On Wed, 9 Jun 1999, Alan Kennington wrote:
> Aaron,
>
> Are you assuming that it is impossible to do a core dump
> of a running process?
> I suppose that this is an advantage of a non-multiprocessing system
> -- at least there can be only 1 _user_ process at most.
see below.
> Then I guess you just have to write a different executable for
> each palmtop, and encrypt it -- but if you have a small
> piece of software which loads the encrypted portion of the
> program, then users can just run that decryption program
> themselves anyway.
>
> I still can't see how this would be invulnerable.
what i am seeing is that you compile the program as per
normal.. then write another program which breaks it up,
and loads it dynamically..
since the loader program is the key.. they need to decompile
the loader first - but if they modify it.. they also modify
the key to decrypt the real program..
hence it wont dynamically "decrypt" the file correctly - and
probably trash their palm - their own bad luck.
good old C programming tricks.. jumping to a memory
chunk and executing it.. you are going to be executing
memory.. (not functions)..
in theory.. it should work.
implementation is always the hard bit :P
cheers.
az.
--
Aaron Ardiri
Lecturer http://www.hig.se/~ardiri/
University-College i G�vle mailto:[EMAIL PROTECTED]
SE 801 76 G�vle SWEDEN
Tel: +46 26 64 87 38 Fax: +46 26 64 87 88
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