Spotlight: Untapped AI wants to prove where a phone call really comes from

Untapped AI, a Cape Town company that builds AI voice agents for businesses, has filed US patent applications for a way to prove where a phone call is really coming from. The aim is to stop criminals who use cloned voices and spoofed numbers to pose as banks, employers or family members.

It matters here because South Africans lost about R2.4bn to digital banking crime in 2025, across 110,074 reported incidents, according to the South African Banking Risk Information Centre (Sabric). Sabric says most of that crime relies on social engineering such as impersonation and voice phishing, not on breaking into bank systems.

The technology is not live. Untapped AI says it has been tested, and director Lloyd Matthew told TechCentral the company is in talks with a major mobile network that he would not name. Nobody is protected until a network or a business switches it on at both ends of a call.

What the company says it does

Untapped AI was founded by Matthew, who is also its chief executive, and has offices in Cape Town and Johannesburg. In January it said it was the first local provider to run an AI voice agent whose calls are routed entirely through a South African exchange.

Its 28 September announcement described one patent application: a handshake that lets two AI agents on a call establish who each represents before anything sensitive is shared. A signal hidden in ordinary-sounding speech tells the agents they are talking to a compatible machine. They then open a separate encrypted data link and use the call to confirm that the party on the link is the party on the line. The check is generated fresh for every call, so a recording from one call cannot be replayed on another.

Matthew gave TechCentral a broader picture of two filings made in September. One uses a cryptographic key that changes with every call, exchanged either at the network switch or carried inside the call audio as a signal people cannot hear. The other analyses the audio itself: its frequencies, gaps and other signal markers. He said the system does not trust the number shown on screen and does not try to recognise a person's voice. "We verify where the voice is coming from, which means the source of the call," he said.

That differs from the company's own release, which spoke of authenticating "the voice on a phone call". Asked about the gap, Matthew said both descriptions were accurate and that the wording could have been clearer.

The release names Heinz Vollmer as co-inventor. Vollmer is chief executive of Yaxxa, a business telecoms and contact-centre provider, which has invested in Untapped AI. Neither side has disclosed the amount.

The offer to rivals

Untapped AI says South African businesses, competitors included, may build the handshake into their own services and use the code without paying, as long as they do not resell the method as their own product. International platforms will be considered case by case. Matthew also told TechCentral he wants policy that moves liability for call fraud from customers to the businesses whose channels are abused, and that the company would share its code with the market if that happened.

The first target sectors are banking and healthcare. The company is asking banks, insurers, medical schemes, hospital groups, telecoms operators and local voice AI builders to sign up as early partners.

What outside experts said

The people TechCentral asked were cautious. Martin Olivier, a computer science professor at the University of Pretoria, said he could not fully judge the claims from what has been published, and warned that networks which compress audio may distort embedded signals. Andries Maritz, principal product manager at Entersekt, called the approach "a meaningful step forward, with conditions", noting that a network can only check calls that cross it, so banks would still need other controls.

Sabric said call authentication should not be treated as a standalone fix. It also said it cannot tell how much of the R2.4bn loss began with a phone call, and that current evidence does not show AI voice cloning overtaking conventional social engineering in South Africa. MTN said any national framework should be built jointly by operators, regulators and technology providers.

What is still open

The filings are applications, not granted patents, and Untapped AI has described the method only in broad terms. It has published no test results, no pricing for network-level deployment and no name for the operator it is talking to. Whether an inaudible signal survives compressed mobile and VoIP networks, and who pays to install it at both ends of a call, are the questions any bank or operator will ask first.