A storage device, including at least one nonvolatile memory device configured to store data; and a storage controller configured to: generate a virtual table including a plurality of random values, wherein each random value of the plurality of random values designates an index from among a plurality of indexes corresponding to a plurality of main functions; transmit the virtual table to a host; receive from the host a vendor unique command (VUC) generated by the host based on the virtual table; parse the VUC based on the virtual table, perform an operation corresponding to the at least one nonvolatile memory device based on the parsed VUC; and transmit a result of the operation to the host.