Merge pull request PHPMailer#504 from Nibbels/master

Certificate Chain fix for Thunderbird

examples/signed-mail.phps

@@ -34,6 +34,11 @@
  * openssl pkcs12 -in exported-cert.pfx -clcerts -nokeys -out cert.crt
  *
  * Again, the way you name your certificate is up to you. You will be also asked for the Import Password.
+ * To create the certificate-chain file use the following command:
+ *
+ * openssl pkcs12 -in exported-cert.pfx -cacerts -out certchain.pem
+ *
+ * Again, the way you name your chain file is up to you. You will be also asked for the Import Password.
  *
  *
  * STEP 3 - Code (most of the code is copied from the mail.phps example)
@@ -64,8 +69,9 @@ $mail->addAttachment('images/phpmailer_mini.png');
 //signing the email
 $mail->sign('/path/to/cert.crt', //the location of your certificate file
 			'/path/to/cert.key', //the location of your private key file
-		   'yourSecretPrivateKeyPassword'); //the password you protected your private key with (may be empty but parameter can not mit omitted!)
-			//!!!! This is not the Import Password !!!!
+		   'yourSecretPrivateKeyPassword', //the password you protected your private key with (may be empty but parameter can not mit omitted!)
+		   '/path/to/certchain.pem');  //the location of your chain file
+		//!!!! yourSecretPrivateKeyPassword is not the Import Password !!!!
 
 //send the message, check for errors
 if (!$mail->send()) {
@@ -79,4 +85,4 @@ if (!$mail->send()) {
  * If your email client does not support S/MIME it will most likely just show an attachment smime.p7s which is the signature contained in the email.
  * Other clients, such as Thunderbird support S/MIME natively and will validate the signature automatically and report the result in some way.
  */
-?>
+?>