Bitcoin is a digital currency that's sent from user to user without the need for an intermediary. This crypto currency may not be regulated by an administrator, but it's a common payment method in casinos because it's easy to deposit and withdraw funds. Online casinos that accept bitcoins include 7 Spins, Bovada, Spartan, and Jumbabet.
Cuba is an emblematic Caribbean country in many ways, and despite difficult political relations with the US, it still attracts curiosity abroad. The communist regime banned all forms of gambling decades ago, and the ban includes online casinos. In practice the ban is not strictly enforced, and some international mobile casinos do accept Cuban players.