But Amal Graafstra is different. For the last 10 years, he's been busy hacking into his own body.

His US company Dangerous Things specialises in manufacturing rice grain-sized computer chips designed to be implanted inside the delicate webbing between the thumb and forefinger.

"Getting an ear piercing is many times more risky," he says, reassuringly.

The bionic-grade glass chips use radio-frequency identification (RFID) to control electronic objects with the swipe of a hand - from the lock on a front door to a car ignition or a personal computer.

It's the same kind of technology used in pet ID tags; by itself, the chip doesn't do much, but when it comes into close contact with a "reader" device, it will transmit information that can then trigger commands.

The chips only cost $US99 a pop, and while their core market is a handful of dedicated geeks - including a few in Australia - Graafstra says he's increasingly noticing a new kind of customer.

"What is becoming clear is there are more individuals purchasing the chips who have less knowledge about the technology," he says.

"They're into gadgets and they're geeky but they're not necessarily building their own stuff, so the type of customer is expanding slowly."

RFID chips are becoming more common elsewhere, too.

The most well-known standard of RFID is near-field communication (NFC), increasingly used in instant, digital payment transactions, which facilitate credit card payments in a matter of seconds with a simple tap.

Visa this week announced a partnership with the University of Technology Sydney to develop new wearable technologies.

Alongside the announcement came a sensational figure from its own research, purporting to show that a quarter of Australians were "at least slightly interested" in having an NFC chip implanted in their skin for payments.

Visa and UTS have since clarified they were not actively developing implant technologies themselves, but the alarm bells are already ringing.

Social futurist Mal Fletcher, who heads up the London-based think tank 2020 Plus, responded with an Op Ed warning of the potential pitfalls of "subcutaneous spending devices".

These included bodily hacking; mass surveillance from commercial parties collecting our personal data; rising instances of "digital debt" thanks to the abolition of physical money and its tangible value associations; links between implants and cancer; and even the potential to cause early-onset dementia.

Fletcher insists he's not an alarmist - just cautious.

"We have to look at not just where technology is now but the principle behind it," he says.

"I'm not trying to make payments companies into the bogyman," he says. But he points out that it is in their interests to lead the push towards a cashless society, where ease of transactions and detachment from money encourage impulse spending - and everyone's spending habits are dutifully logged.

Graafstra counters that chip implants are not too far removed from where we are today, where day-to-day living depends on the binary transactions of bank cards, swipe cards and serial numbers - all traceable back to our ID.

"We're already in a position where we have no real control over our digital assets," he says.

At least chip implants can eliminate the stress of being mugged - or can they?

The threat of hacking RFID chips is real, says Linus Information Security Solutions director Mike Thompson, and the upsides may not be worth it.

The assumption that NFC chips can only be read at very short distances is misplaced, he says, citing "plenty of examples" where people have accessed them over distances of several metres using specialised antennas.

These security flaws can be mitigated with the addition of passcodes or PINs - which can be added to smartphones or wearables, but not to the palm of your hand (yet).

An aluminium shield also works; for instance, a special aluminium wallet to protect your NFC-enabled credit card from would-be hackers.

Thompson is sceptical of the advantages of embedding chips into one's body over, say, clothing or other wearable devices.

"Is opening a door automatically when you are naked that important?"