Running Microsoft Windows 2000 Professional

Digital signatures and encryption are two methods by which you can make your e-mail more secure. A digital signature assures recipients of a message that the message has not been altered since you sent it. Encryption encodes your message so that only the recipients to whom it is addressed are able to read it.

Obtaining a Digital ID

Digital signatures and encryption both require you to obtain and use a digital ID. A digital ID, also known as a security certificate, is a statement issued by a third-party certifying authority attesting to your identity. Your digital ID is good only for a particular e-mail account but can be transferred from computer to computer.

To get a digital ID from a certifying authority, open the Security tab of the Outlook Express Options dialog box and click the Get Digital ID button. A Web page will open that lets you choose a digital ID. Once you have obtained your digital ID, you can digitally sign individual messages, or you can configure Outlook Express so that all your outgoing messages are digitally signed. To add your digital signature to an individual message, open the Tools menu in the New Message window and choose Digitally Sign. Alternatively, click the Digitally Sign Message button on the New Message window's toolbar.

To add your digital signature to all outgoing messages:

1. Open Outlook Express's Tools menu and choose Options.
2. Click the Security tab.
3. Select the Digitally Sign All Outgoing Messages check box.

TIP

Exchanging Encrypted Messages

Outlook Express uses a public key/private key system to send and receive secure mail. To send encrypted mail to you, a correspondent must have your public key. A message sent to you is encrypted with your public key. When you receive the message, Outlook Express decodes it with your private key, which is stored on your hard disk.

When you add your digital signature to an outgoing message, you are, in effect, attaching your public key. Your private key was stored on your hard disk when you obtained your digital ID.

To enable a correspondent to send encrypted mail to you, you must first send him or her a digitally signed message. Your correspondent must then attach your public key to your address-book entry on his or her system. The procedure for doing that depends on the e-mail program that your correspondent is using. To send an encrypted message to you, your correspondent must use whatever procedure his or her e-mail program requires. On your end, Outlook Express decodes the encrypted message automatically.

To send an encrypted message to someone else, you must first obtain the recipient's public key. You do that by receiving a digitally signed message from your correspondent. When you receive the digitally signed message in Outlook Express, it will be automatically added to your Address Book and you will see a red signature icon added next to that person's name. You can also add the sender manually by right-clicking the message header in the message list and selecting Add Sender To Address Book.

To send an encrypted message to a correspondent once you have his or her public key, open the Tools menu in the New Message window and choose Encrypt. Alternatively, click Encrypt on the New Message window's toolbar.

To encrypt all outbound messages:

1. Open Outlook Express's Tools menu and choose Options.
2. Click the Security tab.
3. Select the Encrypt Contents And Attachments For All Outgoing Messages check box.

Exporting and Importing Digital IDs

Exporting a digital ID allows you to use it on a different computer. For instance, you might export the digital ID from one computer onto a floppy disk, and then carry the floppy disk to another computer and import the certificate from the floppy disk onto the computer's hard disk. To export your digital ID:

1. Open the Tools menu and choose Options.
2. Click the Security tab.
3. Click Digital IDs.
4. To export your own ID, click the Personal tab. To export someone else's, click the Other People tab.
5. Select the digital ID that you want to export.
6. Click Export and fill out the screens of the Certificate Export Wizard.

To import a digital ID:

1. Open the Tools menu and choose Options.
2. Click the Security tab.
3. Click Digital IDs.
4. Click Import and fill out the screens of the Certificate Import Wizard.