System.Security.Cryptography.TripleDESCryptoServiceProvider.CreateDecryptor C# (CSharp) Method

        public override ICryptoTransform CreateDecryptor() => _impl.CreateDecryptor();
        public override ICryptoTransform CreateDecryptor(byte[] rgbKey, byte[] rgbIV) => _impl.CreateDecryptor(rgbKey, rgbIV);

        internal static byte[] TripleDESKeyWrapDecrypt (byte[] rgbKey, byte[] rgbEncryptedWrappedKeyData) {
            // Check to see whether the length of the encrypted key is reasonable
            if (rgbEncryptedWrappedKeyData.Length != 32 && rgbEncryptedWrappedKeyData.Length != 40 
                && rgbEncryptedWrappedKeyData.Length != 48) 
                throw new CryptographicException(SecurityResources.GetResourceString("Cryptography_Xml_KW_BadKeySize"));

            TripleDESCryptoServiceProvider tripleDES = new TripleDESCryptoServiceProvider();
            // Assume no padding, use CBC mode
            tripleDES.Padding = PaddingMode.None;
            ICryptoTransform dec1 = tripleDES.CreateDecryptor(rgbKey, s_rgbTripleDES_KW_IV);
            byte[] temp2 = dec1.TransformFinalBlock(rgbEncryptedWrappedKeyData, 0, rgbEncryptedWrappedKeyData.Length);
            Array.Reverse(temp2);
            // Get the IV and temp1
            byte[] rgbIV = new byte[8];
            Buffer.BlockCopy(temp2, 0, rgbIV, 0, 8);
            byte[] temp1 = new byte[temp2.Length - rgbIV.Length];
            Buffer.BlockCopy(temp2, 8, temp1, 0, temp1.Length);

            ICryptoTransform dec2 = tripleDES.CreateDecryptor(rgbKey, rgbIV);
            byte[] rgbWKCKS = dec2.TransformFinalBlock(temp1, 0, temp1.Length);

            // checksum the key
            byte[] rgbWrappedKeyData = new byte[rgbWKCKS.Length - 8];
            Buffer.BlockCopy(rgbWKCKS, 0, rgbWrappedKeyData, 0, rgbWrappedKeyData.Length);
            SHA1CryptoServiceProvider sha = new SHA1CryptoServiceProvider();
            byte[] rgbCKS = sha.ComputeHash(rgbWrappedKeyData);
            for (int index = rgbWrappedKeyData.Length, index1 = 0; index < rgbWKCKS.Length; index++, index1++)
                if (rgbWKCKS[index] != rgbCKS[index1])
                    throw new CryptographicException(SecurityResources.GetResourceString("Cryptography_Xml_BadWrappedKeySize"));
            return rgbWrappedKeyData;
        }