What root certificate should I install? Reference num. 3311 Views: 2377 Home / FAQ / What root certificate should I install? This is how you can check what root certificate to install: 1 Open Home menu and type in Personal. An icon will appear, as shown below. After clicking on the icon, Nexus Personal program will start. 2 Double-click on Electronic ID. 3 Open in a new window, double-click on Digital Signature, or Digital Signature-2 if you have a renewed digital certificate. 4 Check whether you have Halcom CA PO e-signature 1 or Halcom CA PO 3.