"People do not seem to understand that security and smartphones as one [single] concept simply do not exist," says Pim Donkers.
Mr Donkers is a co-founder and chief executive of Switzerland's ARMA Instruments, a technology company which produces super-secure communication devices.
He compares a smartphone to a beehive where "third parties fly in and out, to trade and misuse your data [that's] collected through all the sensors onboard".
"A smartphone as a starting point in any secure communications solution is a lost cause. It will never happen," he warns.
His profound concern about the privacy shortcomings of smartphones has been supported by a series of recent news stories, most notably revelations about the spy software known as Pegasus, a product of Israel's NSO Group.
In July, it emerged that Pegasus can be installed on iPhones and Android devices, allowing operators to extract messages, photos and emails, record calls and even secretly activate microphones and cameras.
The ability to remotely access a phone was once considered something only a handful of countries could do. But the technology has advanced very quickly and high-end espionage and surveillance powers are now in the hands of many countries and even individuals and small groups.
Some data suggest that mobile devices are particularly troubling for many people.
A Pew Research Center poll shows that 72% of Americans reported feeling that what they do while using their phone is being tracked by advertisers, technology firms or other companies.
Nearly half of the people polled by Pew said they believed that most of their online activities are tracked by the government.
"We're all inundated with headlines around data breaches, hacks and other intrusions," says Larry Pang, head of business development at IoTex which produces a security camera designed to keep data private.
"We are constantly learning that the corporations and governments that have promised to protect us, in fact, do things behind our backs for their own benefit," he says.
Those fears have spurred tech firms to sell mobile devices that bill themselves as 'ultra-secure'.
Finland's Bittium sells a phone that includes a privacy mode that disables the device's microphones, camera, and Bluetooth.
However, Tero Savolainen, Bittium's vice president, warns that a mobile device is only ever as secure as the person using it.
"Even if you have a secure phone, it doesn't mean that you are safe if the user is not educated on how to use the device securely."
As an example, Mr Savolainen says giving applications too much access to your device can compromise your security.
He adds the same can be said for having an unsecured Google account that can provide a way for cybercriminals, or others, to gain access to data.
Silent Pocket, is a US-based company that produces a range of products, including wallets, laptop sleeves and travel bags - designed to "cloak" devices and block wireless and radio-frequency identification (RFID) signals.
While the company had already been expanding for several years prior to 2020, Aaron Zar, Silent Pocket's founder and "director of disconnection" says that sales recently spiked because of concerns over contact tracing during the Covid pandemic.
"[People] don't want to be monitored, and that's always been the case. But when it's that on-the-nose and that public, people have been screaming."
Other products in the privacy market are not physical at all. Xayn, for example, is a product described as a "privacy-protecting discovery browser" for the Internet.
The company says Xayn allows users to use a Google-style search function without being identified or having their data stored.
To date, it has been downloaded by approximately 215,000 users, with the majority coming from the US, followed by the UK, Germany, the Netherlands and Russia.
"Existing approaches essentially track everything a user does when searching online," explains Dr Michael Huth, the head of the computing department at Imperial College London and Xayn's co-founder and chief research officer.
"This is particularly obvious with products such as TikTok, where one or two interactions are enough to know the user well enough to feed them videos they like," Dr Huth adds.
"This level of tracking, predictive analysis and behavioural modelling challenges not only our sense of control and autonomy, but our actual freedom."
Xayn's other co-founder and chief executive, Leif-Nissen Lundbæk says that demands for privacy are rapidly turning into a "global movement".
"The discussion around digital privacy is often focused on what is not possible and sometimes has a certain fatalistic ring to it," he says.
"The dominant discourse presents privacy and technology as enemies - but it doesn't have to be this way. Advanced technology can actually protect our digital privacy and give us back our autonomy along the way."