Screens in public: shoulder surfing, cafes, and trains

Some of the oldest attacks need no technology at all. Shoulder surfing, simply reading someone's screen or watching them type, works because people forget they are visible.

Assume you can be seen

On a train, the passenger behind you can read your screen for the whole journey. In a cafe, anyone at the next table can watch you type a password. Phone cameras make this worse: a photo of your screen takes a second and you will never know it happened. Client names, salary details, incident reports, and login pages have all been leaked this way. Before you open something sensitive in public, ask whether you would be comfortable with the stranger next to you reading it, because they can.

Practical defences

• Sit with your back to a wall where possible, so nobody is behind your screen.
• Use a privacy screen filter on your laptop. It narrows the viewing angle so the display looks dark to anyone not directly in front of it. If your role involves regular travel with sensitive data, ask IT for one.
• Dim your screen and increase your distance from others when handling anything sensitive.
• Shield your keyboard or screen when typing passwords or unlock PINs, exactly as you would shield a cash machine PIN.

Conversations carry too

What's true for screens is true for voices. A confidential call taken loudly on a train shares client information with an entire carriage. Take sensitive calls somewhere private, use headphones so at least one side of the conversation stays quiet, keep names and specifics vague in public, and offer to call back when somewhere private if the topic turns confidential.

Lock it, even for a moment

Never leave a device unlocked and unattended in a public place, even to collect a coffee. Lock the screen and take the device with you. An unattended unlocked laptop is an open door to everything you have access to.