Using a digital ID is a way to send secure e-mail by digitally signing messages with a certificate that proves your identity. A digital signature is similar to showing your driver's license when you cash a check. If you want to send and reply to e-mail securely, you need to get a digital ID from a certificate authority. See Digital ID on Office Marketplace to find services that issue digital IDs.
An e-mail signature, on the other hand, is just a typed personal closure to your message with your name and possibly your contact information. A digital signature and an e-mail signature are two completely different things. Remember these key points.
- A digital signature is not required to send regular e-mail.
- A digital signature is not required to reply to a digitally signed message.
- A digital signature is not required to add an e-mail signature.

I want to stop getting this message about Digital ID
This message means that Outlook Express is configures to:- Digitally sign a single message.
- Digitally sign all outgoing messages.
Choose what you want Outlook Express to do:
To stop attempting to digitally sign all outgoing messages
- Close any open messages.
- In Outlook Express, click the Tools menu, and then click Options.
- Click the Security tab.
- Clear the Digitally sign all outgoing messages check box.
To stop attempting to digitally sign a single message
- In the message, click the Sign button
so that the Digitally signed symbol is removed from the message.
I want to reply to an e-mail that has been digitally signed
You can reply to an email that has been digitally signed without having a digital signature yourself.To reply to a digitally signed message without a digital signature
- Double-click the message to open it.
- Click the Sign button
so that the Digitally signed symbol is removed from the message.
If you want to send and reply to e-mail securely, you need to get a digital ID from a certificate authority. See Digital ID on Office Marketplace to find services that issue digital IDs.
I want to add a personal e-mail signature to the end of my outgoing messages
If you want to add a signature to the end of an e-mail message you do not need a digital signature. Follow these steps.To add a signature to outgoing messages
- On the Tools menu, click Options, and then click the Signatures tab.
- To create a signature, click New and then either enter text in the Edit Signature box or click File, and then find the text or HTML file you'd like to use.
- Select the Add signatures to all outgoing messages check box.
I want to get a digital ID
A digital ID requires signing up with an independent certificate authority. To get a digital ID from a certificate authority, see Digital ID on Office Marketplace to find services that issue digital IDs.