From: Cory <cory4321@yahoo.com>
Date: Sun, 26 Jul 1998 21:42:14 -0700 (PDT)
To: cypherpunks@toad.com
Subject: Re: enc....
Message-ID: <19980727043530.4083.rocketmail@send1d.yahoomail.com>
MIME-Version: 1.0
Content-Type: text/plain





"Bernardo B. Terrado"  wrote:
 
> A virus uses encryption to hide itself (correct?),
> but will the files in a pc be safe from virus when encrypted? why?


a virus can be encrypted or it could leave itself open. usaually the
first.

it all depends on the combination of what virus and encryption
software you use.
Many times a virus will infect by waiting for you to open a file (run,
copy, move)
when it sees a file open it will add itself to the end and then move
the start
of the program to the virus.  When the program is executed it jumps to
the virus who loads itself
into memory and then jumps seamlessly to the beginning of the program,
unperceptibly( if done right)

If your files are encrypted by a program that stays in memory and lets
programs run like normal a virus will run like
normal.  If you have an uninfected file PGPed when you extract a copy
it will become infected like a normal file
however the pgp file will not be infected.  If the encryption is built
into the program and has a checksum 
you will be notified if it is infected but if it just runs a
decryption routine and then starts the program then it 
could be infected before the decryption routine.

in general if you can read/write a file so can a virus.

If you are worried about infection, get an uninfected copy and
make a detached pgp .sig  then run it on your computer in a batch file
so
pgp checks the signature before it runs.  if pgp fails the sig. your
program is infected
each virus is unique and acts differently, remember they are just
written  like normal programs.
If you are indepth interested, search for a virus authors page. 
Anti-virus people are vague so
you don't figure out how to make one but a virus author will probably
have guides on how to make
a virus.  This gives you intimate knowledge of a virus's abilities.
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