Virtual Private Network (VPN)
A VPN (Virtual Private Network) is a private network that uses a public network such as the Internet to connect remote sites or users. In the examples in this report, the VPNs were secured at both ends by digital certificates (mechanisms that enable the recipient of a message to verify that the sender is who he or she claims to be, and to respond to the message with an encoded reply). Election jurisdictions may use VPNs in an effort to ensure the security of electronically transmitted balloting materials.
Source: COUNTING VOTES 2012: A State by State Look at Voting Technology Preparedness, Verified Voting Foundation, Rutgers School of Law - Newark Constitutional Litigation Clinic & Common Cause Education Fund, https://countingvotes.org/sites/default/files/CountingVotes2012_Final_August2012.pdf