From: mike@EGFABT.ORG (Mike Sherwood)
Date: Sat, 26 Mar 94 08:30:41 PST
To: Mikolaj Habryn <dichro@tartarus.uwa.edu.au>
Subject: Re: Digital Cash
In-Reply-To: <199403261512.XAA25558@lethe.uwa.edu.au>
Message-ID: <kq1sJc1w165w@EGFABT.ORG>
MIME-Version: 1.0
Content-Type: text/plain


Mikolaj Habryn <dichro@tartarus.uwa.edu.au> writes:

> 	Let me make a point here: I run an Amiga, and Amiga games do go 
> to town on copy protection. They generally rip the OS out of memory, and 
> install a custom one, do custom formats of the disk (as in the structure 
> is normally unreadable) and have further hard protection such as laser 
> holes, etc.
> 	This is not kids' stuff - this is serious, and these people are 
> carcking it within hours. Let them loose on any program with their own 
> hardware, and they are capable of doing some quite serious things to the 
> rights of the author.

Graham's point is still valid here.  cryptography is a matter of fairly 
complex mathematics - this is not a trivial thing to attack.  I know from 
experience many ways of getting around the various forms of copy 
protection used on software, and most of it is just a matter of comparing 
a legitimate run with an illegitimate run.  to oversimplify, there is 
often a point in a program that branches on a test condition and in many 
cases, all that needs to be done is to find these and change a a branch 
if equal instruction to branch if not equal, so that the program depends 
on *not* satisfying the parameters of the copy protection.  likewise, on 
serialized software, it's often fairly easy to figure out the pattern and 
change the serial number without figuring out the way it's encrypted by 
the program.  anyway, I digress, the purpose of this list is data 
encryption, not to teach people how to beak copy protection.  the only 
potential harm that could be done by these people is to weaken the 
programs we use for encryption, but there is not much of a point to doing 
so.

--
Mike Sherwood
internet: mike@EGFABT.ORG     uucp: ...!sgiblab!egfabt!mike