You first need to subscribe to the Beyond Encryption newsletter and communications, and do so here
This will lead to a screen like the one below, where you can enter your name, email and select to 'Subscribe'.
You'll then receive the confirmation as below.
At the bottom of a newsletter or marketing communications you receive from us, you'll find the two links, 'Unsubscribe' and 'Manage preferences', as shown in the image below.
Selecting 'Manage preferences' will take you to the 'Communication Preferences' screen with an individual mailing type choice. From here you can untick any of the emails listed that you don't want to receive or there's the option to tick the last box to unsubscribe from all mailing lists.