[Edit 5: Final update]

Edit 5: Final update

The issue was recognized by the Fortunejack yesterday. Today around 11:45 UTC a new update was pushed
Hence the off-by-one error resolved.
Screenshot of the confirmation: https://imgur.com/a/mgH5Pzo
I checked the roll numbers and everything looks perfect.

I was also given a bug bounty when i asked for it.
So i guess the case is closed. I will still keep it open for any further discussions and questions



So i was checking out the payout numbers in the Dice game of FortuneJack. I spotted something wrong

Normally in a dice rolls you have numbers between 0 to 99.99 resulting in a total of 10000 numbers.
But Fortunejack seems to be invalidating roll 00.00 making it only 9999 numbers. Even the FAQ section of their dice says "The roll numbers between 0 and 99.99 ..."

So i am going to take example of Primedice here

For a 2x payout

In primedice, we have Roll under 49.50 (0 to 49.49 giving 4950 numbers) and Roll over 50.49 (50.50 to 99.99 giving 4950 numbers)
In fortunejack, we have Roll under 49.50 (00.01 to 49.49 giving 4949 number) and Roll over 50.50 (50.51 to 99.99 giving 4949 numbers)

For a 990x payout

In primedice, we have Roll under 0.10 (0 to 0.09 giving 10 numbers) and Roll over 99.89 (99.90 to 99.99 giving 10 numbers)
In fortunejack, we have Roll under 0.10 (00.01 to 0.09 giving 9 numbers) and Roll over 99.90 (99.91 to 99.99 giving 9 numbers)

Fortunejack calls it 0.1% win chance but technically it's 0.09%


FortuneJack

If you bet 10 satoshi 9999 times (0 is not counted) at 990x payout on FJ, you are to lose 9990 times and win 9 times.
Total bet amount = 10 * 9999 = 99990 satoshi
Total Win amount = 9 * 9900 = 89100 satoshi
Total lose amount = 99990 - 89100 = 10890 satoshi

Total fee = 10890/99990 = 10.89 %

PrimeDice

If you bet 10 satoshi 10000 times at 990x payout on PD, you are to lose 9990 times and win 10 times
Total bet amount = 10 * 10000 = 100000 satoshi
Total win amount = 10 * 9900 = 99000 satoshi
Total lose amount = 100000 - 99000 = 1000 satoshi

Total fee = 1000/100000 = 1 %


I even asked FortuneJack about this issue this was their reply : https://imgur.com/a/W9Qwz9I


Edit : For a 10x payout the fee goes to 1.09% while they promise a house edge of 1%


Edit2 : It looks like they have had this problem since they started : https://www.youtube.com/watch?v=Slh4k8yM11o


Edit3: This is a 4 years old video on youtube which concerns this issue : https://www.youtube.com/watch?v=jwtLPWjVxYI
The guy is using 6x payout for Roll over 83.50 But it should actually be 83.49


Edit4: Update

It looks like their support guy wasn't looking very hard. Here are they apologizing about miscommunication : https://imgur.com/a/NAqLzrr
So 0 is counted. Of course i didn't just believe it but verified myself by running a script in the All bets page.

Now that we have 10000 possible numbers instead of 9999, We got a different problem
Fortunejack dice gives different Win chance for Roll under and Roll over.

For a 2x payout
In fortunejack, we have Roll under 49.50 (00.00 to 49.49 giving 4950 number) and Roll over 50.50 (50.51 to 99.99 giving 4949 numbers)

For a 990x payout
In fortunejack, we have Roll under 0.10 (00.00 to 0.09 giving 10 numbers) and Roll over 99.90 (99.91 to 99.99 giving 9 numbers)

So if i were to bet on FJ Dice, i would have a correct winning chance for Roll under but incorrect winning chance if i decided to go with Roll over
Not to mention the outrageous fee of up to 10.891% for Roll over

Here i am mentioning the concern : https://imgur.com/a/7xaFPtS
The issue is now under Investigation : https://imgur.com/a/rllgfZq

What boggles me is nobody care to notice this issue. FJ benefited from it for all these years and the users were mislead by an incorrect information.