We've all seen movies or television shows where the hackers or spies intercept important government phone calls in attempt to bring down the establishment. And while much of this is certainly gratuitous, there are indeed many cyber criminals – some affiliated with nation-states, others acting purely for monetary gain – that would, and do, attempt to listen in on government phone calls.
To address this concern, many government bodies rely on VoIP encryption. The two most common protocols are Transport Layer Security (TLS) – which creates a secure connection – and Secure Real-Time Transport Protocol (SRTP) – which encrypts the actual data packets as they pass through the IP network. For many government organizations, tandem use of these protocols is enough.
But for the Department of Defense and other agencies in the highest echelons of national security intelligence, a need for an even more stringent standard has arisen. It's called TSG-6. Here's what you need know about it:
According to SmartCEO, federal government agencies require special, secure rooms in order to make phone calls of a certain caliber of sensitivity. These are called Sensitive Compartmented Information Facilities (SCIF). They are constructed in such a way that the materials will leave traces of "unauthorized entry or tampering." Some of them have noise generators for added security that drown out any sounds by emitting certain frequencies.
"All telephone, electrical power, security systems, data and emergency systems must be dedicated to and contained within the SCIF," SmartCEO wrote. "Any utility that enters the SCIF must terminate there and not traverse through the space."
An SCIF can be an enclosed room in a government building, or it can be a mobile facility. For it to qualify as an SCIF, it must meet the above standards for security.
Then, of course, there's the question of the actual phone being used for communication …
Enter TSG-6 technology
According to Teo Technologies, one of the leading providers of TSG-6 technology, the National Telephone Security Working Group (NTSWG), which is in charge of the "technical surveillance countermeasures (TSCM) program involving telephone system," first created TSG-6 certification as a way to ensure that no unauthorized parties could listen in on top-secret phone calls.
"It is literally spy-proof."
Like an SCIF, any TSG-6 endpoint must meet a certain set of requirements put in place by the Director of Central Intelligence Directives (DCID) and Joint Air Force Army Navy (JAFAN) that eradicate even the most infinitesimal possibility that someone could listen in on a call unbeknownst to the high-level participants. These include a set of key features such as power over Ethernet, a push-to-talk button, encryption (obviously), and "ultra-low-emissions technology" which ensures that "no audio signals from the microphone are produced on any wires leaving the phone when it is on-hook," according to SmartCEO.
So to answer the question posed in the title of this post, TSG-6 is the highest, most impenetrable form of secure VoIP in existence, and it's important because it plays an essential role in top-secret government communications.
Another way of putting it? It is literally spy-proof.