It is very common for some brand marketers to utilize more than one email platform for their email campaigns. This practice is especially true when they partner with affiliates who send emails to the same shared contact lists but on separate platforms.
It is important to ensure that a contact who opts out from the email program no longer receives emails regardless of who is sending the emails on behalf of that brand. Third parties, such as UnsubCentral, act as a centralized collecting point for email opt-outs. They share the opt-out lists with all the marketing agencies sending emails on behalf of that brand. The email addresses themselves are encrypted (typically as an MD5 hash) to maintain privacy.
How does it work?
If a campaign includes a reference to a Secure List, then Maropost for Marketing creates an MD5 hash of every email address in the campaign’s targeted audience. Next, it removes any contact from the targeted audience whose email hash is contained within the specified secure suppression list.
Managing Secure Lists
You can create and manage Secure Lists on the Secure Lists index page. In Navigation, go to AUDIENCE, and select Secure Lists.

Creating a Secure List
- In Navigation, go to AUDIENCE, and then select Secure Lists.
- On the Secure Lists index page, click New Secure List.
- Enter a name for the secure list.

- Click Save.
Importing Contact into a Secure List
After a Secure List is created, you can import contacts into the secure list as you do for your regular lists. To find information about importing contacts into regular lists, see Importing Contact Lists.
On the Secure Lists index page, find the list into which you want to import contacts. Then, from the Actions drop-down menu, select Import Select List. The Import Secure Emails dialog box opens where you can select the import method (file import or FTP import), file from which to import contacts, and other related options. The most important aspect is to select the column name or column number in which your MD5 hashed contact details are stored.