Protect your computer and devices

Just as you lock your front door, a few basic steps keep your computer, phone and tablet secure. Most take only a few minutes to set up and then look after themselves.

The essentials

1. Turn on automatic updates

   For your operating system (Windows, macOS, iOS, Android), your web browser and your apps. Most attacks use security holes that already have a fix. If your device no longer gets updates, it's time to replace it for banking.

2. Use security software

   Windows has Microsoft Defender built in. Keep it switched on. Macs, iPhones and iPads have built-in protections. Keep Google Play Protect on for Android. You don't need to pay for extra antivirus, but if you do, buy it directly from a well-known company. Never buy it from a pop-up or a cold caller.

3. Keep your firewall on

   Windows and macOS include a firewall that blocks unwanted connections. Make sure it's switched on in your security settings. Your home router also has one.

4. Secure your accounts

   Use strong, unique passwords, three random words are a good start, and turn on two-step verification, starting with your email.

5. Back up

   Back up photos and important files to the cloud or an external drive, so a broken, lost or infected device isn't a disaster.

Your home Wi-Fi

• Change the router's default admin password if it still uses one printed on a sticker that others could see.
• Use WPA2 or WPA3 security with a strong Wi-Fi password.
• Accept firmware updates from your broadband provider, or turn on auto-update in the router settings.

Public Wi-Fi

Wi-Fi in cafés, hotels and stations is convenient but you don't control it. Criminals can set up fake hotspots with names like "Free Station WiFi".

• For banking, use your mobile data (4G/5G) instead of public Wi-Fi.
• Check you're connecting to the official network. Ask staff for its exact name.
• Make sure websites use https, and use apps rather than browsers where possible.
• Turn off automatic connection to open networks in your settings.

Selling, recycling or giving away a device

Deleting files isn't enough. Old devices can still contain passwords, photos and banking data.

1. Back up anything you want to keep.
2. Sign out of your accounts, including your Apple ID or Google account and banking apps, and remove the device from your accounts online.
3. Use the built-in factory reset: Settings › General › Transfer or Reset iPhone › Erase All Content and Settings on iPhone; Settings › System › Reset on Android; Settings › Recovery › Reset this PC › Remove everything on Windows; Erase All Content and Settings on modern Macs.
4. Remove SIM and memory cards.
5. For a broken device you can't reset, remove or physically destroy the storage, or use a recycler that certifies data destruction.

The National Cyber Security Centre has a detailed guide to buying, selling and donating second-hand devices.

Last reviewed: October 2026