public void Init(
            bool				forWrapping,
            ICipherParameters	param)
        {
            this.forWrapping = forWrapping;

            if (param is ParametersWithRandom)
            {
                ParametersWithRandom p = (ParametersWithRandom) param;

                this.rand = p.Random;
                this.param = (ParametersWithIV) p.Parameters;
            }
            else
            {
                if (forWrapping)
                {
                    rand = new SecureRandom();
                }

                this.param = (ParametersWithIV) param;
            }
        }
        public static ICipherParameters GenerateCipherParameters(
            string          algorithm,
            char[]          password,
            bool			wrongPkcs12Zero,
            Asn1Encodable   pbeParameters)
        {
            string mechanism = (string)algorithms[Platform.ToUpperInvariant(algorithm)];

            byte[] keyBytes = null;
            byte[] salt = null;
            int iterationCount = 0;

            if (IsPkcs12(mechanism))
            {
                Pkcs12PbeParams pbeParams = Pkcs12PbeParams.GetInstance(pbeParameters);
                salt = pbeParams.GetIV();
                iterationCount = pbeParams.Iterations.IntValue;
                keyBytes = PbeParametersGenerator.Pkcs12PasswordToBytes(password, wrongPkcs12Zero);
            }
            else if (IsPkcs5Scheme2(mechanism))
            {
                // See below
            }
            else
            {
                PbeParameter pbeParams = PbeParameter.GetInstance(pbeParameters);
                salt = pbeParams.GetSalt();
                iterationCount = pbeParams.IterationCount.IntValue;
                keyBytes = PbeParametersGenerator.Pkcs5PasswordToBytes(password);
            }

            ICipherParameters parameters = null;

            if (IsPkcs5Scheme2(mechanism))
            {
                PbeS2Parameters s2p = PbeS2Parameters.GetInstance(pbeParameters.ToAsn1Object());
                AlgorithmIdentifier encScheme = s2p.EncryptionScheme;
                DerObjectIdentifier encOid = encScheme.ObjectID;
                Asn1Object encParams = encScheme.Parameters.ToAsn1Object();

                // TODO What about s2p.KeyDerivationFunc.ObjectID?
                Pbkdf2Params pbeParams = Pbkdf2Params.GetInstance(s2p.KeyDerivationFunc.Parameters.ToAsn1Object());

                byte[] iv;
                if (encOid.Equals(PkcsObjectIdentifiers.RC2Cbc)) // PKCS5.B.2.3
                {
                    RC2CbcParameter rc2Params = RC2CbcParameter.GetInstance(encParams);
                    iv = rc2Params.GetIV();
                }
                else
                {
                    iv = Asn1OctetString.GetInstance(encParams).GetOctets();
                }

                salt = pbeParams.GetSalt();
                iterationCount = pbeParams.IterationCount.IntValue;
                keyBytes = PbeParametersGenerator.Pkcs5PasswordToBytes(password);

                int keyLength = pbeParams.KeyLength != null
                    ?	pbeParams.KeyLength.IntValue * 8
                    :	GeneratorUtilities.GetDefaultKeySize(encOid);

                PbeParametersGenerator gen = MakePbeGenerator(
                    (string)algorithmType[mechanism], null, keyBytes, salt, iterationCount);

                parameters = gen.GenerateDerivedParameters(encOid.Id, keyLength);

                if (iv != null)
                {
                    // FIXME? OpenSSL weirdness with IV of zeros (for ECB keys?)
                    if (Arrays.AreEqual(iv, new byte[iv.Length]))
                    {
                        //Console.Error.Write("***** IV all 0 (length " + iv.Length + ") *****");
                    }
                    else
                    {
                        parameters = new ParametersWithIV(parameters, iv);
                    }
                }
            }
            else if (mechanism.StartsWith("PBEwithSHA-1"))
            {
                PbeParametersGenerator generator = MakePbeGenerator(
                    (string) algorithmType[mechanism], new Sha1Digest(), keyBytes, salt, iterationCount);

                if (mechanism.Equals("PBEwithSHA-1and128bitAES-CBC-BC"))
                {
                    parameters = generator.GenerateDerivedParameters("AES", 128, 128);
                }
                else if (mechanism.Equals("PBEwithSHA-1and192bitAES-CBC-BC"))
                {
                    parameters = generator.GenerateDerivedParameters("AES", 192, 128);
                }
                else if (mechanism.Equals("PBEwithSHA-1and256bitAES-CBC-BC"))
                {
                    parameters = generator.GenerateDerivedParameters("AES", 256, 128);
                }
                else if (mechanism.Equals("PBEwithSHA-1and128bitRC4"))
                {
                    parameters = generator.GenerateDerivedParameters("RC4", 128);
                }
                else if (mechanism.Equals("PBEwithSHA-1and40bitRC4"))
                {
                    parameters = generator.GenerateDerivedParameters("RC4", 40);
                }
                else if (mechanism.Equals("PBEwithSHA-1and3-keyDESEDE-CBC"))
                {
                    parameters = generator.GenerateDerivedParameters("DESEDE", 192, 64);
                }
                else if (mechanism.Equals("PBEwithSHA-1and2-keyDESEDE-CBC"))
                {
                    parameters = generator.GenerateDerivedParameters("DESEDE", 128, 64);
                }
                else if (mechanism.Equals("PBEwithSHA-1and128bitRC2-CBC"))
                {
                    parameters = generator.GenerateDerivedParameters("RC2", 128, 64);
                }
                else if (mechanism.Equals("PBEwithSHA-1and40bitRC2-CBC"))
                {
                    parameters = generator.GenerateDerivedParameters("RC2", 40, 64);
                }
                else if (mechanism.Equals("PBEwithSHA-1andDES-CBC"))
                {
                    parameters = generator.GenerateDerivedParameters("DES", 64, 64);
                }
                else if (mechanism.Equals("PBEwithSHA-1andRC2-CBC"))
                {
                    parameters = generator.GenerateDerivedParameters("RC2", 64, 64);
                }
            }
            else if (mechanism.StartsWith("PBEwithSHA-256"))
            {
                PbeParametersGenerator generator = MakePbeGenerator(
                    (string) algorithmType[mechanism], new Sha256Digest(), keyBytes, salt, iterationCount);

                if (mechanism.Equals("PBEwithSHA-256and128bitAES-CBC-BC"))
                {
                    parameters = generator.GenerateDerivedParameters("AES", 128, 128);
                }
                else if (mechanism.Equals("PBEwithSHA-256and192bitAES-CBC-BC"))
                {
                    parameters = generator.GenerateDerivedParameters("AES", 192, 128);
                }
                else if (mechanism.Equals("PBEwithSHA-256and256bitAES-CBC-BC"))
                {
                    parameters = generator.GenerateDerivedParameters("AES", 256, 128);
                }
            }
            else if (mechanism.StartsWith("PBEwithMD5"))
            {
                PbeParametersGenerator generator = MakePbeGenerator(
                    (string)algorithmType[mechanism], new MD5Digest(), keyBytes, salt, iterationCount);

                if (mechanism.Equals("PBEwithMD5andDES-CBC"))
                {
                    parameters = generator.GenerateDerivedParameters("DES", 64, 64);
                }
                else if (mechanism.Equals("PBEwithMD5andRC2-CBC"))
                {
                    parameters = generator.GenerateDerivedParameters("RC2", 64, 64);
                }
                else if (mechanism.Equals("PBEwithMD5and128bitAES-CBC-OpenSSL"))
                {
                    parameters = generator.GenerateDerivedParameters("AES", 128, 128);
                }
                else if (mechanism.Equals("PBEwithMD5and192bitAES-CBC-OpenSSL"))
                {
                    parameters = generator.GenerateDerivedParameters("AES", 192, 128);
                }
                else if (mechanism.Equals("PBEwithMD5and256bitAES-CBC-OpenSSL"))
                {
                    parameters = generator.GenerateDerivedParameters("AES", 256, 128);
                }
            }
            else if (mechanism.StartsWith("PBEwithMD2"))
            {
                PbeParametersGenerator generator = MakePbeGenerator(
                    (string)algorithmType[mechanism], new MD2Digest(), keyBytes, salt, iterationCount);
                if (mechanism.Equals("PBEwithMD2andDES-CBC"))
                {
                    parameters = generator.GenerateDerivedParameters("DES", 64, 64);
                }
                else if (mechanism.Equals("PBEwithMD2andRC2-CBC"))
                {
                    parameters = generator.GenerateDerivedParameters("RC2", 64, 64);
                }
            }
            else if (mechanism.StartsWith("PBEwithHmac"))
            {
                string digestName = mechanism.Substring("PBEwithHmac".Length);
                IDigest digest = DigestUtilities.GetDigest(digestName);

                PbeParametersGenerator generator = MakePbeGenerator(
                    (string) algorithmType[mechanism], digest, keyBytes, salt, iterationCount);

                int bitLen = digest.GetDigestSize() * 8;
                parameters = generator.GenerateDerivedMacParameters(bitLen);
            }

            Array.Clear(keyBytes, 0, keyBytes.Length);

            return FixDesParity(mechanism, parameters);
        }
        /**
        * Method init
        *
        * @param forWrapping
        * @param param
        */
        public void Init(
            bool				forWrapping,
            ICipherParameters	parameters)
        {
            this.forWrapping = forWrapping;
            this.engine = new CbcBlockCipher(new DesEdeEngine());

            SecureRandom sr;
            if (parameters is ParametersWithRandom)
            {
                ParametersWithRandom pr = (ParametersWithRandom) parameters;
                parameters = pr.Parameters;
                sr = pr.Random;
            }
            else
            {
                sr = new SecureRandom();
            }

            if (parameters is KeyParameter)
            {
                this.param = (KeyParameter) parameters;
                if (this.forWrapping)
                {
                    // Hm, we have no IV but we want to wrap ?!?
                    // well, then we have to create our own IV.
                    this.iv = new byte[8];
                    sr.NextBytes(iv);

                    this.paramPlusIV = new ParametersWithIV(this.param, this.iv);
                }
            }
            else if (parameters is ParametersWithIV)
            {
                if (!forWrapping)
                    throw new ArgumentException("You should not supply an IV for unwrapping");

                this.paramPlusIV = (ParametersWithIV) parameters;
                this.iv = this.paramPlusIV.GetIV();
                this.param = (KeyParameter) this.paramPlusIV.Parameters;

                if (this.iv.Length != 8)
                    throw new ArgumentException("IV is not 8 octets", "parameters");
            }
        }
        /**
        * Method wrap
        *
        * @param in
        * @param inOff
        * @param inLen
        * @return
        */
        public byte[] Wrap(
            byte[]	input,
            int		inOff,
            int		length)
        {
            if (!forWrapping)
            {
                throw new InvalidOperationException("Not initialized for wrapping");
            }

            byte[] keyToBeWrapped = new byte[length];
            Array.Copy(input, inOff, keyToBeWrapped, 0, length);

            // Compute the CMS Key Checksum, (section 5.6.1), call this CKS.
            byte[] CKS = CalculateCmsKeyChecksum(keyToBeWrapped);

            // Let WKCKS = WK || CKS where || is concatenation.
            byte[] WKCKS = new byte[keyToBeWrapped.Length + CKS.Length];
            Array.Copy(keyToBeWrapped, 0, WKCKS, 0, keyToBeWrapped.Length);
            Array.Copy(CKS, 0, WKCKS, keyToBeWrapped.Length, CKS.Length);

            // Encrypt WKCKS in CBC mode using KEK as the key and IV as the
            // initialization vector. Call the results TEMP1.

            int blockSize = engine.GetBlockSize();

            if (WKCKS.Length % blockSize != 0)
                throw new InvalidOperationException("Not multiple of block length");

            engine.Init(true, paramPlusIV);

            byte [] TEMP1 = new byte[WKCKS.Length];

            for (int currentBytePos = 0; currentBytePos != WKCKS.Length; currentBytePos += blockSize)
            {
                engine.ProcessBlock(WKCKS, currentBytePos, TEMP1, currentBytePos);
            }

            // Let TEMP2 = IV || TEMP1.
            byte[] TEMP2 = new byte[this.iv.Length + TEMP1.Length];
            Array.Copy(this.iv, 0, TEMP2, 0, this.iv.Length);
            Array.Copy(TEMP1, 0, TEMP2, this.iv.Length, TEMP1.Length);

            // Reverse the order of the octets in TEMP2 and call the result TEMP3.
            byte[] TEMP3 = reverse(TEMP2);

            // Encrypt TEMP3 in CBC mode using the KEK and an initialization vector
            // of 0x 4a dd a2 2c 79 e8 21 05. The resulting cipher text is the desired
            // result. It is 40 octets long if a 168 bit key is being wrapped.
            ParametersWithIV param2 = new ParametersWithIV(this.param, IV2);
            this.engine.Init(true, param2);

            for (int currentBytePos = 0; currentBytePos != TEMP3.Length; currentBytePos += blockSize)
            {
                engine.ProcessBlock(TEMP3, currentBytePos, TEMP3, currentBytePos);
            }

            return TEMP3;
        }
        /**
        * Method unwrap
        *
        * @param in
        * @param inOff
        * @param inLen
        * @return
        * @throws InvalidCipherTextException
        */
        public byte[] Unwrap(
            byte[]	input,
            int		inOff,
            int		length)
        {
            if (forWrapping)
            {
                throw new InvalidOperationException("Not set for unwrapping");
            }
            if (input == null)
            {
                throw new InvalidCipherTextException("Null pointer as ciphertext");
            }

            int blockSize = engine.GetBlockSize();

            if (length % blockSize != 0)
            {
                throw new InvalidCipherTextException("Ciphertext not multiple of " + blockSize);
            }

            /*
            // Check if the length of the cipher text is reasonable given the key
            // type. It must be 40 bytes for a 168 bit key and either 32, 40, or
            // 48 bytes for a 128, 192, or 256 bit key. If the length is not supported
            // or inconsistent with the algorithm for which the key is intended,
            // return error.
            //
            // we do not accept 168 bit keys. it has to be 192 bit.
            int lengthA = (estimatedKeyLengthInBit / 8) + 16;
            int lengthB = estimatedKeyLengthInBit % 8;
            if ((lengthA != keyToBeUnwrapped.Length) || (lengthB != 0)) {
                throw new XMLSecurityException("empty");
            }
            */

            // Decrypt the cipher text with TRIPLedeS in CBC mode using the KEK
            // and an initialization vector (IV) of 0x4adda22c79e82105. Call the output TEMP3.
            ParametersWithIV param2 = new ParametersWithIV(this.param, IV2);
            this.engine.Init(false, param2);

            byte [] TEMP3 = new byte[length];

            for (int currentBytePos = 0; currentBytePos != TEMP3.Length; currentBytePos += blockSize)
            {
                engine.ProcessBlock(input, inOff + currentBytePos, TEMP3, currentBytePos);
            }

            // Reverse the order of the octets in TEMP3 and call the result TEMP2.
            byte[] TEMP2 = reverse(TEMP3);

            // Decompose TEMP2 into IV, the first 8 octets, and TEMP1, the remaining octets.
            this.iv = new byte[8];
            byte[] TEMP1 = new byte[TEMP2.Length - 8];
            Array.Copy(TEMP2, 0, this.iv, 0, 8);
            Array.Copy(TEMP2, 8, TEMP1, 0, TEMP2.Length - 8);

            // Decrypt TEMP1 using TRIPLedeS in CBC mode using the KEK and the IV
            // found in the previous step. Call the result WKCKS.
            this.paramPlusIV = new ParametersWithIV(this.param, this.iv);
            this.engine.Init(false, this.paramPlusIV);

            byte[] WKCKS = new byte[TEMP1.Length];

            for (int currentBytePos = 0; currentBytePos != WKCKS.Length; currentBytePos += blockSize)
            {
                engine.ProcessBlock(TEMP1, currentBytePos, WKCKS, currentBytePos);
            }

            // Decompose WKCKS. CKS is the last 8 octets and WK, the wrapped key, are
            // those octets before the CKS.
            byte[] result = new byte[WKCKS.Length - 8];
            byte[] CKStoBeVerified = new byte[8];
            Array.Copy(WKCKS, 0, result, 0, WKCKS.Length - 8);
            Array.Copy(WKCKS, WKCKS.Length - 8, CKStoBeVerified, 0, 8);

            // Calculate a CMS Key Checksum, (section 5.6.1), over the WK and compare
            // with the CKS extracted in the above step. If they are not equal, return error.
            if (!CheckCmsKeyChecksum(result, CKStoBeVerified)) {
                throw new InvalidCipherTextException(
                    "Checksum inside ciphertext is corrupted");
            }

            // WK is the wrapped key, now extracted for use in data decryption.
            return result;
        }
        /**
        * Method wrap
        *
        * @param in
        * @param inOff
        * @param inLen
        * @return
        */
        public byte[] Wrap(
            byte[]	input,
            int		inOff,
            int		length)
        {
            if (!forWrapping)
            {
                throw new InvalidOperationException("Not initialized for wrapping");
            }

            int len = length + 1;
            if ((len % 8) != 0)
            {
                len += 8 - (len % 8);
            }

            byte [] keyToBeWrapped = new byte[len];

            keyToBeWrapped[0] = (byte)length;
            Array.Copy(input, inOff, keyToBeWrapped, 1, length);

            byte[] pad = new byte[keyToBeWrapped.Length - length - 1];

            if (pad.Length > 0)
            {
                sr.NextBytes(pad);
                Array.Copy(pad, 0, keyToBeWrapped, length + 1, pad.Length);
            }

            // Compute the CMS Key Checksum, (section 5.6.1), call this CKS.
            byte[] CKS = CalculateCmsKeyChecksum(keyToBeWrapped);

            // Let WKCKS = WK || CKS where || is concatenation.
            byte[] WKCKS = new byte[keyToBeWrapped.Length + CKS.Length];

            Array.Copy(keyToBeWrapped, 0, WKCKS, 0, keyToBeWrapped.Length);
            Array.Copy(CKS, 0, WKCKS, keyToBeWrapped.Length, CKS.Length);

            // Encrypt WKCKS in CBC mode using KEK as the key and IV as the
            // initialization vector. Call the results TEMP1.
            byte [] TEMP1 = new byte[WKCKS.Length];

            Array.Copy(WKCKS, 0, TEMP1, 0, WKCKS.Length);

            int noOfBlocks = WKCKS.Length / engine.GetBlockSize();
            int extraBytes = WKCKS.Length % engine.GetBlockSize();

            if (extraBytes != 0)
            {
                throw new InvalidOperationException("Not multiple of block length");
            }

            engine.Init(true, paramPlusIV);

            for (int i = 0; i < noOfBlocks; i++)
            {
                int currentBytePos = i * engine.GetBlockSize();

                engine.ProcessBlock(TEMP1, currentBytePos, TEMP1, currentBytePos);
            }

            // Left TEMP2 = IV || TEMP1.
            byte[] TEMP2 = new byte[this.iv.Length + TEMP1.Length];

            Array.Copy(this.iv, 0, TEMP2, 0, this.iv.Length);
            Array.Copy(TEMP1, 0, TEMP2, this.iv.Length, TEMP1.Length);

            // Reverse the order of the octets in TEMP2 and call the result TEMP3.
            byte[] TEMP3 = new byte[TEMP2.Length];

            for (int i = 0; i < TEMP2.Length; i++)
            {
                TEMP3[i] = TEMP2[TEMP2.Length - (i + 1)];
            }

            // Encrypt TEMP3 in CBC mode using the KEK and an initialization vector
            // of 0x 4a dd a2 2c 79 e8 21 05. The resulting cipher text is the desired
            // result. It is 40 octets long if a 168 bit key is being wrapped.
            ParametersWithIV param2 = new ParametersWithIV(this.parameters, IV2);

            this.engine.Init(true, param2);

            for (int i = 0; i < noOfBlocks + 1; i++)
            {
                int currentBytePos = i * engine.GetBlockSize();

                engine.ProcessBlock(TEMP3, currentBytePos, TEMP3, currentBytePos);
            }

            return TEMP3;
        }