A data storage device in a distributed computing system has physical block addresses that are each allocated to multiple namespaces. To access the data storage device, a host system issues a command to the data storage device that includes an access key and a virtual block address to be accessed. The data storage device converts the virtual block address to a physical block address of the data storage device using a mapping associated with the access key. Access to a physical data block associated with a particular namespace is granted only if an access key for that namespace is provided to the data storage device.