Newsgroups: comp.os.msdos.misc
Path: utzoo!utgpu!watserv1!watmath!att!cbfsb!cbnewsc!tjr
From: tjr@cbnewsc.att.com (thomas.j.roberts)
Subject: Re: File protection in MS-DOS
Organization: AT&T Bell Laboratories
Date: Thu, 29 Nov 90 21:30:50 GMT
Message-ID: <1990Nov29.213050.26680@cbnewsc.att.com>
References: <1990Nov29.184157.25548@maverick.ksu.ksu.edu>
Lines: 58

From article <1990Nov29.184157.25548@maverick.ksu.ksu.edu>, by devolder@matt.ksu.ksu.edu (Eric DeVolder):
> In article <6@curano.acadch.com> rudolf@curano.acadch.com (Rudolf Kuenzli) writes:
>>In article <3920@male.EBay.Sun.COM> briantr@sunnet.EBay.Sun.COM (Brian Tran) writes:
>>>Hi there,
>>>
>>> We have a Wyse386 which are being shared by other users.
>>>
>>> Unfortunately, I have other private programs/data that I don't
>>> want other users to read or delete.
>>>
>>> How can I protect my directory in MS-DOS (mine is 3.3) ?
>>>
>>>Thanks, 
>>>brian
>>
>>Try with 'Secret-Disk' from Lattice. It will take a part of your hard
>>disk partition (you will decide how much) and create a logical
>>partition. The whole partition will be encrypted that means empty tracks
>>too. If you have let's say a drive C: before, you will have
>>addtionnallyy a drive D:. You may turn on/off that disk as you like.
>>Turning on the disk means that you will have to enter the passsword you
>>did use for the encyption of the partition. There is a resident module
>>load from 'config.sys' when you boot the system. You may work on your
>>secret drive like on a normal drive.
>>I am using 'Secret Disk' for years now and don't have one complaint.
>>
>>Rudolf

BEWARE! If someone really wants your data, Secret-Disk can be broken
easily by a knowledgeable person (I evaluated it for possible use,
but abandoned it after I broke its protection in less than an hour). 

Strong computer security is a difficult problem - the Department of Defense
Computer Security Center has levels of trust for computer systems, but
NO useful systems have been evaluated at the higher levels of trust
(B2 and up). In particular, PCs have special problems because of their
usual lack of physical security. IT IS IMPOSSIBLE TO HAVE STRONG COMPUTER
SECURITY WITHOUT EQUALLY STRONG PHYSICAL SECURITY. It may not be necessary
to lock up the entire PC, but some PHYSICAL device must be locked up
in order to obtain strong security. In this sense, Secret-Disk is
attempting the impossible, and predictably fails.

	For many users, programs such as Secret-Disk may be sufficient,
	for those of us interested in the theoretical aspects of computer
	security, and those interested in REAL security, such naive
	approaches are a joke. Beware, however, of approaches which
	seem to provide security, but in fact don't.

To repeat: ANY SECURITY SYSTEM WHICH DOES NOT HAVE A PHYSICAL DEVICE
UNDER PHYSICAL PROTECTION CANNOT PROVIDE REAL SECURITY. The usual
approach is to use PCs with only removeable media, and to lock them
up when not in use, and to keep the (media-less) PC in a controlled
environment where nobody can change EPROMs or other hardware
without being observed. For many users, such efforts are not
warranted.

Tom Roberts
att!ihlpl!tjrob  TJROB@IHLPL.ATT.COM