A system, method and computer-readable medium for generating a data masking syntactic definition for a data element of an unknown data type, including generating one or more alphabets corresponding to one or more element member positions of the data element based at least in part on element members occurring at each element member position in a plurality of data elements of the unknown type, each alphabet comprising a set of one or more sequential element members that have occurred in the plurality of data elements at an element member position and generating a positional map describing a syntactic structure of the data element by mapping at least one of the one or more alphabets to each element member position of the data element.