ASPICRYP

                                     v0.3

                           (c) 1996 Cedric Reinartz


1. Disclaimer
-------------

               !!!  This software is "as it is"  !!!

The makers and developers of ASPICRYP make no representation, warranty,
assurance or inducement, express or implied, as to its adequacy, sufficiency 
or freedom from defect of any kind. Neither the makers or developers will
have any liability to any user resulting from the use of it nor are they
responsible for any data loss or computer failure resulting from any inherent
incompatibilities with any other software or hardware.


2. Introduction
---------------
ASPICRYP is a DOS based TSR which hooks to an ASPI-Manager and encrypts the
data going to a SCSI-device using the BLOWFISH algorithm in CBC-Mode. 
You have to specify a password on the commandline which must have (for security
reasons) at least 4 characters (8 or more are recommended).
The programm is hardcoded to encrypt all the data going to and to decrypt all
data comming from the SCSI-device 0:3:0 . 
In this way you can encrypt any SCSI-devices: Harddisks, CD-ROM, CD-Writer,
Tapedrives, MO, ... . Up to now I have only tested a (single) Tapedrive 
(HP1533A) with two different programms.
Since the encryption process is very fast, there is absolutely no delay when
using my Tapedrive (wich has a transfer rate of about 500kB/s) on a 486DX2/66
or higher.
Attention: After encryption the data can NOT be compressed by the SCSI-Device!
So use a backup programm which compress them prior to sending them to the
SCSI-device.

I'm interested in any feedback! If you have any questions, suggestions or
improvements, please leve me a mail.


3. Changeing the parameters
---------------------------
I'm sorry, but there is no programm (up to now) which does the job for you.
If you are capable of using a HEX-Editor you can change the hardcoded
parameters using this structure:

       Length Default   Remark
       --------------------------------------------------------------
  Byte  00  Logical Unit Number (LUN)
  Byte  03  Target ID
  Byte  00  Hostadapter Nr
  Byte  00  00 -> parameters for device 1 are valid

  Byte  FF  Logical Unit Number (LUN)
  Byte  FF  Target ID
  Byte  FF  Hostadapter Nr
  Byte  FF  FF -> parameters for device 2 are not valid

  Word    relative Pointer to the text which is shown at
                        initialisation: " 0:3:0           "
                        (You should patch this text also)

  Byte  0ah,"ASPICRYP v"        ! this part will never change !

Search for the beginning of the copyright message and go backwards.
This structure will be the same in future versions. 
For v0.3 it starts at 1DC9 Hex.

YES you can encrypt two devices at a time (with the same password ofcourse).
But: I never tested this.


4. Technical Notes
------------------
This software needs at least:
  -  IBM compatible AT-system with an 80386sx processor or better
  -  DOS 3.0 or above
  -  10kB of free DOS-RAM (you can load it high)
  -  ASPI-Manager installed

Speed:    1.8 MB/s on a Pentium 90
          2.7 MB/s on a Pentium 133

Limitations:
Command posting is not supported by ASPICRYP (yet). So, before decryption
(and returning to the main programm) ASPICRYP waits until it has all the
data from the SCSI-device. This may slowdown the main programm.


5. Copyrights
-------------
BLOWFISH is a data encryption algorithm which was published in the Dr.Dobb's 
Journal magazine, issue #213 on April 1994. It was developped by Bruce Schneier
and is unpatented and placed in the public domain.
In the September issue 1995 of DDJ Blowfish was (after a sponsored contest) 
still unbreaked.
The advantages of this encryption algorithm is its design for 32bit CPUs like 
the 80386 and above.

The Blowfish IMPLEMANTATION used in this software was done by:

               Markus Hahn
               Schellingstrasse 13
               72622 Nuertingen
               GERMANY
               E-Mail: 681614@pcmail.rz.fht-esslingen.de

and

               Cedric Reinartz
               Schumannstrasse 51
               40822 Mettmann
               Germany
               E-Mail: cer@servww4.ww.uni-erlangen.de (till end of 1996)


ASPICRYP v0.3 was done by Cedric Reinartz. It can be distributed freely if:

   - both (the programm and this manual) are distributed together
   - both are unmodified
   - no fee (excluding material and shipping costs) is taken

If you use ASPICRYP v0.3 for your own private purpose, you can do so 
without paying any money (to me or someone else). But:

          You have to send me a note that you are using it!

For any non private use you have to contact Cedric Reinartz.


6. History
----------
v0.1  Internal version, not released
v0.2  1st released Version
v0.3  Bug removed: ASPICRYP corrupts other programms which uses
                     386 code. (I used PUSHA and therefore corrupted
                     EAX, now it's PUSHAD).
        Hex-Patch Description corrected.


7. Future
---------
 - possibility to remove ASPICRYP from memory
 - API, so other programms can control the behaviour of ASPICRYP
 - possibility to reconfigure ASPICRYP at runtime
 - possibility to chain ASPICRYP with other driver (so you can
   load more than one ASPICRYP if you have different devices
   with different passwords)
 - Configuration programm (so you don't need to Hex-patch)