Secure erase external SSD on older iMac?
How can I securely (and easily) erase or reliably encrypt an external SSD before sending it out into the world?
Details:
I purchased a 4 TB external SSD drive for my old iMac (Retina 5K 27", Late 2015) which is running macOS Big Sur 11.7.10. This external SSD (which I will refer to here as "Orange SSD" for short) was used for backups of the iMac's internal drive a few times, but I am no longer using it since I have decided to switch to a different drive (I got another, different-brand external SSD which I am now happily using - I'll refer to that as "Keeper SSD" for short).
I did full backups of my boot drive a couple times using the Orange SSD, so it has had data written to it (only a few times), but those backups included sensitive files (bank account info, login credentials, etc.). That would be no big deal if intended to keep the drive and use it regularly (my stuff is at home and I'm confident it's secure here). However, this Orange SSD drive was expensive and I plan to return it soon (it's still within the return window). My concern is if the data on the drive could be recovered (I realize that's unlikely, but I'd rather be safe and not even potentially expose sensitive data if I can do that). I have simply deleted all the files on the drive, but...
Because it's an SSD, the secure erase feature in Disk Utility can't be used.
Since it's an older (non-Apple silicon) Mac, and because I have never used FileVault, it's not encrypted.
My question is:
What's the best way to securely erase or reliably encrypt the external SSD ("Orange SSD") before returning it?
Worth noting:
- I realize that there are different degrees of security/paranoia/methods & efforts required (for both securing and recovering) such things. I'm looking for a reasonable balance.
- I don't need NSA/black-ops/sci-fi level security, just want to be sure that anyone who isn't with a three-letter agency or some other nefarious and skilled and determined (pick any two...) actor couldn't recover the data that I once wrote to it.
- I have never used File Vault, I rarely use terminal commands (but I can in a pinch) and I realize nothing is perfect. I'd also like to avoid making this a multi-day project before I return the drive, so simple-and-easy (or simple enough and easy enough) get extra points over "completely impossible for even the NSA to crack" absolutism. I'm trying to be reasonable.
- I'd rather not turn on encryption or take any additional security measures for the remaining drives attached to this computer - anything that I need to do to address this, I'd prefer to only do that to the drive that's about to go away, not add additional complexity to what I use every day.
So what's the smart thing to do here to prepare Orange SSD for it's return to who-knows-where it might end up?
Thanks for pointing me to the optimal way for this.
