decrypt first or just secure erase it?

[digityzed]

I'm repurposing a computer that has sensitive data so I need to secure erase it. The hard drive is encrypted by TrueCrypt. I started decrypting it, but TrueCrypt is saying it's going to take 4 hours. I'm impatient. Can I skip decrypting and just secure erase it or is decrypting necessary?

P.S. - I don't want the drive encrypted in it's next iteration.

 

[qazzi]

well since it encrypted already you can secure erase it. even if they manage to undelete it. they need to decrypt it which will probably take more time.

 

[dr-claw]

One thing I like to do is boot off of Linux and use its badblocks command to completely wipe a disk (and as an added bonus, it checks thoroughly for bad blocks on the disk).

The command is:

badblocks -sw /dev/sdX

where you replace /dev/sdX with the device you want to wipe out. WARNING: This command will IRREPLACEABLE ERASE the drive you use it on, including all partitions and the partition table. If you accidentally point it at the wrong drive, it will erase that drive instead. MAKE SURE YOU HAVE BACKUPS!

Also, this command can take quite a while to complete, like a couple of days or so for a large drive or on slow hardware, so make sure you're prepared to leave the computer running for a few days straight.

You can get a list of disks and partitions with the command:

fdisk -l