I was erasing a SSD with ATA secure erase and thought about the following:
When enhanced secure erase is performed on a SSD or NVMe which supports this operation, the master key which is used to encrypt all data is erased and newly generated, so that all written data can't be read anymore. So far so good. The process only took a few seconds.
After that I looked at the SSD with a hex editor and noticed - all data was erased, everthing was 0.
If only the master key was new generated, should't I see some sort of gibberish data? With the new key, all previous data shouldn't make sense now.