Cape Town company Untapped AI said it filed two patent applications in the US in September. The technology aims to prove where a phone call is really coming from.
The company said it wants to stop criminals who use AI to clone voices. These criminals pretend to be banks, bosses or family members, TechCentral reported.
“Using a deepfake to get through our security is like a person expecting to draw cash from an ATM with a stolen card while wearing a mask of the owner. The machine doesn’t look at your face. It wants the Pin,” director Lloyd Matthew said.
The technology has been tested but is not yet live. It will only protect people once mobile networks or businesses install it at both ends of a call.
Untapped AI builds AI voice agents for businesses. It has offices in Cape Town and Johannesburg. Its backers include business telecoms and contact centre provider Yaxxa, whose CEO Heinz Vollmer confirmed the investment.
Matthew said the system has two parts, but he would only describe them broadly for security reasons. Both use a secret code key that changes with every call.
He said the key is either swapped at the network switch when the call connects, or carried inside the call audio. In the audio, it is a signal people cannot hear.
The second part checks the sound’s frequency, gaps and other signal markers. “We verify where the voice is coming from, which means the source of the call,” Matthew said.
The company would not explain its process in detail or publish test results. “We are deliberately vague beyond that, because we don’t want to describe the actual process publicly,” Matthew said.
South Africans lost R2.4-billion to digital banking crime in 2025, according to the South African Banking Risk Information Centre (Sabric). There were more than 110 000 reported incidents.
Sabric said it cannot say how much of that loss started with a phone call. It said AI voice cloning is an emerging risk, but has not overtaken normal scams in South Africa.
Prof Martin Olivier of the University of Pretoria said he could not fully judge the claim from the information available. “It’s a well-known mantra of cryptography that secrecy tends to point to something about the system that needs to be hidden,” he said.
Olivier said a proven cipher, used properly, would stop a clone. He warned that networks that compress audio may distort signals.
Andries Maritz, principal product manager at Entersekt, said a signal inside the call audio is a step forward, with conditions. “A fraudster using VoIP or another route bypasses it, so banks still need other controls,” he said.
Sabric said call authentication should not be seen as a standalone solution. It warned that criminals may move to WhatsApp, SMS, email or social media.
Matthew said he hopes the government will make the business, not the customer, carry the loss from call fraud. If that happens, the company will share its code with the market, including competitors, he said.
MTN said any national framework should be built jointly by industry, regulators and technology providers.
Until the system is live, Matthew advised families to agree on a code word. He said people should hang up if a caller asks for money or a Pin, and call back on a saved number.
Source: this article is based on reporting by TechCentral. Image: TechCentral. Written with the help of AI and published by the Tzaneen Voice Technology desk. See our Editorial Standards.
Werner Jacobs covers technology for Tzaneen Voice. Werner reports on mobile networks, data prices, internet access, smartphones, apps, AI, cybersecurity and South African tech companies. Each story explains what a new product, price change or policy means for ordinary users in South Africa.