Encrypted Drives

[Robert B. Carleton]

I've been experimenting with encrypting drives with bioctl(8). The idea 
is to be able to "shred" a drive once I've finished using it for a 
particular purpose. Rather than using a keydisk, I'm experimenting with 
using the a and d partitions of the same drive, a partition being 1MB, 
and the d partition, using the rest of the disk space.

The risk of the a partition being read during normal operation is 
accepted in this case. If the drive becomes unreadable for some reason, 
the data would be retrieved from backups.

Would overwriting the a partition be sufficient to make the data in the 
d partition unusable? Maybe dd /dev/urandom over the a partition three 
times? This isn't for the system disk, but other external disks.

TIA,

            --Bruce