Two possible solutions that took a while in coming for a VoIP system are the use of virtual private networks (VPNs) and encryption techniques. The short version of a VPN is as follows:
A virtual private network (VPN) is an overlay network built on top of the public network through the use of a tunneling protocol, in which the tunnels provide for encryption, authentication and non-repudiation.
VoIP is exposed whether it is carried on a private or public network. If used on the public network, two things that should happen are to use a tunnel and to encrypt the information. However, encryption is only effective if the VoIP can be decrypted by the receiving device. Thus, it is incumbent ...