Re: SSD erase question

Personally I would use dc3dd from ports and you'll be plenty alright.

While dd would be enough in most occasions I won't assume your data is of a typical user. It only writes the random bits to the disk once. In some scenarios it's possible to reverse that. dc3dd takes care of that by writing multiple times.

There is also dcfldd which was superseded by dc3dd.

-- 
 J. Hellenthal

The fact that there's a highway to Hell but only a stairway to Heaven says a lot about anticipated traffic volume.

> On Mar 21, 2022, at 07:15, Damian Weber <dweber@htwsaar.de> wrote:
> 
> 
> Hi all,
> 
> I'd like to have an answer on a secure FreeBSD way to erase 
> SSDs before giving these away to someone for reusing it. 
> 
> Is the following enough to protect confidential data 
> previously stored there?
> 
> 1)  dd : overwriting with random bits (complete capacity)
> 2)  gpart create
> 3)  gpart add
> 4)  newfs
> 
> Details for an example with /dev/ada1 see below.
> 
> Thanks a lot,
> 
>   Damian
> 
> 
> # fdisk ada1
> ******* Working on device /dev/ada1 *******
> parameters extracted from in-core disklabel are:
> cylinders=484521 heads=16 sectors/track=63 (1008 blks/cyl)
> 
> Figures below won't work with BIOS for partitions not in cyl 1
> parameters to be used for BIOS calculations are:
> cylinders=484521 heads=16 sectors/track=63 (1008 blks/cyl)
> 
> Media sector size is 512
> Warning: BIOS sector numbering starts with sector 1
> Information from DOS bootblock is:
> The data for partition 1 is:
> sysid 238 (0xee),(EFI GPT)
>    start 1, size 488397167 (238475 Meg), flag 0
>        beg: cyl 0/ head 0/ sector 2;
>        end: cyl 1023/ head 255/ sector 63
> The data for partition 2 is:
> <UNUSED>
> The data for partition 3 is:
> <UNUSED>
> The data for partition 4 is:
> <UNUSED>
> 
> # gpart show ada1
> =>       40  488397088  ada1  GPT  (233G)
>         40       1024     1  freebsd-boot  (512K)
>       1064  480246784     2  freebsd-ufs  [bootme]  (229G)
>  480247848    8149280     3  freebsd-swap  (3.9G)
> 
> # dd if=/dev/random of=/dev/ada1 bs=512 count=488397088
> 
> # gpart create -s gpt ada1
> 
> # gpart add -t freebsd-ufs ada1
> 
> # newfs -U /dev/ada1p1
> 
>