From: Mike Ingle <MIKEINGLE@delphi.com>
Date: Mon, 25 Oct 93 20:49:45 PDT
To: cypherpunks@toad.com
Subject: New Crypto Tool - Beta Testers Wanted
Message-ID: <01H4JPOM66M091XK6Q@delphi.com>
MIME-Version: 1.0
Content-Type: text/plain


I've been writing a new crypto tool called Secure Drive, and I need
people to help me test it. This is a program which encrypts hard
drive partitions and floppy drives, at the sector level, on the fly,
as you use them.

To use the program, you create a small partition, usually D:, big
enough to hold everything you want to keep private. Then you run
the utility CRYPTDSK to encrypt the partition using a passphrase.
Everything on the partition except the boot sector is encrypted, in
place, at the sector level. Your C: drive is not affected.

Then you load the tsr module, SECTSR, which takes only 2K of RAM.
Use LOGIN to enter your passphrase, and the D: drive becomes
accessible. All reads are decrypted on the fly, and all writes are
encrypted on the fly. When you turn off your computer, it is
automatically secure.

You can decrypt your partition at any time using CRYPTDSK.

You can also encrypt floppy disks using CRYPTDSK. You LOGIN /F and
enter the floppy password, and the floppy becomes accessible. You
can freely interchange encrypted and clear disks, as long as all of
the encrypted ones use the same passphrase. The TSR senses
encrypted disks and turns itself on and off automatically. If you
use different passphrases for different disks, you have to run
LOGIN /F again to change the passphrase in memory.

Floppies can also be decrypted. CRYPTDSK will not allow you to
decrypt with the wrong passphrase and scramble a disk.

You can have an encrypted hard drive partition and encrypted
floppies active simultaneously, using different passphrases.

The program uses Colin Plumb's very fast assembly language IDEA
code in CFB mode, and it uses MD5 to hash the passphrase. The disk
ID and sector number are used in the IV to make each sector unique.
Colin Plumb has also provided advice in writing the program.

To be a beta tester, you have to:

Live in the U.S., of course.

Agree not to export the program out of the U.S.

Please don't give out the beta version; it may be buggy. Source
code will be forthcoming as soon as I'm sure there aren't any
serious problems with the code.

Have two partitions or be willing to repartition your hard drive.
(There is supposedly a program to do this non-destructively, do you
know where to get it?)

Back up your hard drive. This program does sector-level I/O, and a
bug or interaction could easily scramble your hard drive.

Operation with DOS 6 and with two physical hard drives particularly
needs testing. I have DOS 5 and one hard drive, so I'm not sure if
it will work.

Use this program at your own risk! Back up everything.

If you want to help test the program, send me e-mail. State that
you agree not to export, and tell me if you want the files in
UUENCODE or PGP ascii armor (not encrypted) format.

There are more detailed docs with the program.

Send me all bug reports, problems, comments, suggestions, etc.

--- MikeIngle@delphi.com