Are the MailStream Plus USPS Postal Reference Files encrypted and secured to download?

Produce affected:  MailStream Plus™ 8.3.7. All platforms, all versions.
The MailStream Plus™ Reference Files (PRFs) are not required to be encrypted-and-secured.

The USPS files contain USPS postal data.  The files do not contain any company data information that links back to customers. The USPS postal reference files are used to assist in presorting using the data provided by the USPS (i.e Labeling Lists, Zone Matrix, and ZIP Code tables.)
UPDATED:  May 16, 2019