Question

I have an application which is sending out customer statements. I have a request to digitally sign the email (with pdf attachment) from a few customer. I am using System.Net.Mail currently to send email. I can’t seem to find a clear answer, can this be accomplished in .NET or should I look into a 3rd party component?

Answer 1

Check out the Mail.dll email component:

IMail email = Mail.Text("This is message body")
  .Subject("Test")
  .From(new MailBox("mail@in_the_certificate.com", "Alice"))
  .To(new MailBox("[e-mail]", "Bob"))
  .AddAttachment(@"c:\invoice.pdf")
  .SignWith(new X509Certificate2("TestCertificate.pfx", ""))
  .Create();

using (Smtp smtp = new Smtp())
{
    smtp.Connect("smtp.server.com");
    smtp.Ehlo();
    smtp.Login("user", "password");
    smtp.SendMessage(email);
    smtp.Close();
} 

You can also use Mail.dll’s template engine to create the message body.

Disclaimer: Please note that it is a commercial product (reasonly priced though) that I helped to create.