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