Your disk is like a file cabinet, there’s also an index folder where for example it says that “your file.txt” is in cabinet C7. You go there and there’s a sheet of paper written in pencil with the contents of your file. In this analogy here’s how several solutions work:
Delete the file: throw away the index folder. Now if you need to write to disk you might think C7 is free and when you go there to write something else you find the old paper, which you erase and write on top. But if someone gets to your cabinet before that and they open C7 your file Will be there in its entirety, there just isn’t an index telling you which cabinet to open.
Zero wipe: you go to C7, erase the file, and then throw away the index. Now if someone gets to your cabinet they might go to C7 but all they see is a white sheet of paper. However it’s technically possible with a white sheet of paper to see what was written before, so this is considered better but not perfect.
Random wipe: same as before, except you erase and write random stuff on the sheet of paper. So it becomes a lot more difficult to recover what was there.
Multiple passes: Same as before, but you do this several times, so after dozens of random writes your original data should be completely impossible to recover.
It’s worth mentioning that the OS index is what gets deleted when a file is deleted, the SSD is untouched by this, but SecureErase is a special command sent to the SSD controller inside the unit that deletes its own index of what entries correspond to which 1s and 0s on which separate internal NAND flash chips (and dies, planes, blocks and pages) and in what order. This makes recovering data very very difficult even if the actual data is not overwritten in any way, because SSDs will often write in parallel for speed, which renders the oldest most bruteforcry digital forensic technique in the book on HDDs - simply transplanting the platters into a different drive, imaging them into hex and looking for file headers and subsequent zeroes (to identify empty space after a file) and reading in files as if they were written linearly to see what comes out.
Your disk is like a file cabinet, there’s also an index folder where for example it says that “your file.txt” is in cabinet C7. You go there and there’s a sheet of paper written in pencil with the contents of your file. In this analogy here’s how several solutions work:
It’s worth mentioning that the OS index is what gets deleted when a file is deleted, the SSD is untouched by this, but SecureErase is a special command sent to the SSD controller inside the unit that deletes its own index of what entries correspond to which 1s and 0s on which separate internal NAND flash chips (and dies, planes, blocks and pages) and in what order. This makes recovering data very very difficult even if the actual data is not overwritten in any way, because SSDs will often write in parallel for speed, which renders the oldest most bruteforcry digital forensic technique in the book on HDDs - simply transplanting the platters into a different drive, imaging them into hex and looking for file headers and subsequent zeroes (to identify empty space after a file) and reading in files as if they were written linearly to see what comes out.
That’s as I understand it though.