Dextor 2.0 © Msi Software 1997 - All Rights Reserved!
DEX-II "Dynamical Encoded Xor scheme 2" Encryption

For Amiga OS 2.x/3.x, cli/shell only.
Created in Norway in a city know as Trondheim.

Features!
o 1 to 256 character password
  32bit based compression (very compression on 32bit cpu+ram machines)
  This gives you 8 to 2048 bit encryption (128 to 8192 bits actually :-)
o Fast, fast, fast :-)
o It's gives good encryption
o It's small (did I mention fast?)
o The password is NOT stored in the file (it would be stupid :-)
o The encryption level is stored in the file
  so you only need to remember the password :-)
o I use it myself :-)
o It works as expected :-)
o Takes less than 3 seconds to encrypt a 2MB file (I said it was fast :-)

----------------------------------------------------------------------------
Shell Usage: Dextor <filename> <key> [<level>] [<new>]

filename - the name of the file to encrypt/decrypt
     key - the password key to encrypt/decrypt with (max 256 characters)
   level - optional, can be 1,2,3,4,5,6,7,8,9 (1 is default)
     new - optional, if this switch is used a new file will be made
           for the encrypted data, saved with .DEX at the end.
           (if an encrypted file have .DEX at the end of the name
            it will be removed before saving)

----------------------------------------------------------------------------
History:

v1.0 - 23.Jun.1997
       First release!

v2.0 - 17.Nov.1997 (Major release!)
       Rewrote the program, DEX-I no longer supported. (not good enough :-)

----------------------------------------------------------------------------
Please note that the key is not stored in the encrypted file,
so if you forget it you are stuck forever :-)

Please note that Dextor currently do not allow encrypting
an already encrypted file.

Dextor will store the encryption level in the
encrypted file, so there is no need to have to remember
what level you used for encryption.
You just worry about remembering that key :-)

Please note that Dextor will replace the original file,
(it will use the same name).
If you want to make it easier to recognize files made by Dextor,
please use the extension ".DEX" (add it to the end of the name).
The NEW switch will tell Dextor to add .DEX to the encrypted file.
Dextor will ignore the extension when loading a file.
And if .DEX is at the end of the filename it will be removed when saving,
unless the NEW switch is used (will only work when encrypting)

Please note that files are loading directly into memory,
so make sure you have enough memory for very larger files.

Dextor is not ment to compete with high level
encryption schemes like PGP. Dextor is intended as a simple,
small and effective "Home Encryption Tool".

----------------------------------------------------------------------------
DEX-II Encryption Levels:

Level 1 - Very good (and very fast) encryption! (this is the default level)

Level 2-9 is not implemented yet, and thus not available.

----------------------------------------------------------------------------
Encryption information:

For obvious reasons I can not reveal the actual encryption scheme :-)

But for those interested, quickly calculated DEX-II
is capable of 32bit based encryption from a key of 128 bits to 8192 bits.
The reason it is 32bit (4 characters) based, rather than 8bit (1 character)
is to speed up encryption on machines with a 68020 or better CPU
and some 32bit fastram, check out the speed test further down.

The number of key bits depend on the length of the password,
longer passwords give more bits and better encryption,
but more bits will take longer to encrypt :-)

Those who live in countries with encryption laws (like USA) please check
if you are allowed to use this program, I think USA have a max 40 bits limit.
Think of each character in the password as 8 bits,
this means you can only use a password of max 5 characters :-(

----------------------------------------------------------------------------
Dextor 2.0 DEX-II scheme: Speed tests
System used: Amiga 1200HD, OS3.1, Blizzard 1230-IV/50MHz 68030 w/68882 FPU.
             ROM mapped to fastram, 16MB 60ns 32bit fastram.

The speed of Dextor do not change by the contents of a file,
nor is there any real difference between encrypting/decrypting.

Filesize: 353286
Password: Password

   Level: 1 = 1 second

For a 1MB file it would take around 1.5 seconds with level 1.
For a 2MB file it would take around 2.5 seconds with level 1.

A pretty nice speed really, compared to DEX-I
and some other compression utils :-)

----------------------------------------------------------------------------
Here is a tip:

Pack/Archive a file then encrypt it with Dextor.
or pack the file, encrypt it, then pack it again.
Packing it first will not only make the file smaller,
but Dextor will encrypt faster.
And it will be very hard trying to crack the encrypted file,
since there hardly is anything senssible in a LHA/LZX/XPK file etc.

Dextor is also usable from scripts etc.
It returns RC 5 (RC = return code) with user based errors,
and RC 10 at general errors,
and RC 20 at unknown errors.
RC 0 is returned if all went well.

Dextor can encrypt any binary files (meaning ALL files :-)
Why not try to archive more than one file,
or even a directory with LHA or LZX.
Then encrypt the resulting archive with Dextor :-)

----------------------------------------------------------------------------
IMPORTANT!

AND PLEASE TAKE GOOD CARE OF YOUR KEY,
IF YOU LOOSE IT (FORGET IT) YOU WILL BE UNABLE TO DECRYPT
THE FILE, AND ALSO MAKE SURE YOU CHOOSE AN EASY TO REMEMBER KEY
THAT IS UNNUSUAL AND NOT SO EASY TO GUESS.
Dextor IS ONLY AS SECURE AS YOUR KEY IS,
SO BE CAREFULL IF INTEDING TO GIVE SOMEONE A KEY FOR
SWAPPING OF SECRET ENCRYPTED FILES,
MAKE SURE NO-ONE IS ABLE TO SNAP UP THE KEY.

----------------------------------------------------------------------------
Disclaimer:

Use this program on your own risk,
I nor Msi Software or anyone else is responsible
if things go wrong. But if they do, please let us know
so we can fix any possible problems with this software.

----------------------------------------------------------------------------
Distribution:

Freely Distributable ShareWare
To pay the shareware fee, send me something nice via email,
or via normal (snail) mail.
Like perhaps a copy of your latest game or program,
or perhaps a cool picture/anim or module etc.

Please let me know before you send files larger than 1MB in size.
For Commercial/ShareWare/LicenseWare,
send me a free registered and complete copy of your product.
Updates to Dextor 2.x can be used freely,
and the license is a lifetime license.

A future Dextor 3.x will be free to registered Dextor 2.x owners,
unless stated otherwise in Dextor 3.x
Currently Dextor 3.x is maaaaany months away.

Right now, I want YOUR comments on Dextor, So email me know.
Dextor can be distributed freely as long as a nominal
copying fee is only charged.
Aminet and Amiga coverdisk CD's and Fred Fish,
have my permission to distribute Dextor.

----------------------------------------------------------------------------
Dextor was compiled with AmigaE v3.3a from Wouter van Oortmerssen.

Dextor is Copyright © Msi Software 1997
DEX-II encryption scheme is Copyright © Roger Hågensen 1997
Amiga is Copyright © Amiga International 1985-1997
AmigaE is Copyright © Wouter van Oortmerssen 1991-1997

----------------------------------------------------------------------------
Author: Roger Hågensen
        Kolstadflata 35B
        N-7078 SAUPSTAD
        Norway
   Tel: (+47) 72 59 07 35
 Email: Roger Hågensen <emsai@online.no>   Subject: Dextor 2.0
   WWW: http://home.sol.no/~msi/

$VER: Dextor.Txt 2.0 (17.11.1997) #TEXT © Msi Software