PKCS7 Encrypt using Multiple Certificates

Encrypts MIME using multiple digital certificates. Calls AddEncryptCert once per certificate, followed by a call to EncryptN. The MIME may be decrypted by any owner of one of the certificates + its associated private key.

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

bool success;
success = mime.UnlockComponent("Anything for 30-day trial.");
if (success == false) {
    textBox1.Text += mime.LastErrorText + "\r\n";
    return;
}

//  Build a simple MIME message to be encrypted:
mime.AddHeaderField("Content-Type","text/plain");
mime.AddHeaderField("abc","123");
mime.SetBody("This is a test");

//  A digital certificate is required to create PKCS7 encrypted MIME.
//  It can come from a variety of sources: .cer file, .pfx file, PEM files,
//  an in-memory representation, or directly from a Windows
//  registry-based certificate store.

//  Load one cert from a .cer file:
Chilkat.Cert cert1 = new Chilkat.Cert();
success = cert1.LoadFromFile("myCert.cer");
if (success == false) {
    textBox1.Text += cert1.LastErrorText + "\r\n";
    return;
}

//  Load another cert from the Windows registry store:
Chilkat.Cert cert2 = new Chilkat.Cert();
success = cert2.LoadByCommonName("Chilkat Sales");
if (success == false) {
    textBox1.Text += cert2.LastErrorText + "\r\n";
    return;
}

//  Tell the MIME object to use these certs for encrypting:
//  (AddEncryptCert shouldn't fail if we already know it contains
//  a valid certificate..)
success = mime.AddEncryptCert(cert1);
success = mime.AddEncryptCert(cert2);

//  Encrypt the MIME:
success = mime.EncryptN();
if (success == false) {
    textBox1.Text += mime.LastErrorText + "\r\n";
    return;
}

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

//  The resulting S/MIME looks something like this:
//  
abc: 123
Content-Disposition: attachment; filename="smime.p7m"
Content-Transfer-Encoding: base64
Content-Type: application/x-pkcs7-mime;
 name="smime.p7m"

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