Re: Breaking: Shuffle-based Provably Fair Implementations Can Cheat Players (proof)
Isn't it a bad implementation though? They generate the 30 initial numbers, without your client seed, and they can generate what ever they want, and you can't verify that they cheated with the inital generation. So while it is technically provably fair, because of how the initial shuffle is generated, they could create a higher house edge by predicting what the gambler likes to do (ie over 7) and generate the inital deck so it is more likely to get under 7?
Yeah, but still better than I thought.
Quote
They should just get rid of the initial generation and play with a fair deck (5 ones, 5 twos, 5 threes, e.t.c)
They can't do that either.Let us say, we have 5 of each. Each number appears once every six times.
It is shuffled and two numbers are selected.
Now the odds that the second number is "1" when the first number is "1" is less than the odds that the second number is "2" when the first number is "1". while it should be equal.
That is, if the first number is "x" there is only 4/30 chance that the second number is also "x". The probability should be 5/30.
I suggested this:
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Possible solution: (just a suggestion)
Two rolls are generated separately in the same process with the same server seed and a standard initial numbers that is the same for every roll.
First die inputs:
Standard initial numbers (6. 30 is good too) (I)
One server seed (S)
One client seeds (C1)
Second die inputs:
Standard initial numbers (6. 30 is good too) (I)
One server seed (S)
One client seeds (C2)
Process:
The same.
So it looks like this:
Time: 2016-06-07 22:28:37
Game:Over 7
Roll:6 - 5
Bet Amount. mBTC: 0.01227
Profit, mBTC: +0.01656
Server Seed:
0c1a6e80e45753bf1018eeee76eb3244
Initial Numbers:
[1, 2, 3, 4, 5, 6] (or 30 standard numbers, for example 1,2,3,4,5,6,1,2,3,....5,6 or 1,1,1,1,1,1,2,2,2,2,2,2,....6)
Initial Hash:
fb02ecd1a7814103bd718de5e21e6f21ca746cc9e36ec8d683bc7eb3b93acdd0
Next Hash:
232270e0092a9f4c52cbbade6fb4174f9f58878485d558a5d6f1f43c51da38bc
Client Seed (1):
0.2707008711765295
Final Numbers (1):
[6, 1, 4, 3, 2, 5] (.... for 30)
Client Seed (2):
0.2938293211765295
Final Numbers (2):
[5, 3, 2, 4, 1, 6] (.... for 30)
Two rolls are generated separately in the same process with the same server seed and a standard initial numbers that is the same for every roll.
First die inputs:
Standard initial numbers (6. 30 is good too) (I)
One server seed (S)
One client seeds (C1)
Second die inputs:
Standard initial numbers (6. 30 is good too) (I)
One server seed (S)
One client seeds (C2)
Process:
The same.
So it looks like this:
Time: 2016-06-07 22:28:37
Game:Over 7
Roll:6 - 5
Bet Amount. mBTC: 0.01227
Profit, mBTC: +0.01656
Server Seed:
0c1a6e80e45753bf1018eeee76eb3244
Initial Numbers:
[1, 2, 3, 4, 5, 6] (or 30 standard numbers, for example 1,2,3,4,5,6,1,2,3,....5,6 or 1,1,1,1,1,1,2,2,2,2,2,2,....6)
Initial Hash:
fb02ecd1a7814103bd718de5e21e6f21ca746cc9e36ec8d683bc7eb3b93acdd0
Next Hash:
232270e0092a9f4c52cbbade6fb4174f9f58878485d558a5d6f1f43c51da38bc
Client Seed (1):
0.2707008711765295
Final Numbers (1):
[6, 1, 4, 3, 2, 5] (.... for 30)
Client Seed (2):
0.2938293211765295
Final Numbers (2):
[5, 3, 2, 4, 1, 6] (.... for 30)