Mail Safe with Digital Certificates

With the increase in e-mail usage, the threats of someone intercepting your mail have also gone up. So, how can you ensure that the

documents you are sending are not tampered with while in transit? Or, that your

messages, if intercepted, are not read by anyone other than the intended

recipient. Digital certificates offer solutions to both these problems, in the

forms of digital signatures and encrypted mail. In this article we’ll see how

you can use digital certificates to communicate securely in Outlook Express.

Once you’ve installed a digital certificate on your

machine, you’re ready to use it. To verify its usage, go to the Tools menu and

select Accounts. Select the mail account for which you have made the digital

certificate and click on Properties. Here, under the Security tab, you can

specify your certificate by clicking on Select.

This lists all the digital certificates installed on your PC.

Below this are the encryption preferences. Here, you have to select two things:

one is the certificate you want to use and the other is the algorithm to use for

encryption. The algorithms vary in bit-length ranging from 40-bit to 128-bit.

These preferences are included with your digitally-signed messages so that

others can send encrypted e-mail to you using the same settings.

Sending and receiving

digitally-signed e-mail

Once you have composed a message, go to the Tools menu and

click Digitally sign or simply click the sign icon from the toolbar. This will

show a small red ribbon next to your e-mail, which indicates that it has been

signed. The recipient of this message first gets a screen saying that the

message received has been digitally signed. Once you click Continue, you’ll be

able to see the original message contents.

Your digital certificate is now automatically added to the

recipient’s address book. This is indicated by a small red ribbon next to your

username in the recipient’s mailbox.

Sending and receiving

encrypted e-mail

After you have composed your message, you can encrypt it by

going to the Tools menu and selecting Encrypt or by clicking on the Encrypt icon

on the toolbar in Outlook Express. However, remember that before you can send an

encrypted e-mail, you need a digitally signed e-mail from your recipient because

it’ll have his public key. When you encrypt the message, Outlook Express will

use the recipient’s public key for the task. If you don’t have the person’s

digital certificate but do know the name of his Certificate Authority (CA), you

can check the CA’s Website for his certificate.

Once your mail has been encrypted, you’ll see a small blue

lock next to your recipient’s address. You can also select an option called

‘Request Secure Receipt’, which will display a message on the receipient’s

screen saying that the sender wants a receipt for his e-mail. Pressing OK will

automatically send a mail back to the sender.

When you receive an encrypted e-mail, you’ll get a message

saying that it’s encrypted and before you can read it you’ll have to enter

the password for your private key.

So even if someone gains access to your PC, the encrypted

mail you received is safe until you unlock it with a password.

Sachin Makhija