Screen memory and privacy: what to look for

A screen memory is the most intimate app you can install. It sees everything you see. The good ones make that safe; the careless ones make it a liability. Here are the ten questions we asked ourselves when building DejaVu, and that we think you should ask of any app — ours included.

1. Where is your screen processed?

The first question, and the most important. On your Mac, or uploaded to a server to be read, summarised or “understood”? If pictures or text leave your Mac, your screen now exists on someone else’s computer, under someone else’s retention policy. Look for an explicit statement, and for an app that keeps working with your Wi-Fi off.

2. What exactly does it keep?

Pictures of your screen and their text are what you need to find things again. Some apps also keep audio (your meetings, and the people in them) or what you type (keystrokes). Each of those adds risk: keystroke logs catch passwords typed in ordinary fields and messages you deleted before sending; audio records people who didn’t consent. If you don’t need them, choose an app that never keeps them.

3. Is it encrypted on disk?

Files in your user folder can be read by anything running as you — including malware. A screen memory should be encrypted, with its key protected by the Mac’s security hardware rather than sitting in a file next to the data.

4. Who can open the history?

Encryption means little if the history opens for anyone at your unlocked Mac. Look for Touch ID (or a password) to look back, and a history that locks itself again after a few minutes and when your screen locks. Bonus points if the part that records can’t read the past at all.

5. What does it skip by default?

Nobody should have to configure the obvious. A careful app never keeps password managers, keeps nothing while you type a password, and skips private browsing windows and video calls without being asked. Check the default list.

6. Can you stop it in one click?

Sensitive moments happen without warning. You should be able to pause in one click and forget the last few minutes in one click, without opening settings.

7. Can you exclude what you want?

Your bank, your health portal, a work tool you shouldn’t keep: you should decide what is never remembered — by app and by website.

8. Does deleting really delete?

On an SSD, deleting a file doesn’t guarantee it is gone. Ask whether deleting removes pictures, text and the search index together — and whether old backups can bring it back.

9. Can you take your data with you?

Apps get acquired, pivot or shut down; Rewind did. An open, documented export means your memory outlives the app. And an app that doesn’t depend on its maker’s servers keeps working if the company changes plans.

10. Who makes it, and how is it paid for?

You are trusting someone with your screen. Is the developer identifiable? Is the app signed and notarized by Apple? Does it contain analytics or telemetry? Is it paid for by you, or by something else?

A note on “privacy” claims

No filter is perfect. A password typed into an ordinary field, or a code shown without context, can slip through the best exclusion list. An honest app says so, and gives you pause for the moments that matter. Be wary of words like “unhackable” or “100% secure”.

Check any app in five minutes

We turned these questions into a free, interactive screen memory privacy checklist. Answer for the app you are considering; you get a score and the questions worth sending to its developer. It runs in your browser, and nothing you enter leaves the page.

And if you want to know how DejaVu answers: no cloud, no audio, no keystrokes, encrypted with a key protected by the Secure Enclave, Touch ID to look back, password managers and private windows skipped, one-click pause and forget, real deletion, open export with Pro. The details are in How DejaVu protects your memory.