ViennaKey - is a USB protection device by eLicenser (formerly Syncrosoft) that is required to run any Vienna Symphonic Library product. It is not included in any library or software product but has to be purchased separately. If you already have another eLicenser USB protection device (e.g., from Steinberg or Arturia), you can use it for VSL products, too. Otherwise we recommend ordering at least one ViennaKey along with your first purchase.
You can use one ViennaKey for all of your Vienna Symphonic Library products, as long as you run them on one single machine. Of course you can distribute Vienna Instruments Collections as you wish over several computers, e.g., Solo Stringsand Chamber Strings on computer A and Orchestral Strings and Brass on computer B. This will require two ViennaKeys. Working with VSL products on more than one computer simultaneously requires one ViennaKey (with the respective licenses) for each computer.*