Secure Erase is a firmware erasure method built into some drives. When available, a command is sent to the firmware of the drive, and the firmware quickly overwrites every sector with a 1 or 0. Since it is an internal process, it is a very quick process. WipeDrive has the ability to determine if the drive can do Secure Erase, and will attempt to use that command to wipe the drive more efficiently. If a 3 pass pattern is selected in WipeDrive, for example, it will attempt to use Secure Erase during one of the passes. We now indicate on our logs whether a Secure Erase pass has been completed in order to comply with NIST standards if a NIST pattern is chosen.
If Secure Erase is not supported, WipeDrive then does the process manually. Depending on the wipe pattern chosen, WipeDrive will overwrite each sector of the drive with the appropriate data.
Here is a web site that gives a brief overview of Secure Erase: https://www.lifewire.com/what-is-secure-erase-2626004