmParameterException
    {
        CipherParameters        param;

        this.pbeSpec = null;
        this.pbeAlgorithm = null;
        this.engineParams = null;
        this.aeadParams = null;

        //
        // basic key check
        //
        if (!(key instanceof SecretKey))
        {
            throw new InvalidKeyException("Key for algorithm " + key.getAlgorithm() + " not suitable for symmetric enryption.");
        }

        //
        // for RC5-64 we must have some default parameters
        //
        if (params == null && baseEngine.getAlgorithmName().startsWith("RC5-64"))
        {
            throw new InvalidAlgorithmParameterException("RC5 requires an RC5ParametersSpec to be passed in.");
        }

        //
        // a note on iv's - if ivLength is zero the IV gets ignored (we don't use it).
        //
        if (scheme == PKCS12 || key instanceof PKCS12Key)
        {
            SecretKey k;
            try
            {
                k = (SecretKey)key;
            }
            catch (Exception e)
            {
                throw new InvalidKeyException("PKCS12 requires a SecretKey/PBEKey");
            }

            if (params instanceof  PBEParameterSpec)
            {
                pbeSpec = (PBEParameterSpec)params;
            }

            if (k instanceof PBEKey && pbeSpec == null)
            {
                pbeSpec = new PBEParameterSpec(((PBEKey)k).getSalt(), ((PBEKey)k).getIterationCount());
            }

            if (pbeSpec == null && !(k instanceof PBEKey))
            {
                throw new InvalidKeyException("Algorithm requires a PBE key");
            }
            if (key instanceof BCPBEKey)
            {
                if (((BCPBEKey)key).getParam() != null)
                {
                    param = ((BCPBEKey)key).getParam();
                }
                else
                {
                    param = PBE.Util.makePBEParameters(k.getEncoded(), PKCS12, digest, keySizeInBits, ivLength * 8, pbeSpec, cipher.getAlgorithmName());
                }
            }
            else
            {
                param = PBE.Util.makePBEParameters(k.getEncoded(), PKCS12, digest, keySizeInBits, ivLength * 8, pbeSpec, cipher.getAlgorithmName());
            }
            if (param instanceof ParametersWithIV)
            {
                ivParam = (ParametersWithIV)param;
            }
        }
        else if (key instanceof PBKDF1Key)
        {
            PBKDF1Key k = (PBKDF1Key)key;

            if (params instanceof PBEParameterSpec)
            {
                pbeSpec = (PBEParameterSpec)params;
            }
            if (k instanceof PBKDF1KeyWithParameters && pbeSpec == null)
            {
                pbeSpec = new PBEParameterSpec(((PBKDF1KeyWithParameters)k).getSalt(), ((PBKDF1KeyWithParameters)k).getIterationCount());
            }

            param = PBE.Util.makePBEParameters(k.getEncoded(), PKCS5S1, digest, keySizeInBits, ivLength * 8, pbeSpec, cipher.getAlgorithmName());
            if (param instanceof ParametersWithIV)
            {
                ivParam = (ParametersWithIV)param;
            }
        }
        else if (key instanceof BCPBEKey)
        {
            BCPBEKey k = (BCPBEKey)key;

            if (k.getOID() != null)
            {
                pbeAlgorithm = k.getOID().getId();
            }
            else
            {
                pbeAlgorithm = k.getAlgorithm();
            }

            if (k.getParam() != null)
            {
                param = adjustParameters(params, k.getParam());
            }
            else if (params instanceof PBEParameterSpec)
            {
                pbeSpec = (PBEParameterSpec)params;
                param = PBE.Util.makePBEParameters(k, params, cipher.getUnderlyingCipher().getAlgorithmName());
            }
            else
            {
                throw new InvalidAlgorithmParameterException("PBE requires PBE parameters to be set.");
            }

            if (param instanceof ParametersWithIV)
            {
                ivParam = (ParametersWithIV)param;
            }
        }
        else if (key instanceof PBEKey)
        {
            PBEKey k = (PBEKey)key;
            pbeSpec = (PBEParameterSpec)params;
            if (k instanceof PKCS12KeyWithParameters && pbeSpec == null)
            {
                pbeSpec = new PBEParameterSpec(k.getSalt(), k.getIterationCount());
            }

            param = PBE.Util.makePBEParameters(k.getEncoded(), scheme, digest, keySizeInBits, ivLength * 8, pbeSpec, cipher.getAlgorithmName());
            if (param instanceof ParametersWithIV)
            {
                ivParam = (ParametersWithIV)param;
            }
        }
        else if (!(key instanceof RepeatedSecretKeySpec))
        {
            if (scheme == PKCS5S1 || scheme == PKCS5S1_UTF8 || scheme == PKCS5S2 || scheme == PKCS5S2_UTF8)
            {
                throw new InvalidKeyException("Algorithm requires a PBE key");
            }
            param = new KeyParameter(key.getEncoded());
        }
        else
        {
            param = null;
        }

        if (params instanceof IvParameterSpec)
        {
            if (ivLength != 0)
            {
                IvParameterSpec p = (IvParameterSpec)params;

                if (p.getIV().length != ivLength && !(cipher instanceof AEADGenericBlockCipher) && fixedIv)
                {
                    throw new InvalidAlgorithmParameterException("IV must be " + ivLength + " bytes long.");
                }

                if (param instanceof ParametersWithIV)
                {
                    param = new ParametersWithIV(((ParametersWithIV)param).getParameters(), p.getIV());
                }
                else
                {
                    param = new ParametersWithIV(param, p.getIV());
                }
                ivParam = (ParametersWithIV)param;
            }
            else
            {
                if (modeName != null && modeName.equals("ECB"))
                {
                    throw new InvalidAlgorithmParameterException("ECB mode does not use an IV");
                }
            }
        }
        else if (params instanceof GOST28147ParameterSpec)
        {
            GOST28147ParameterSpec    gost28147Param = (GOST28147ParameterSpec)params;

            param = new ParametersWithSBox(
                       new KeyParameter(key.getEncoded()), ((GOST28147ParameterSpec)params).getSbox());

            if (gost28147Param.getIV() != null && ivLength != 0)
            {
                if (param instanceof ParametersWithIV)
                {
                    param = new ParametersWithIV(((ParametersWithIV)param).getParameters(), gost28147Param.getIV());
                }
                else
                {
                    param = new ParametersWithIV(param, gost28147Param.getIV());
                }
                ivParam = (ParametersWithIV)param;
            }
        }
        else if (params instanceof RC2ParameterSpec)
        {
            RC2ParameterSpec    rc2Param = (RC2ParameterSpec)params;

            param = new RC2Parameters(key.getEncoded(), ((RC2ParameterSpec)params).getEffectiveKeyBits());

            if (rc2Param.getIV() != null && ivLength != 0)
            {
                if (param instanceof ParametersWithIV)
                {
                    param = new ParametersWithIV(((ParametersWithIV)param).getParameters(), rc2Param.getIV());
                }
                else
                {
                    param = new ParametersWithIV(param, rc2Param.getIV());
                }
                ivParam = (ParametersWithIV)param;
            }
        }
        else if (params instanceof RC5ParameterSpec)
        {
            RC5ParameterSpec    rc5Param = (RC5ParameterSpec)params;

            param = new RC5Parameters(key.getEncoded(), ((RC5ParameterSpec)params).getRounds());
            if (baseEngine.getAlgorithmName().startsWith("RC5"))
            {
                if (baseEngine.getAlgorithmName().equals("RC5-32"))
                {
                    if (rc5Param.getWordSize() != 32)
                    {
                        throw new InvalidAlgorithmParameterException("RC5 already set up for a word size of 32 not " + rc5Param.getWordSize() + ".");
                    }
                }
                else if (baseEngine.getAlgorithmName().equals("RC5-64"))
                {
                    if (rc5Param.getWordSize() != 64)
                    {
                        throw new InvalidAlgorithmParameterException("RC5 already set up for a word size of 64 not " + rc5Param.getWordSize() + ".");
                    }
                }
            }
            else
            {
                throw new InvalidAlgorithmParameterException("RC5 parameters passed to a cipher that is not RC5.");
            }
            if ((rc5Param.getIV() != null) && (ivLength != 0))
            {
                if (param instanceof ParametersWithIV)
                {
                    param = new ParametersWithIV(((ParametersWithIV)param).getParameters(), rc5Param.getIV());
                }
                else
                {
                    param = new ParametersWithIV(param, rc5Param.getIV());
                }
                ivParam = (ParametersWithIV)param;
            }
        }
        else if (gcmSpecClass != null && gcmSpecClass.isInstance(params))
        {
            if (!isAEADModeName(modeName) && !(cipher instanceof AEADGenericBlockCipher))
            {
                throw new InvalidAlgorithmParameterException("GCMParameterSpec can only be used with AEAD modes.");
            }

            try
            {
                Method tLen = gcmSpecClass.getDeclaredMethod("getTLen", new Class[0]);
                Method iv= gcmSpecClass.getDeclaredMethod("getIV", new Class[0]);

                KeyParameter keyParam;
                if (param instanceof ParametersWithIV)
                {
                    keyParam = (KeyParameter)((ParametersWithIV)param).getParameters();
                }
                else
                {
                    keyParam = (KeyParameter)param;
                }
                param = aeadParams = new AEADParameters(keyParam, ((Integer)tLen.invoke(params, new Object[0])).intValue(), (byte[])iv.invoke(params, new Object[0]));
            }
            catch (Exception e)
            {
                throw new InvalidAlgorithmParameterException("Cannot process GCMParameterSpec.");
            }
        }
        else if (params != null && !(params instanceof PBEParameterSpec))
        {
            throw new InvalidAlgorithmParameterException("unknown parameter type.");
        }

        if ((ivLength != 0) && !(param instanceof ParametersWithIV) && !(param instanceof AEADParameters))
        {
            SecureRandom    ivRandom = random;

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

            if ((opmode == Cipher.ENCRYPT_MODE) || (opmode == Cipher.WRAP_MODE))
            {
                byte[]  iv = new byte[ivLength];

                ivRandom.nextBytes(iv);
                param = new ParametersWithIV(param, iv);
                ivParam = (ParametersWithIV)param;
            }
            else if (cipher.getUnderlyingCipher().getAlgorithmName().indexOf("PGPCFB") < 0)
            {
                throw new InvalidAlgorithmParameterException("no IV set when one expected");
            }
        }

        if (random != null && padded)
        {
            param = new ParametersWithRandom(param, random);
        }

        try
        {
            switch (opmode)
            {
            case Cipher.ENCRYPT_MODE:
            case Cipher.WRAP_MODE:
                cipher.init(true, param);
                break;
            case Cipher.DECRYPT_MODE:
            case Cipher.UNWRAP_MODE:
                cipher.init(false, param);
                break;
            default:
                throw new InvalidParameterException("unknown opmode " + opmode + " passed");
            }
        }
        catch (final Exception e)
        {
            throw new InvalidKeyException(e.getMessage())
            {
                public Throwable getCause()
                {
                    return e;
                }
            };
        }
    }

    private CipherParameters adjustParameters(AlgorithmParameterSpec params, CipherParameters param)
    {
        CipherParameters key;

        if (param instanceof ParametersWithIV)
        {
            key = ((ParametersWithIV)param).getParameters();
            if (params instanceof IvParameterSpec)
            {
                IvParameterSpec iv = (IvParameterSpec)params;

                ivParam = new ParametersWithIV(key, iv.getIV());
                param = ivParam;
            }
            else if (params instanceof GOST28147ParameterSpec)
            {
                // need to pick up IV and SBox.
                GOST28147ParameterSpec gost28147Param = (GOST28147ParameterSpec)params;

                param = new ParametersWithSBox(param, gost28147Param.getSbox());

                if (gost28147Param.getIV() != null && ivLength != 0)
                {
                    ivParam = new ParametersWithIV(key, gost28147Param.getIV());
                    param = ivParam;
                }
            }
        }
        else
        {
            if (params instanceof IvParameterSpec)
            {
                IvParameterSpec iv = (IvParameterSpec)params;

                ivParam = new ParametersWithIV(param, iv.getIV());
                param = ivParam;
            }
            else if (params instanceof GOST28147ParameterSpec)
            {
                // need to pick up IV and SBox.
                GOST28147ParameterSpec gost28147Param = (GOST28147ParameterSpec)params;

                param = new ParametersWithSBox(param, gost28147Param.getSbox());

                if (gost28147Param.getIV() != null && ivLength != 0)
                {
                    param = new ParametersWithIV(param, gost28147Param.getIV());
                }
            }
        }
        return param;
    }

    protected void engineInit(
        int                 opmode,
        Key                 key,
        AlgorithmParameters params,
        SecureRandom        random) 
    throws InvalidKeyException, InvalidAlgorithmParameterException
    {
        AlgorithmParameterSpec  paramSpec = null;

        if (params != null)
        {
            for (int i = 0; i != availableSpecs.length; i++)
            {
                if (availableSpecs[i] == null)
                {
                    continue;
                }

                try
                {
                    paramSpec = params.getParameterSpec(availableSpecs[i]);
                    break;
                }
                catch (Exception e)
                {
                    // try again if possible
                }
            }

            if (paramSpec == null)
            {
                throw new InvalidAlgorithmParameterException("can't handle parameter " + params.toString());
            }
        }

        engineInit(opmode, key, paramSpec, random);
        
        engineParams = params;
    }

    protected void engineInit(
        int                 opmode,
        Key                 key,
        SecureRandom        random) 
        throws InvalidKeyException
    {
        try
        {
            engineInit(opmode, key, (AlgorithmParameterSpec)null, random);
        }
        catch (InvalidAlgorithmParameterException e)
        {
            throw new InvalidKeyException(e.getMessage());
        }
    }

    protected void engineUpdateAAD(byte[] input, int offset, int length)
    {
        cipher.updateAAD(input, offset, length);
    }

    protected void engineUpdateAAD(ByteBuffer bytebuffer)
    {
        int offset = bytebuffer.arrayOffset() + bytebuffer.position();
        int length = bytebuffer.limit() - bytebuffer.position();
        engineUpdateAAD(bytebuffer.array(), offset, length);
    }

    protected byte[] engineUpdate(
        byte[]  input,
        int     inputOffset,
        int     inputLen) 
    {
        int     length = cipher.getUpdateOutputSize(inputLen);

        if (length > 0)
        {
                byte[]  out = new byte[length];

                int len = cipher.processBytes(input, inputOffset, inputLen, out, 0);

                if (len == 0)
                {
                    return null;
                }
                else if (len != out.length)
                {
                    byte[]  tmp = new byte[len];

                    System.arraycopy(out, 0, tmp, 0, len);

                    return tmp;
                }

                return out;
        }

        cipher.processBytes(input, inputOffset, inputLen, null, 0);

        return null;
    }

    protected int engineUpdate(
        byte[]  input,
        int     inputOffset,
        int     inputLen,
        byte[]  output,
        int     outputOffset)
        throws ShortBufferException
    {
        if (outputOffset + cipher.getUpdateOutputSize(inputLen) > output.length)
        {
            throw new ShortBufferException("output buffer too short for input.");
        }

        try
        {
            return cipher.processBytes(input, inputOffset, inputLen, output, outputOffset);
        }
        catch (DataLengthException e)
        {
            // should never occur
            throw new IllegalStateException(e.toString());
        }
    }

    protected byte[] engineDoFinal(
        byte[]  input,
        int     inputOffset,
        int     inputLen) 
        throws IllegalBlockSizeException, BadPaddingException
    {
        int     len = 0;
        byte[]  tmp = new byte[engineGetOutputSize(inputLen)];

        if (inputLen != 0)
        {
            len = cipher.processBytes(input, inputOffset, inputLen, tmp, 0);
        }

        try
        {
            len += cipher.doFinal(tmp, len);
        }
        catch (DataLengthException e)
        {
            throw new IllegalBlockSizeException(e.getMessage());
        }

        if (len == tmp.length)
        {
            return tmp;
        }

        byte[]  out = new byte[len];

        System.arraycopy(tmp, 0, out, 0, len);

        return out;
    }

    protected int engineDoFinal(
        byte[]  input,
        int     inputOffset,
        int     inputLen,
        byte[]  output,
        int     outputOffset)
        throws IllegalBlockSizeException, BadPaddingException, ShortBufferException
    {
        int     len = 0;

        if (outputOffset + engineGetOutputSize(inputLen) > output.length)
        {
            throw new ShortBufferException("output buffer too short for input.");
        }

        try
        {
            if (inputLen != 0)
            {
                len = cipher.processBytes(input, inputOffset, inputLen, output, outputOffset);
            }

            return (len + cipher.doFinal(output, outputOffset + len));
        }
        catch (OutputLengthException e)
        {
            throw new IllegalBlockSizeException(e.getMessage());
        }
        catch (DataLengthException e)
        {
            throw new IllegalBlockSizeException(e.getMessage());
        }
    }

    private boolean isAEADModeName(
        String modeName)
    {
        return "CCM".equals(modeName) || "EAX".equals(modeName) || "GCM".equals(modeName) || "OCB".equals(modeName);
    }

    /*
     * The ciphers that inherit from us.
     */

    static private interface GenericBlockCipher
    {
        public void init(boolean forEncryption, CipherParameters params)
            throws IllegalArgumentException;

        public boolean wrapOnNoPadding();

        public String getAlgorithmName();

        public org.bouncycastle.crypto.BlockCipher getUnderlyingCipher();

        public int getOutputSize(int len);

        public int getUpdateOutputSize(int len);

        public void updateAAD(byte[] input, int offset, int length);

        public int processByte(byte in, byte[] out, int outOff)
            throws DataLengthException;

        public int processBytes(byte[] in, int inOff, int len, byte[] out, int outOff)
            throws DataLengthException;

        public int doFinal(byte[] out, int outOff)
            throws IllegalStateException,
            BadPaddingException;
    }

    private static class BufferedGenericBlockCipher
        implements GenericBlockCipher
    {
        private BufferedBlockCipher cipher;

        BufferedGenericBlockCipher(BufferedBlockCipher cipher)
        {
            this.cipher = cipher;
        }

        BufferedGenericBlockCipher(org.bouncycastle.crypto.BlockCipher cipher)
        {
            this.cipher = new PaddedBufferedBlockCipher(cipher);
        }

        BufferedGenericBlockCipher(org.bouncycastle.crypto.BlockCipher cipher, BlockCipherPadding padding)
        {
            this.cipher = new PaddedBufferedBlockCipher(cipher, padding);
        }

        public void init(boolean forEncryption, CipherParameters params)
            throws IllegalArgumentException
        {
            cipher.init(forEncryption, params);
        }

        public boolean wrapOnNoPadding()
        {
            return !(cipher instanceof CTSBlockCipher);
        }

        public String getAlgorithmName()
        {
            return cipher.getUnderlyingCipher().getAlgorithmName();
        }

        public org.bouncycastle.crypto.BlockCipher getUnderlyingCipher()
        {
            return cipher.getUnderlyingCipher();
        }

        public int getOutputSize(int len)
        {
            return cipher.getOutputSize(len);
        }

        public int getUpdateOutputSize(int len)
        {
            return cipher.getUpdateOutputSize(len);
        }

        public void updateAAD(byte[] input, int offset, int length)
        {
            throw new UnsupportedOperationException("AAD is not supported in the current mode.");
        }

        public int processByte(byte in, byte[] out, int outOff) throws DataLengthException
        {
            return cipher.processByte(in, out, outOff);
        }

        public int processBytes(byte[] in, int inOff, int len, byte[] out, int outOff) throws DataLengthException
        {
            return cipher.processBytes(in, inOff, len, out, outOff);
        }

        public int doFinal(byte[] out, int outOff) throws IllegalStateException, BadPaddingException
        {
            try
            {
                return cipher.doFinal(out, outOff);
            }
            catch (InvalidCipherTextException e)
            {
                throw new BadPaddingException(e.getMessage());
            }
        }
    }

    private static class AEADGenericBlockCipher
        implements GenericBlockCipher
    {
        private static final Constructor aeadBadTagConstructor;

        static {
            Class aeadBadTagClass = lookup("javax.crypto.AEADBadTagException");
            if (aeadBadTagClass != null)
            {
                aeadBadTagConstructor = findExceptionConstructor(aeadBadTagClass);
            }
            else
            {
                aeadBadTagConstructor = null;
            }
        }

        private static Constructor findExceptionConstructor(Class clazz)
        {
            try
            {
                return clazz.getConstructor(new Class[]{String.class});
            }
            catch (Exception e)
            {
                return null;
            }
        }

        private AEADBlockCipher cipher;

        AEADGenericBlockCipher(AEADBlockCipher cipher)
        {
            this.cipher = cipher;
        }

        public void init(boolean forEncryption, CipherParameters params)
            throws IllegalArgumentException
        {
            cipher.init(forEncryption, params);
        }

        public String getAlgorithmName()
        {
            return cipher.getUnderlyingCipher().getAlgorithmName();
        }

        public boolean wrapOnNoPadding()
        {
            return false;
        }

        public org.bouncycastle.crypto.BlockCipher getUnderlyingCipher()
        {
            return cipher.getUnderlyingCipher();
        }

        public int getOutputSize(int len)
        {
            return cipher.getOutputSize(len);
        }

        public int getUpdateOutputSize(int len)
        {
            return cipher.getUpdateOutputSize(len);
        }

        public void updateAAD(byte[] input, int offset, int length)
        {
            cipher.processAADBytes(input, offset, length);
        }

        public int processByte(byte in, byte[] out, int outOff) throws DataLengthException
        {
            return cipher.processByte(in, out, outOff);
        }

        public int processBytes(byte[] in, int inOff, int len, byte[] out, int outOff) throws DataLengthException
        {
            return cipher.processBytes(in, inOff, len, out, outOff);
        }

        public int doFinal(byte[] out, int outOff) throws IllegalStateException, BadPaddingException
        {
            try
            {
                return cipher.doFinal(out, outOff);
            }
            catch (InvalidCipherTextException e)
            {
                if (aeadBadTagConstructor != null)
                {
                    BadPaddingException aeadBadTag = null;
                    try
                    {
                        aeadBadTag = (BadPaddingException)aeadBadTagConstructor
                                .newInstance(new Object[]{e.getMessage()});
                    }
                    catch (Exception i)
                    {
                        // Shouldn't happen, but fall through to BadPaddingException
                    }
                    if (aeadBadTag != null)
                    {
                        throw aeadBadTag;
                    }
                }
                throw new BadPaddingException(e.getMessage());
            }
        }
    }
}
