[Cryptography] quantum computers & crypto

Ray Dillinger bear at sonic.net
Fri Nov 12 17:18:02 EST 2021

On 11/10/21 10:37 PM, Bill Frantz wrote:
> On 11/10/21 at 1:59 AM, cryptography at dukhovni.org (Viktor Dukhovni)
> wrote:
>> Although of course in either case the number of permutations
>> of the deck in the orbit of the shuffle is rather small,
>> both 8 and 52 are a lot less than 52 factorial.
> Also, if you are trying to properly mix the cards for a game, a
> "perfect shuffle" isn't what you want. An interesting historical note
> is that when high-level duplicate games went from hand shuffling to
> machine shuffling, the hands showed a broader range of distributions.
> It goes to show that 3 or 4 "imperfect" shuffles don't result in good
> mixing.

The "unbiased shuffle" or "anti-sort" requires a source of randomness.

in fact where 'randroll' means a random integer from 0 to argument-1,
the unbiased shuffle is

for (card = 0; card < decksize-1; card++) deck.swap(card,

Sadly there is no very easy method to do this by hand, especially as
decks grow larger.


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