This is probably the first time you've heard both terms. That's why, throughout this article, we want to help all those who do Email Marketing to ensure that their strategy is not based solely on designing, sending and measuring, but that they also take into account external aspects, unrelated to our daily work, that are affecting deliverability.
As I mentioned at the beginning, our mailboxes spend the day filtering emails so that we only receive the email from:
a trusted sender , that is, any email with whom we do business on a daily basis, an email from a colleague, a client, a family member.

or the promotion, eBook, newsletter, in general, the information to which we have subscribed.
But there is no doubt that Gmail, Hotmail or Yahoo receive a large number of advertising emails, which they have to analyze one by one to leave those that have passed their spam filters in your inbox and put those that have not passed their spam filters in the spam folder or not deliver them at all.
We don't usually encounter this problem in any ordinary email, but it does appear when we use Email Marketing tools, like ours, where users' campaigns must be able to pass these spam filters.
The filter we want to tell you about today is related to the security of your emails. Technological developments have made it easy for spam distributors to access the information contained in your emails, and for this reason, different ISPs reward with better deliverability all those who decide to encrypt their emails, and take care of this aspect of deliverability.