What is encryption, and when does it actually matter?
Encryption gets talked about like a magic shield. It's more specific than that, genuinely vital in two situations, and largely beside the point in most others.
// overview
Scrambled unless you hold the key.
Encryption turns readable data into nonsense that can only be turned back by someone holding the right key. That's the whole idea. The maths underneath is genuinely clever, and you never need to think about it.
What's worth understanding is when it helps, because that's where people get a false sense of safety. Encryption protects data in two situations: when it's sitting on a device someone might physically take, and when it's travelling across a network someone might listen in on.
It does nothing at all once a device is unlocked and you're logged in. If a laptop is stolen while running and open, full-disk encryption doesn't help, everything is decrypted and sitting there. This is the single most common misunderstanding we come across.
// the two kinds
At rest, and in transit.
- 01
At rest: on the device
Full-disk encryption means that if your laptop is stolen from the car, the thief has an expensive paperweight rather than your tax records and saved passwords. Windows calls it BitLocker; Macs call it FileVault. Both are free and built in.
- 02
In transit, over the network
The padlock in your browser means the connection is encrypted, so someone on the same café wi-fi can't read what you're sending. Practically every site does this now, its absence on a page asking for a password is a serious red flag.
// worth doing
Two settings and a habit.
For most people this whole topic reduces to a short checklist. Once these are on, encryption largely takes care of itself.
- Turn on BitLocker (Windows) or FileVault (Mac), and store the recovery key somewhere safe that isn't the device itself
- Set a PIN or biometric lock on your phone, modern phones encrypt by default, but only if a lock is set
- Make sure your backups are encrypted too, especially any drive that leaves the building
- Check for the padlock before entering a password or card number
- Encrypt USB sticks that carry anything sensitive: they're the easiest thing in the world to lose
// for business
Where it stops being optional.
If you hold customer records (a client list, medical details, payment information) encryption stops being a nice-to-have. Under Australia's Notifiable Data Breaches scheme, losing a laptop full of unencrypted customer data can become a reportable breach with real consequences. Losing an encrypted one usually doesn't, because the data remains unreadable.
That single distinction has saved businesses we work with a great deal of pain, and it costs nothing but ten minutes per machine.
The part that gets forgotten is recovery keys. Encryption you can't reverse is just data loss with extra steps. When we set this up we make sure the keys are escrowed properly, stored somewhere the business controls, not on a sticky note or solely in one departed employee's Microsoft account.
// questions
Good questions, straight answers.
Will encryption slow my computer down?
Not noticeably on anything made in the last decade. Modern processors handle it in hardware. If a machine is already slow, encryption isn't the cause and turning it off won't be the cure.
What happens if I forget my password?
That's what the recovery key is for, a long code generated when encryption is switched on. Save it somewhere that isn't the encrypted device: a password manager, a printed copy, or your Microsoft or Apple account. Without it, the data is genuinely unrecoverable, including by us.
Is my data encrypted in the cloud?
Generally yes, both in transit and on the provider's servers. What that doesn't protect against is someone getting into your account, which is why MFA matters more than encryption for cloud services.
Does encryption protect against ransomware?
No, and it's a common mix-up. Ransomware encrypts your files against you. Your own encryption doesn't prevent that; a tested backup does.
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