Encrypt file with BouncyCastle and C#

EncryptionHelper.cs

using Org.BouncyCastle.Bcpg;
using Org.BouncyCastle.Bcpg.OpenPgp;
using Org.BouncyCastle.Security;
using System;
using System.IO;

namespace Helpers
{
    public class EncryptionHelper
    {
        public static void EncryptFile(string inputFilePath, Stream outputStream, string publicKeyFilePath,
            SymmetricKeyAlgorithmTag algorithmTag = SymmetricKeyAlgorithmTag.Aes128, bool withIntegrityPacket = true, bool armor = false)
        {
            try
            {
                using (Stream publicKeyStream = File.OpenRead(publicKeyFilePath))
                {
                    PgpPublicKey encKey = ReadPublicKey(publicKeyStream);

                    using (MemoryStream bOut = new MemoryStream())
                    {
                        PgpCompressedDataGenerator comData = new PgpCompressedDataGenerator(CompressionAlgorithmTag.Zip);
                        PgpUtilities.WriteFileToLiteralData(comData.Open(bOut), PgpLiteralData.Binary, new FileInfo(inputFilePath));

                        comData.Close();
                        PgpEncryptedDataGenerator cPk = new PgpEncryptedDataGenerator(algorithmTag, withIntegrityPacket, new SecureRandom());

                        cPk.AddMethod(encKey);
                        byte[] bytes = bOut.ToArray();

                        if (armor)
                            outputStream = new ArmoredOutputStream(outputStream);

                        using (Stream cOut = cPk.Open(outputStream, bytes.Length))
                        {
                            cOut.Write(bytes, 0, bytes.Length);
                        }
                    }
                }
            }
            catch (PgpException)
            {
                throw;
            }
        }

        private static PgpPublicKey ReadPublicKey(Stream inputStream)
        {
            inputStream = PgpUtilities.GetDecoderStream(inputStream);
            PgpPublicKeyRingBundle pgpPub = new PgpPublicKeyRingBundle(inputStream);

            foreach (PgpPublicKeyRing keyRing in pgpPub.GetKeyRings())
            {
                foreach (PgpPublicKey key in keyRing.GetPublicKeys())
                {
                    if (key.IsEncryptionKey)
                    {
                        return key;
                    }
                }
            }

            throw new Exception("Can't find encryption key in key ring.");
        }
    }
}