Communicator Help: Using AOL<sup><font size=-2>®</font></sup> Communicator Mail

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Using AOL Communicator Mail

Signing & Encrypting Messages

The sections that follow describe how to obtain, set up, and use certificates to sign and encrypt your e-mail messages.

Setting Up Secure Mail
HOW IT WORKS: Digital Signatures & Encryption
Getting Other People's Certificates
Configuring Security for an Account
Signing & Encrypting a New Message
Reading Signed & Encrypted Messages

Related topics:

Getting Started With Identity Manager describes how to configure your existing certificates to support signed and encrypted mail messages.

For additional information on digital signatures, encryption, and the Identity Manager, see Using AOL Communicator Identity Manager.

For information on using the Message Security Info windows, see Mail Settings & Preferences.

Setting Up Secure Mail

When you compose a mail message, you can choose to attach your digital signature to it. A digital signature helps recipients of the message to verify that the message really comes from you and decreases the possibility that the message has been tampered with since you sent it.

You can also choose to encrypt a mail message. Encryption makes it more difficult for anyone other than the intended recipient to read the message while it is in transit over the Internet.

Before you can sign or encrypt a message, you must take these preliminary steps:

1. Obtain one or more certificates (the digital equivalents of ID cards). For details, see Getting Your Own Certificate.
2. Configure the security settings for your e-mail account. For details, see Configuring Security for an Account.

Once you have completed these steps, you can complete the instructions in Signing & Encrypting a New Message.

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HOW IT WORKS: Digital Signatures & Encryption

A digital signature:

Identifies the sender of the message.
Helps detect tampering with the message after it was sent.

To create a digital signature for an e-mail message that you are sending, you need two things:

A signing certificate that identifies you for this purpose. Every time you sign a message, your signing certificate is included with the message.
A certificate is a bit like your name and phone number in the phonebook—it is public information that helps other people communicate with you.
A private key, which is created and stored on your computer when you first obtain a certificate. Every private key corresponds to a public key included with your certificate.
Your private keys are protected by your Master Password.

Mail uses your private key to create a unique, verifiable digital signature for every message you choose to sign. The public key in your signing certificate allows other people to confirm that your private key, and nobody else's, was used to create the signature.

To encrypt an e-mail message, you must have an encryption certificate for each of the message's recipients. The public key in each certificate is used to encrypt the message for that recipient.

If you don't have a certificate for even a single recipient, the message cannot be encrypted.

The recipient's software uses the recipient's private key, which remains on that person's computer, to decrypt the message.

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Getting Other People's Certificates

Every time you send a digitally signed message, your encryption certificate is included with the message. Therefore, one of the easiest ways to obtain someone else's certificate is for that person to send you a digitally signed message.

When you receive such a message, the person's certificate is automatically stored by Identity Manager. This is useful because you need to have a certificate for each recipient of any e-mail message that you want to send in encrypted form.

Another way to obtain certificates is to look them up in an online directory, such as the "phonebook" directories maintained by many companies.

It's also possible to look up certificates automatically. When you are using any account that is configured to look up addresses in a directory, the same directory will be searched for matching certificates when you attempt to send an encrypted message to one or more recipients for whom you don't have certificates on file.

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Configuring Security for an Account

Once you've obtained one or more certificates for signing and encrypting mail messages, you can configure your Mail accounts to use them.

To specify which signing and encryption certificates to use with a particular identity, begin from the Mail window:

1. Open the Edit menu and choose Account Settings.
2. Double-click the name of the account for which you want to configure certificates.
3. Click the Security tab and adjust the settings as necessary:
   Digitally sign messages by default: If you want new messages to be digitally signed by default, select this checkbox.
   This setting is optional. Even if it's not selected, you can still choose to digitally sign an individual message when you write it.
   Use this certificate to digitally sign messages sent from this account: Choose the signing certificate you want to use from the drop-down list.
   You must choose a signing certificate here before you can encrypt or digitally sign any message sent from this account.
   Encrypt messages by default: If you want new messages to have encryption turned on by default, select this checkbox.
   This setting is optional. Even if it's not selected, you can still choose to encrypt an individual message when you write it.
   Use this certificate to encrypt and decrypt messages for this account: Choose the encryption certificate you want to use from the drop-down list.
   You must choose an encryption certificate here before you can encrypt or digitally sign any message sent from this account.
4. Click OK to confirm your choices.
5. Click OK in the Account Settings window.

In some cases you may be able to specify the same certificate for both signing and encryption. Check with your system administrator to find out for sure.

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Signing & Encrypting a New Message

Before you can digitally sign or encrypt any message, you must obtain at least one e-mail certificate and configure secure mail for at least one of your identities. For details, see Setting Up Secure Mail An identity's secure mail settings also determine the default settings for new Write Mail windows.

To open a Write Mail window, start from the Mail window and click Write Mail.

To view or change the current security settings for the Write Mail window you are viewing:

1. Press and hold the mouse button while the pointer is over the lock button near the top of the window.
2. Choose Digitally Sign or Encrypt to select or deselect those options in the drop-down list.

To view more detailed information about the message's security status, open the View menu and choose Message Security Info.

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Reading Signed & Encrypted Messages

When you view a signed or encrypted message in the Mail window, these icons near the upper-right corner of the message header indicate the security status of the message:

The message is digitally signed and
has been validated. If there is a
problem with the signature, the pen is
broken.

The message is signed, but it has a
large attachment that has not yet
been downloaded. Click the icon to
download the attachment and
validate the signature.

The message is encrypted. If there is
a problem with the encryption, the
lock is broken.

To see more detailed information about the message's security, click the key or lock icon.

For information about certificate validation, see Controlling Certificate Validation.

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The sections in this document that discuss security, encryption, and privacy are provided by AOL for your information only. They may help you take certain steps to protect the privacy and security of your personal information on the Internet. This document does not, however, address all online privacy and security issues, nor does it represent a recommendation by AOL about what constitutes adequate privacy and security protection on the Internet.

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Last Updated September 16, 2003