That's not true.  The best time will show is that you pay out on about half the bets you receive.  It won't prove that you don't tend to pay out on almost the bets your friends make and very few of the ones made by others.

Better proof of fairness would be to actually prove that you're being fair.  By allowing the player to pick a seed for the randomness (like almost every other reputable bitcoin gaming site out there does).

I think PrimeDice are more vulnerable to this kind of accusation than either Just-Dice or CoinRoll, because PrimeDice changes the server seed before every roll, whereas CoinRoll only changes it once per day, and Just-Dice never changes it unless the player requests that it be changed.

Not that I think PrimeDice is cheating anyone; I don't.  It's just harder to verify that they aren't - you would have to make a note of each individual server seed, which probably nobody is going to be prepared to do.

Very nice!  He got it on only his 8th "bet 1 BTC at low chance, high multiplier" attempt - then left for the day.  That's the way to do it!

It works similarly on all provably fair sites, pretty much.

1. the server picks a random "server seed"

2. the server shows the user a hash of the server seed

3. the player picks their own seed, the "client seed"

4. the server uses the server seed and the client seed to generate the outcome of the game

5. the server publishes the server seed

Notice that it's important that 1. comes before 3.  The player picks last, so there's no way the site can influence the rolls.

Once all five steps are complete, the player can check that:

a) the server seed published in step 5 does in fact hash to the string that was shown in step 2, and
b) the client seed (step 3) and server seed (step 5) do in fact generate the shuffle, roll, spin, or whatever that happened in the game (step 4)

That's all.  Some sites (satoshidice, coinroll) change the server seed every 24 hours.  Some sites (primedice, bitzino) change it every roll.  Some sites (just-dice) change it on demand.  I prefer the last way - 24 hours is a long time to wait to verify a suspicious roll, but changing the seed every roll makes for a lot of work for the player, making a note of each hash, verifying each seed, etc.

For Just-Dice, there's a user-contributed script at http://jsfiddle.net/Zq8tL/3/ which lets you tell it the client seed and server seed, and outputs all the rolls those seeds generate.  So you can check it against the rolls you actually saw and make sure there's nothing fishy going on.

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Edit on 28 Nov 2013: at the end of September 2013, from bet 145 million onwards, the algorithm used to generate rolls was changed and so the above-linked jsfiddle script no longer works.

There's a new verifier linked from the bottom of the 'Fair?' tab which is able to apply both the old and new algorithms, and defaults to the new one.
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This again?  I thought you already admitted that this isn't true, here:


And yet now you're claiming again that the single large bet is just as good as a martingale sequence.

My offer to bet about this still stands.

How were you picking high or low?  Was it random?  It looks like you need a "not" in there somewhere. 

My prediction: up and down. 

You can't edit posts on the auction forum I think.  Because then you could retract bids.

Bidding is always open.  The last ad didn't go up until 3rd so the next one will go up on 10th.

There was only one bid last week, so I let him put the ad up for free. 


I think you're different enough, probably, maybe.  It's a close call, and I reserve the right to change my mind for future weeks, but this week it's OK.  I'd consider Seals to be different enough.  I don't see poker competing with dice games.  The only reason I consider BitVegas to be different is that it's so opposite to JD.  You have a pretty 3D environment and high house edge, whereas JD has a very plain site and a low house edge.  I would expect the two to attract different crowds.

And so to make $30k/year with all your assumptions, you would need to invest 6455/12 = 538 BTC?

I'm finally out of SDICE.  Sold yesterday.  Lost 70% of investment. 

Hopefully now the coins are in Just-Dice I'll make up the losses.

Not if everybody takes out their profits.

Per month?

You also seem to be assuming there's only one month in a year.  Most years have more than that.  Or are you trying to earn $30k per month?

Presumably because you would still need to reverse the address hash to find out the public key for that address, whereas the cold wallet has made several spends already and so its public key is - uh - public?

If you look at the 'betid' column, you will see that there are usually many more than one bet per second.  The site streams results live to everyone who is currently connected, and to save bandwidth I only stream one bet per second unless the bets are of significant size.  Every bet of 0.01 BTC or more is streamed no matter how fast they happen.  But "dust" bets aren't shown, other than one per second to keep the display ticking over.

There are no site bots.  There are customer bots though, running their mini-martingle bets over and over.  They eat away at the site profits, satoshi-by-satoshi.  And then they lose it all back.  It's fun.

I didn't know what you were suggesting, and considered that you were just posting a "wow, look at my sucky luck" picture.

But then I considered that others would see it and think "wow, they cheated you!", so I followed up with a luke-warm proof that it was fair.  Since you hadn't yet changed your seed, I can't publish the secret for people to verify the sequence for themselves (or you'd see what your next rolls are going to be, and I expect your luck would rapidly improve!)

If I was going to invest the cold wallet coins somewhere, I think I would have to invest them in Just-Dice.  I know they're safe from theft there.

But that halves everyone else's profits and vastly increases my risk of ruin.  It would be as if every investor was risking 2% of their investment per roll, and giving half their profits to me.

I can achieve the same effect with no risk by increasing the commission to 50%.  The investors still lose half their profit, but the max bet isn't dangerously inflated.

Unlucky.  But provably fair:

That's a strange way of putting it.  I don't see it as "my money" and it strike me as odd that you do.