On Sat, 4 Jan 1997, Mike wrote:

> >And of course you'll want to support free and open research of all sorts
> >that attempts to crack such code protection, and hence the free
> >publication of the results of such work - because how else shall you know
> >which, if any, of the competing products is any good?
>
> Is this sarcasm - or real, still recovering from New Years drinks...

Well, I suppose it is a bit more sardonic than I had intended after all.
No, it's quite serious.  A point I've made before, often enough that I
felt it was time to try to find new words for it: that one thing the
history of all forms of crypotgraphy show very clearly is that relying on
keeping your algorithm secret is the best way to guarantee that the result
is far weaker than you'd hope.

> >'Cause how else are you gonna know?
>
> What about results, why would one need to decode the guts, we don't need
> to decode the structures of 74HC as against 74S we can compare the results !

I won't use those words anymore, since they seem to lead to a
misunderstanding.  We don't need to crack a 74x04, say, because it doesn't
claim to hide anything.  For an alleged code protection scheme, anything
that hasn't been tested by outside investigators is highly unlikely to be
half so secure as the manufacturer - or you - might wish.