Re: What the NSA is patenting

At 12:18 AM 9/7/96 -0800, Adamsc wrote:
>On Fri, 06 Sep 1996 11:59:18 -0500, John Deters wrote:
>
>>I hope some hardware hacker who knows their low-level stuff will be able to
>>write a secure disk wiper.
>
>They have: it's called a bulk tape eraser. <g>
>
>
>I'd just store everything sensitive on a floppy. Those are easy to erase with a
>heavy duty magnet (not a wimpy refrigerator magnet).  I understand slagging one
>in the microwave is also effective <g>.

Just remember that an AC-driven bulk eraser will be far more effective than 
a permanent magnet at erasing data securely.  An oscillating magnet field 
re-magnetizes the floppy 120 times per second, as opposed to the single 
magnetization done by  the permanent magnet.  Each pass through the 
hysteresis curve brings down residual signals somewhat, maybe 10 db.  With 
the AC field, it's hard NOT to have a good erase.

Jim Bell
jimbell@pacifier.com

Burning the floppy would seem to solve the problem.  Lock sensitive
data in RAM away from disks except for burnable floppies.  I guess
linux can be configured to keep sensitive data in a RAM filesystem,
keeping it from being synced or flushed.

> 
> Burning the floppy would seem to solve the problem.  Lock sensitive
> data in RAM away from disks except for burnable floppies.  I guess
> linux can be configured to keep sensitive data in a RAM filesystem,
> keeping it from being synced or flushed.
> 

Currently, I am hacking up a prototype of an armored keysigning box using
an old 386.

This box signs/decodes incoming E-mail as long as the key switch is in the
correct position.  The key remains in /dev/ram0, and is encrypted, as well
as stored in a .au file.  For one of the keys, I am using a hacked des
program that reads a file off a floppy for the TDES key before copying the
PGP key into the ramdrive.

What I plan to do is write software so that multiple floppies are needed
to load the key into the RAM filesystem, and to "lock" the machine.

After the key is loaded, all network daemons are killed except smail, and
all gettys are killed.  This makes it hard for someone locally to get to
the RAM drive.  If the box is rebooted, or turned off -- bye bye RAM
drive.