A method of identifying data items by wave blocks, each wave block comprising a set of unique features distinguishable from the unique features of other wave blocks. The unique features of the wave blocks are extracted and stored. A plurality of wave tags are defined, each comprising a set wave blocks. A mapping of the set of wave blocks to each wave tag is stored. A request for a wave tag to identify a data item is received and a wave tag is assigned to the data item. The wave tag is broadcasted and is captured by a capturing device, which extracts the unique features of the wave blocks. The wave tag is identified by comparing the extracted features of the wave blocks with the stored features of the plurality of wave blocks. The data item is identified from the mapping of the data item to the wave tag.