[Cryptography] Real-world crypto/PRNG problem: Bridge

[Thierry Moreau]

On 23/08/16 03:24 PM, Thierry Moreau (i.e. myself) wrote:

(same post, revised numbers due to a combinatorial counting error)

> On 22/08/16 02:20 PM, Salz, Rich wrote:
>
>> 2. They are using the same seed to generate enormous numbers of sets
>> of hands (76,000) at a time
>
> One random hand is a selection among 52! which is about 225 bits of
> entropy.

Read a selection among 52!/(4*13!) and 95 bits bits of entropy.

>
> Repeat this 76,000 times and you get roughly 17 million bits.
>

Read 7 million bits.

> Any single PRNG instance solution is going to trigger endless
> discussions among experts. The client organization/community
> (presumably) has little ability to select a good expert.
>
> Thus, this would be a good sell for the so-called "quantum" random
> number generators (actually based on an arrangement of single photon
> detector(s)).
>
> I.e. without millions of truly random bits, a typical client community
> participant would have hard time to acknowledge that while e.g. 75,995
> hands are deterministically dependent on the first 5, it does not
> matter. Computational independence is appealing to a significant portion
> of exerts, but not necessarily to a player/gamer.
>

Read 75,990 hands deterministically dependent on the first 10.

> - Thierry Moreau
> _______________________________________________
> The cryptography mailing list
> cryptography at metzdowd.com
> http://www.metzdowd.com/mailman/listinfo/cryptography