Monthly Archives: December 2016

How to digitally sign your outgoing emails with Outlook ?

Would you like to prove to your contacts the authenticity of your emails ? A S/MIME signature of your messages may be a solution. It will guarantee that a message comes from you, and that its content wasn’t altered. You can do it for free – as long as it’s for a personnal use – using a Comodo free email certificate. The solution may be seducing, but there are two caveats.

First, the validation of your signature is done by your recipient email client, and most email clients just don’t support it. As a rule of thumb, consider only the outlook desktop app supports it (gmail,, default android client don’t support it, iphone can support it but it’s disabled by default). And there’s nothing you can do about it.

Second, the procedure to sign your messages may give some headaches, and it’ll be different for each email client. But at least, here is a step by step guide to digitally sign outgoing messages on Outlook.

  1. Get a mail Certificate
  2. Install your mail certificate in your local certificate store
  3. Check that your certificate is properly installed
  4. Configure Outlook to sign outgoing messages

1. Get a mail certificate

If you don’t already own a mail certificate, you can get a free one from Comodo here, or directly here.
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