DESlock+ has a plugins compatible with Microsoft Outlook from version 2003 onwards.

When composing an email, there is a DESlock+ tab at the top of the window

When encrypting an email, the user has three options.

1. Encrypt Now
2. Encrypt On Send 
3. Encrypt And Send

The 'Encrypt Now' button when clicked will encrypt the email in its current state. For example, if the user were to add an attachment to the email and then clicked the 'Encrypt Now' button the attachment would then become encrypted, allowing the user to then type a plain text body to the email or vice versa.

The 'Encrypt On Send' button acts as a toggle button with an on and off setting. When the 'Encrypt On Send' button is activated, it will be highlighted in orange (as shown below). When the 'Send' button is clicked the email will be sent encrypted.

The 'Encrypt And Send' button combines the functionality of both the 'Encrypt Now' button and the 'Send' button. 

Upon completing your email and then choosing your method of encrypting the email, you will be presented with the following window. From here, you can select from the list of encryption keys that are available for you to use and click 'OK'.

If however, the recipient of the encrypted email does not have DESlock+ installed on their machine, they can still receive and decipher an encrypted email, but the email will need to be encrypted using a password. To do this, the radio button next to 'Use Password' will need to be selected as shown below.

The password used to encrypt the email will be subject to password policy. When encrypting an email with a password, it is recommended that the email recipient is notified of the password to decrypt the email by any means other than email.

Once the recipient has received the encrypted email, they can decrypt it if they are within the same organisation as the sender and share the key used to encrypt the email. Outlook can also be set up to automatically decrypt all emails received, although this is dependent on the recipient being privy to the key used to encrypt it. Below is an encrypted email as the recipient would view it.

If the recipient of the encrypted email is not a DESlock+ customer, the encrypted email can be decrypted with the free DESlock+ reader.

Related Articles:

How do I decrypt an email or document when DESlock+ is not installed?
What are the minimum requirements to use the Outlook plug-in?