@4censord @nazokiyoubinbou @nixCraft There are two...

@4censord @nazokiyoubinbou @nixCraft There are two forms of secure erase for SSDs.

One involves flushing the key used for the wear leveling encryption. This is extremely fast, but it doesn’t actually erase the data; only makes it unreadable. Due to this, it doesn’t directly help with performance, so it is commonly followed by the second, older type.

The older type involves a voltage spike for about a tenth of a second. This completely wipes all data stored in the chip’s pages. This is the one which restores write performance, since all the pages are blank again (no mode read/erase/program cycle). Since this is a chip-level thing, it even wipes the data stored in spared pages.

Like 12 March at 23:11 | Wall-to-wall | Open on infosec.exchange

3 comments

Nazo

@bob_zim @4censord @nixCraft Oh, I misunderstood. I thought that was referring to a simple block erase like what TRIM uses. That restores performance in the same basic way, but this mechanism takes it further by more thoroughly clearing the blocks I see.

12 March at 23:14 | Open on mastodon.social

Zimmie

@nazokiyoubinbou @4censord @nixCraft Technically, TRIM erases pages. Pages on a flash chip can contain several blocks. Erasing a single flash page is basically the voltage spike, but to only the one page and for a shorter time. The chip-level erase lasts longer in part to make sure everything gets fully saturated.

Different trigger and different scale of effect, but it’s the same mechanism.

12 March at 23:24 | Open on infosec.exchange

Nazo

@bob_zim @4censord @nixCraft Yeah, I get you.

This makes a lot more sense than drilling. Then maybe they can be resold or repurposed instead of just being wasteful.

12 March at 23:25 | Open on mastodon.social