Researchers found a way to watch CPU transistors work, and it could become a future security headache

A research team at the University of Adelaide has demonstrated a new way to observe what is happening inside a processor while it is actually running, using terahertz radiation.

That might sound like pure lab curiosity, but it has two big implications. First, it could give engineers a powerful new method for testing and diagnosing chips. Second, if the technique becomes practical outside the lab, it could open the door to a new kind of hardware-side data theft.

What the researchers found

According to the report, the team was able to detect transistor activity in a working chip by firing terahertz waves at it and analysing how the returning signal changed as the transistors switched on and off.

The setup uses a vector network analyser, or VNA, which starts by generating a microwave signal with a known frequency and phase. A frequency extender then converts that microwave signal into a terahertz wave, which is focused onto the microchip through a lens.

The important part is that the chip has to be powered on and doing actual work. As its transistors change state, those changes affect the reflected terahertz signal. The returning signal is then captured, converted back down to microwave, and compared against the original using a homodyne quadrature receiver that can spot tiny differences in amplitude and phase.

One of the researchers, Withawat Withayachumnankul, said the team even had to modify the receiver to make it function in the terahertz domain, since it was originally built for microwave comparisons. That matters because the signal differences are extremely small. Terahertz waves are physically much larger than the transistors being examined, and oscillator noise from the VNA can easily drown out the useful data.

Why this matters

The standout detail here is simple: this method can look into a processor while it is operating. The report says that is something existing tools cannot do in the same way.

For chip engineers, that could be a big deal. Better live analysis means better fault detection, deeper validation, and potentially faster ways to understand how a processor behaves under real workloads.

For readers in Malaysia and the wider SEA region, this is worth watching because our PC gaming and esports ecosystem keeps getting more hardware-driven. Competitive players, streamers, gaming cafés, boutique PC builders, and system integrators all depend on processors that are fast, stable, and trustworthy. Any breakthrough in chip testing can eventually trickle down into better hardware reliability.

The catch: stacked chips are a problem

This is not ready to become an everyday tool yet.

One major limitation is modern chip complexity. The report notes that densely packed designs, especially processors with multiple layers or 3D stacked chiplets, are harder to analyse because the radiation may not be able to tell which layer it is actually reading if upper layers block the view.

Researchers are reportedly discussing ways to improve the VNA's sensitivity so it can handle these more advanced designs more accurately.

The bigger concern: security

The more unsettling angle is the security risk.

If this technology matures far enough, attackers could theoretically use it to probe a CPU while it is running and extract useful data. That is especially worrying because standard encryption would not fully solve the issue. At some point, the processor still has to decrypt data before it can process it, which creates an opening at the hardware level.

That does not mean gamers in SEA need to panic tomorrow. Right now, this still sounds like specialised lab-grade work, not an attack you are going to see at your local LAN event. But it is the kind of research the hardware and security industries will have to pay attention to early, before the technique becomes easier and cheaper to use.

For now, this looks like one of those discoveries that sits in two worlds at once: exciting for chip diagnostics, and slightly alarming for future hardware security.

Source: Tom's Hardware