From: Erik.Lindano@ofa123.fidonet.org
Newsgroups: sci.crypt
Subject: New Encryption - a Challenge
X-Sender: newtout 0.02 Nov 17 1992
Date: 18 Nov 92  21:40:12

Larry Loen's lengthy last-try post discloses several unwarranted 
 assumptions.  Let me try to clarify some of them, and see if I get 
 through to him this time.
 
 > ...and asks us to test it by pressing the button in the various 
 > expert ways we know how and seeing if it doesn't jump.  If it 
 > does not, the experiment is a failure.  One box that fails is 
 > probably enough to decide it is no good.  
 
 Yes, but the thing that gets decided is whether the box withstood 
 that particular attack and whether the particular attacker could or
 could not open the box. No one assumed otherwise, nor is there any 
 indication (from me, at least!) that it was otherwise assumed. Since 
 the attackers are not amateurs but professional attackers, it *was*
 assumed (or hoped!) that the quality of their attacks would be
 much better than an attack made by a member of the general public.
 
 > If we fail, the box is good.
 
 It would be good against that particular attack of that particular
 attacker. Unfortunately, some attackers seem more willing to write 
 long philosophical ramblings than to attack.
 
 > On the other hand, I may be in ignorance of quantum mechanics, 
 > which may provide that the box will someday jump a foot in the 
 > air.  I may also be unaware that someone with just the right kind 
 > of compressed air gadget can make the box jump.  
 
 Logical fallacy of the purest kind, similar to the idea that 
 "retransmitting" encrypted data has anything to do with decryption.
 It does not, just as using compressed air is not the same as
 pressing the button on the box. The challenge was to *decrypt*, not
 to steal, buy or beg the solution. Either you can decrypt ONE 
 encrypted WORD among thousands or you can't. If you can, that fact 
 says something, both about the encryption and about your attack. If 
 you cannot, that fact also says something about both.
 
 It was not my intention to pass upon the quality of anyone's 
 prospective attacks - that was being left up to you. But I can see 
 now that failure may seem intolerable to a person with a very large 
 ego, to the point that the person may actually refuse the challenge 
 for fear of failure. This is auto-paralysis of the worst kind and I 
 just wonder if it may not be the reason for so much philosophizing 
 and so little decrypting.
 
 > But, it might be that, unknown to the inventor, a spring was 
 > accidentally slipped under the box.  It wasn't _supposed_ to be 
 > there, but it is.  The inventor goofed, unknowingly.
 > Now, if the testers are not allowed to look under the box, they 
 > may or may not come up with test techniques that uncover the flaw.  
 
 I guess that would depend on whether they are really proficient 
 testers. Proficient testers are not naive, tend to anticipate such 
 unexpected things, and do very well at anticipating them.  If they 
 can't do that, then they could not be distinguished from members of 
 the general public.
 
 > Or, maybe because the testers don't get to see the underside of 
 > the box, they fail to design a compressed air gadget that makes 
 > the box jump.  The opponent, however, has no such scruples and 
 > does look under the box and is thereby able to design a workable 
 > device.
 
 Maybe. But those are the conditions of the challenge. Personally,
 I think an astute cryptanalyst must have a great many insights
 and be able to anticipate a great many traps and weaknesses, or
 s/he cannot be a very good cryptanalyst.  To be sure, so will the
 "enemy". But no one has asked you to guarantee that the algorithm 
 cannot be broken by anyone else, only to try and break it.  
 Can you?
 
                                     (continues next message)
 

--- Maximus 2.00