After making purchase, you’ll only be able to download a .sdx file. This file can be opened by SDM (Secure Download Manager), which is not available in Linux. Fortunately, we have an alternative: Linux SDM Downloader. Clone Linux SDM Downloader’s source code, enter its folder, and run:

$ python ms-software.sdx

You’ll get a .sdc file and a .sdc.key file. Next you need another tool to decrypt the sdc file together with the key: xSDM

$ xsdm ms-software.sdc

Make sure that your sdc and sdc.key are located in the same folder.