S/MIME Signed Message

Create an S/MIME signed (PKCS7) message.

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Chilkat.Mime mime = new Chilkat.Mime();

bool success;
success = mime.UnlockComponent("Anything for 30-day trial.");
if (success == false) {
    MessageBox.Show(mime.LastErrorText);
    return;
}

mime.AddHeaderField("Subject","This is a test");
mime.AddHeaderField("Abc","123");

mime.SetBodyFromPlainText("This is the body");

Chilkat.Cert cert = new Chilkat.Cert();
//  Load a certificate that has already been installed (from a .pfx)
//  on the computer:
success = cert.LoadByEmailAddress("thawte@chilkatsoft.com");
if (success == false) {
    MessageBox.Show(cert.LastErrorText);
    return;
}

//  Convert to a signed message.
success = mime.ConvertToSigned(cert);
if (success == false) {
    MessageBox.Show(mime.LastErrorText);
    return;
}

//  Display the signed MIME:
textBox1.Text += mime.GetMime() + "\r\n";

textBox1.Text += "----" + "\r\n";

//  Unwrap to restore the original MIME.
success = mime.UnwrapSecurity();
if (success == false) {
    MessageBox.Show(mime.LastErrorText);
    return;
}

//  Display the restored (unsigned) MIME:
textBox1.Text += mime.GetMime() + "\r\n";