Using MS Outlook Express 5 Secure Email
Who's reading your email? Imagine that the only way you could communicate with
your clients, colleagues, partners and suppliers was through the picture postcard. Would
that affect what you put down in writing? It should! Why is it then, that most
people and businesses continue to communicate sensitive and sometimes critical information
via email? Of course we all want the benefits of email: the ability to communicate
swiftly, cheaply and without regard to location or time zone. But can we afford to
bet our business or our personal fortunes on the chance that the email might be read or
forged by others.
With Secure Email, you can now do something about it. Digital Certificates used
with an email program designed to take advantage of them make it possible to digitally
sign your e-mail and to receive encrypted messages. This means that when you send
e-mail, the recipients will know without a doubt that it came from you and was not
modified by someone else in transit, and that when you get incoming mail, you will know
that only you can read it.
Setting up your Default Security Settings for Secure Email
Outlook Express 5 does not support the use of separate certificates for signing and
encryption (otherwise known as Dual Certificate support). This separation is widely
regarded to be good practice, and should be taken advantage of wherever possible
through the use of email applications such as Outlook98 that do support dual certificate
operation, together with certificates that are themselves restricted to either encryption
or signing operations.
In the recognition that Outlook Express 5 uses the same certificate for both
encryption and signing purposes, before you can use Outlook Express 5 for sending signed
email and receiving encrypted e-mail, you need to indicate which digital certificate is to
be used. To do this:
- In Outlook Express 5, from the menus, choose "Tools, Accounts"
- Select the "Mail" tab and then select the email account you wish to work with
- Click on the "Properties" button
- Select the "Security" tab - a dialogue box like the one shown will appear
- Ensure that 'Use a digital ID when sending secure messages from:
name@mail-address' is selected
- Click on the "Digital ID" button.
- This will bring up a new dialogue box
Choose the certificate you want to use with this email account, then click on the
"OK" button
Note that only the digital certificates with the same e-mail address as the e-mail address
for the account will be shown
- Click on the "OK" button in the email account properties dialogue box
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- In Outlook Express 5, select Options from the Tools menu.
- Click on the Security tab.
- Click on the "Advanced" button - the dialogue box shown will appear
- Using the drop-down list, choose the minimum encryption strength for outgoing messages
that can be sent without warning you (this is a matter of personal or corporate choice,
but a selection of 128 bits would provide a good indicator of whether you were sending
with stong security or not).
- Using the drop-down list, choose the encryption level you wish to receive, (at time of
writing, recommend 3DES where available, otherwise in order of preference: RC2-128bit,
DES, RC2-40bit)
- Check the box marked "Always encrypt to myself when sending encrypted mail"
- Check the box marked "Include my digital ID when sending signed messages"
- Checking the box marked "Encode message before signing (opaque signing)" will
mean that recipients of your signed messages will not be able to read the message until
their email program has checked your digital signature. This means that any
recipient who does not have a secure email program with S/MIME capabilities will not be
able to read your messages, even though they may not be encrypted. If you wish to
allo anyone to read your signed messages, whether S/MIME enabled or not, leave this box
clear.
- To have Outlook Express 5 automatically add a contact's digital certificate to your
address book when they send you a secure email, check the box marked "Add senders'
certificates to my address book"
- Under "Check for revoked Digital IDs", select "Only when online"
- Click on the "OK" button
- Click on the "OK" button
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Digitally Signing Your E-mail with Outlook Express 5
Digitally signing a message lets the recipient know that the message and any
attachments really came from you, and haven't been tampered with. When sending a digitally
signed message, the recipient need not be using an S/MIME-enabled e-mail package. The
recipient can still read the message-- your digital signature simply shows up as an
attachment.
This "signed" icon indicates
that a message has been signed. When a signed message is received in Outlook Express 5,
this symbol appears to the left of the e-mail header in the inbox. When the signed message
is opened, this icon is displayed in the upper right corner of the address pane.
You can sign individual messages or configure your e-mail security options to
automatically sign all of the e-mail messages you send.
Signing Individual Messages
To sign an outgoing message:
- Click on the Digitally Sign Message button in the compose message window.
Note:
Clicking again on the Digitally Sign Message button will remove your digital signature
from the message.
Automatically Signing All Outgoing Messages
To configure your e-mail preferences to sign all messages:
- In Outlook Express 5, select Options from the Tools menu.
- Click on the Security tab.
- Enable the "Digitally sign all outgoing messages" checkbox.
However, digitally signing a message does not prevent it from being intercepted and
read by someone other than the intended recipient. To ensure that only the intended
recipient can read the message, you should also encrypt the message.
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Encrypting Your E-mail
The second step to securing your e-mail is to encrypt the messages that you send.
E-mail messages are relatively easy for other people to intercept and read. The only way
you can be sure that an e-mail message is private is to encrypt it so that only the
intended recipient can read it. Encrypting messages with Outlook ’98 is as easy as
signing them.
To encrypt a message, you need to have a copy of the intended recipient's Digital
Certificate used for encryption. When you receive a signed message, you can store the
sender's Digital Certificates in your address book. You can also retrieve correspondents'
Digital Certificates from online directories. For more information about storing and
maintaining Digital Certificates in your address book, (see Managing Contacts' Digital
Certificates below).
This "encrypted" icon indicates
that a message has been encrypted. When you receive an encrypted message, Outlook Express
5 decrypts the message and displays the encrypted icon when the message is viewed and the
correct private key password is entered.
You can encrypt individual messages or configure your e-mail security options to
automatically encrypt all e-mail messages to recipients whose Digital Certificates are
stored in your address book.
Encrypting Individual Messages
To encrypt an outgoing message:
- Click on the Encrypt Message button in the message window.
Note: Clicking again on the Encrypt Message button will toggle the encryption setting. 
Automatically Encrypting Outgoing Messages
To configure your e-mail preferences to automatically encrypt outgoing messages to
recipients whose Digital Certificates are stored in your address book:
- In Outlook Express 5, select Options from the Tools menu.
- Click on the Security tab.
- Enable the "Encrypt contents and attachments for all outgoing messages"
checkbox.
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Managing Contacts’ Digital Certificates
To send an encrypted message, you must have a copy of the recipient's Digital
Certificate used for encryption in your address book. Outlook Express 5 enables you to
view Digital Certificates stored in your Address Book and easily add and remove contacts'
Digital Certificates.
Storing Digital Certificates from a received
signed message
This is the simplest way to get somebody’s Digital Certificate so you can send
them encrypted e-mail. When you receive a signed message from someone, you can easily
store their Digital Certificates in your Address Book:
- Open the signed message with Outlook Express 5.
- On the File menu, click Properties.
- Click the Security tab, and then click "Add to Address Book".
When a contact has a digital ID, a red ribbon is added to their entry in your Address Book
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Importing Digital Certificates into the Contacts Folders
To import a previously downloaded Digital Certificate into your Contacts folder:
- In Outlook Express 5, create a new contact or open an existing one in your Address Book
- Choose the "Digital ID's" tab
- Click on the "Import" button
- Locate and select the Digital Certificate you just downloaded and click the Open button.
- Click on "Save and close".
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