A first merchant node on a semi-private blockchain virtual currency exchange system is exclusively capable of creating first virtual currency units. Unaffiliated merchant node(s) are exclusively capable of creating other merchant-specific virtual currency units in the system, while customer computing devices are incapable of creating virtual currency units. The first merchant node creates and issues first virtual currency units to a first customer account associated with a first customer computing device. Upon receiving a transaction request for exchanging first virtual currency unit(s) for a second currency type between the first customer account and another customer account, the first merchant node validates the first transaction request, and creates and sends a first transaction receipt to unaffiliated merchant node(s). Upon receiving a redemption request from a customer account, the first merchant node validates the first redemption request, and creates and sends a first redemption receipt to unaffiliated merchant node(s).