Only the official PSN store (via gift cards) or a physical disc edition that you personally redeem. Everything else is a risk.
Throughout the campaign, Nomad and his team face off against a variety of enemies, including Soviet soldiers, Cuban rebels, and even rogue CIA agents. Along the way, they uncover a deeper conspiracy involving a shadowy organization known as the "Tranzit Consortium," which is secretly manipulating world events to further its own interests.