James Lyne has been scouring the streets of Edinburgh to test how safe homes, businesses and mobile phones are from rogue hackers.
He used a specially-modified bike to scan for weak and unsecured wireless (wifi) networks in the capital, in an awareness project called "warbiking".
Attackers can join wifi networks secretly and directly attack computers to steal money or information.
They can also view the websites a person has visited, read their emails and capture private information such as passwords.
"If you are a small business or a consumer and your network is wide open, anyone can connect to your network," Mr Lyne said.
"Once they have their foot in the digital door they can not only piggyback your network but also potentially launch attacks on your personal data."
The project was organised by the Scottish Business Resilience Centre and IT security company Sophos, backed by Police Scotland.