Re: Duplicating without duplimate

Mark Brader <msb@[EMAIL PROTECTED]
> wrote:
> Matthew Johnson writes:
>> ... The duplicating program then generates two pseudo-random
permutations
>> which individually reveal nothing about the desired hand, but when
>> applied in order, starting from a sorted deck of cards, but when
applied
>> in order produce the desired hand.
> 
> Neat idea!  It's sort of like public-key encryption.
> 
>> ... most of the time [it] gives the correct result, although
>> occasionally people screw up ...
> 
> To avoid this problem, you could additionally print a set of curtain
> cards

It can do curtain cards, the problem is that when two players say 'I
have one card wrong', and you swap them, it's pretty obvious who has the
other card now.

What we actually do is that I check against a copy of the hand records
after playing each board. This allows for error detection.,but not
recovery.

Matt