using (MemoryStream outputZip = new MemoryStream())
{
    using (ZipOutputStream zipstream = new ZipOutputStream(outputZip))
    {
        zipstream.Password = req.password;
        zipstream.SetLevel(3);
        foreach (var doc in loadocs)
        {
            ZipEntry entry = new ZipEntry(doc.FileName);
            zipstream.PutNextEntry(entry);
            zipstream.Write(doc.FileData, 0, doc.FileData.Length);
        }

        zipstream.CloseEntry();
        zipstream.IsStreamOwner = false;
    }
    response.result = new Document()
    {
        name = doc1.Custodian + DateTime.Now.Date.ToString().Replace('/', '_').Replace(':', '_') + ".zip",
        content = outputZip.ToArray()
    };
}