A Simple Guide to Encryption

Encryption transforms your information into a scrambled code. Only someone with the right key can unscramble it and read it. It is one of the most effective ways to protect your personal information and stop unauthorised people getting at it.

Start with a strong password

Your encryption key is only as safe as the password protecting it. Before you encrypt anything, make sure your password is up to the job.

• Use at least 12 characters.
• Mix uppercase and lowercase letters, numbers, and symbols.
• Avoid obvious words, names, or dates.

A strong password means that even if someone gets hold of your encrypted files, they still cannot open them. You can find more advice in our guide to staying safe from common scams, which covers password basics.

Use encryption software

You do not need to be technical to encrypt your data. Most computers already come with encryption tools built in.

• BitLocker is built into Windows. It can encrypt your whole hard drive, individual folders, or a USB stick.
• FileVault does the same job on a Mac.

Both tools are straightforward to switch on and work quietly in the background once they are set up.

Choose the right type of encryption

There are two main types of encryption. You do not need to memorise the technical details, but it helps to know the difference.

• Symmetric encryption uses one key to lock and unlock your data. It is simpler to set up.
• Asymmetric encryption uses two separate keys: one to lock the data and a different one to unlock it. It is generally considered more secure, but it is also more complex to configure.

For most home users and small businesses, the built-in tools mentioned above handle this choice for you automatically.

Back up your encryption key

If you lose your encryption key, you lose access to your encrypted data. There is usually no way to recover it. So backing up your key is essential.

• Save a copy to an external hard drive that you store somewhere safe.
• Or use a reputable cloud storage service.
• Keep the backup separate from the device it protects.

Our article on why backing up your devices matters has more practical tips on keeping copies of important data safe.

Know the limitations

Encryption is powerful, but it is not a complete solution on its own. Here are a few things to keep in mind.

• If someone sits down at your unlocked computer, they can read your files without needing the key. Always lock your screen when you step away.
• Encryption software can sometimes have security weaknesses. Keeping it updated closes those gaps.
• Encryption protects data at rest. It does not automatically protect you from phishing, malware, or other threats.

Use encryption alongside a firewall and up-to-date antivirus software for the best protection.

Keep your software up to date

Security researchers regularly find and fix weaknesses in software, including encryption tools. Installing updates as soon as they are available means you benefit from those fixes straight away.

Our guide on how to keep your devices up to date walks you through the process step by step.

Trusted references

• NCSC small business cyber security guide
• Cyber Aware campaign