Questions[secure-erase](ubuntu)

I think I didn't encrypt my drive when I installed Ubuntu and I would like to use the opportunity to change that when I install Ubuntu 20.04. I'd like to make sure that all data is permanently wiped before I do a fresh installation, but that's turning out to be a bit of a problem. All I found online on the topic was the advice to go on the manufacturer's website to see how to proceed.

I have a Samsung 970 EVO SSD, and the tool that Samsung offers (Samung Magician) appears to be available exclusively for Windows. Any ideas how to get this done?

I downloaded latest stable Ubuntu (ubuntu-16.04.3-desktop-amd64.iso image that I double checked for authenticity) and used it to boot my new Win10 system which I wanted to wipe. I followed the instructions, like those at

https://ata.wiki.kernel.org/index.php/ATA_Secure_Erase

to unfreeze the drive and wipe it using the

time hdparm --user-master u --security-erase ... /dev/sda3

command. In fact I ran it another time (after resetting the drive password) and running with --security-erase-enhanced option second time (thanks to http://www.stevenmaude.co.uk/posts/securely-erasing-frozen-hard-disks-with-hdparm instructions).

It took almost 2 hours each time to go through the erase process. At the end, no errors were printed out. 0's were shown for various times, like 0 cpu time and 0 system time. Only the elapsed time was showing ~2 hours.

After those two runs, I was still able to open random text and xml files in both Windows and non-Windows directories and look at their contents even though I had not opened them earlier in that same Ubuntu session, so it could not have cached them!

then...

• I could no longer boot into Windows - guess that's a good sign :-)

• After restarting computer and loading up Ubuntu again, it no longer auto-mounts /dev/sda3 (or anything else resembling a hard drive). fdisk -l shows the drive but that's about it.

• Tried loading Paragon bootable CD and it also shows no filesystem.

Any ideas as to what I am missing?

It's almost as if it blew away the entry into the file system but after the two erases it was still able to navigate and find file content in that same session of running Ubuntu. Now I don't seem to be able to see anything because anything I try to run no longer finds starting point for the file system, but I wonder if all the data is still laid out there on disk?!

Thank you!

Regarding the secure-delete command in Linux, what is the difference between srm -f, srm -l and srm -fl ? Which is fastest? Which is most secure?

My company purchased an Ubuntu computer we are returning due to hardware issues.

How can I erase my account? I was going to erase the user will this be sufficient.

These guys are honest businessmen I just have logs and other sensitive data on here.

This is in regards to the actual "wipe" command. I've looked through the man page and not gotten an answer. I've been unable to find any documentation online which explains what the verbose output means. Does anyone have any insight?

The above output is from a "quick" wipe (N number of passes with random data). Some files (small in size) wipe relatively quickly so the output lists the total bytes wiped. But others show a progress which displays [ x / y], where value "x" counts up during each wipe iteration. And it's unclear what the value of "y" is. In the above image, "4228" what? That value remains constant with each iteration. The file in question is about 64MB in size.

The second image here is taken from wiping a copy of the same file, but in "standard" mode, which performs ~34 passes. In the standard mode, what does the value in parenthesis "(14)" mean? This value seems to change with each pass.