Re: Cracks/Key Generators

From: Walter Roberson (roberson_at_ibd.nrc-cnrc.gc.ca)
Date: 10/20/04 

Date: 20 Oct 2004 06:55:50 GMT

In article <547d92f1.0410192201.7b98af71@posting.google.com>,
karan <karan@iitk.ac.in> wrote:
:How does one make a crack/Keygenerator?
:How do they work?
:How can a software key - check be made fool proof?

The only way to make a software key-check "fool proof" is to use
a one-time-pad to encrypt the program, with the pad being at least
as large as the program itself, and the one-time-pad being discarded
after a single use, thus requiring a new copy of the program
for every invocation. Every other mechanism can be broken,
by brute force if necessary.

Note that I am making the assumption here that when you say
"fool proof" that you mean that it is literally impossible to
bypass the control mechanisms without having been given the
key.

I am also making the assumption that the Universe will
last indefinitely long in a form that permits computations to
proceed.

Furthermore I am assuming that the program is not so long
as to require every possible storage state in the Universe.
And even if it does occupy every possible storage state,
I wouldn't want to promise that the program would be impossible
to break, as there's probably a way to do computation using
virtual particles as temporary storage -- I don't recall scientists
having found any limit on the number of virtual particles that
can exist simultaneously.

Now, if you'd been willing to settle for a software check that would
only take on average 100 or so trillion years to break, then my
would have been rather different. Most people would be satisfied
if their protection mechanism would probably last until Sol went
nova and expanded to be large enough that Terra's current orbit would
lie within the solar atmosphere. But such protection could not be
called "fool proof", merely "somewhat fool-resistant." 

-- 
Feep if you love VT-52's.