A method and apparatus provides a mask key that is used instead of mask data. In an embodiment of the present invention, a write mask key is generated by a memory controller and transferred to a memory device that uses the write mask key to determine whether to write a data value to a storage array. A plurality of decoders, an OR logic gate tree and a binary propagation tree is used to provide the write mask key that reduces latency while using the approximate same circuit area and allows for the use of standard software tools in an embodiment of the present invention. A plurality of log.sub.2 decoders is coupled to a plurality of OR logic gates in the OR logic gate tree.