I'm using a MacBook and want to store confidential data (financial documents, passwords, private photos, etc.) on an external HDD disk.

  1. How safe is setting up APFS AES 256 encryption with disk utility?
  2. Does HDD brand and model matter for security?
  3. Are these models safe:
  • Toshiba Canvio Basics HDTB420EK3AA
  • WD 2TB Elements SE WDBEPK0020BBK-WESN
  • Transcend StoreJet 25M3S TS2TSJ25M3S
  • Seagate Expansion 2TB STKM200040

1 Answer 1


How safe is to set up APFS AES 256 encryption with disk utility?

As safe as you can get. The issues you have to account for is to use a good passphrase and never lose it. Data confidentiality will not be an issue, but data availability will if you lose the key.

Does HDD brand matter and model matter for security?


Are these models safe?

It does not matter. The HDD is just storing bits, the encryption is at least one layer above. The protection comes from the data encryption, so even a malicious HDD will only see encrypted data.

  • Thank you for reply. "The HDD is just storing bits, the encryption is at least one layer above " Is it same for USB Flash?For example if i encrypt usb flash with 256 aes ? Aug 24, 2022 at 1:18
  • It's the same for USB Flash, for 3 ¹/² floppy disks, for cloud storage, for magnetic tape, for punch cards, for CD-R, for any media.
    – ThoriumBR
    Aug 24, 2022 at 2:20
  • @alexandergill, note that: 1. it only secures your data against physical theft of a shutted down device (an executed malware would see the data in clear.) and 2. this assumes a perfect implementation of the cryptographic primitives and the software surrounding it. (E.g. thehackernews.com/2018/03/macos-apfs-password.html ) Solutions to encrypt external medias sometimes have critical vulnerabilities allowing to bypass encryption. You should verify when using one of them.
    – Yuriko
    Aug 24, 2022 at 5:20
  • @Yuriko ''an executed malware would see the data in clear''.So if i have malware on my pc or in my HDD,it would easily see all my protected files? Aug 24, 2022 at 6:48
  • 1
    @alexandergill: yes, once your computer boots and mounts the encrypted hard drive by providing the decryption key, the OS is able to access all the files as if they were unencrypted. Encryption/Decryption happens at a lower level making it transparent to the OS and the applications (incl. malwares.) For example you can see all your file unencrypted by using the Finder, TextEdit, VLC, etc. It would not be different for a malware.
    – Yuriko
    Aug 24, 2022 at 8:09

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .