Topic: bitZino - Bitcoin Casino - Blackjack, Roulette, 3 Card Poker, Slots and more! - page 40. (Read 82361 times)

And don't forget that timing me out because I've been sat half-way through a hand for 15-minutes should log me out, but leave me in the same place when I log back in.  


Sometimes when I reload a page that made a POST request, it re-makes the POST request.  Is it only when the POST times out that the reload does a GET?

Good suggestions! I went ahead and made this change for all the outcome messages. I agree that it is much more clear.

Yes - I think a simple colon after each of the 5 result words would be better.

Win: +2
Blackjack: +3
etc.

It should probably read more like "Lose: -2" he wants to tell that hand is a losing hand and the amount taken from your balance.

Good call! This would be really good for users that play with a lot of BTC, and want some extra security. We are also likely going to add 2-factor auth, and email confirmations for all withdrawals in the near future.


We are fully resilient to internet timeouts. All actions you take on bitZino are atomic. If your internet connection dies right as you hit the "Bet" button - your action will either make it to our servers or not. If it does, then next time you reload the page you'll see the table as if you had made a bet. If the action doesn't make it to our servers, then next time you reload, you'll see the table as if you hadn't made a bet.

We also keep tables around pretty much indefinitely - so if your internet connection dies mid-bet while you're about to go on a 3 day vacation, you can come back 3 days later and see your table exactly as you left it.


Ah - this is because your connection died while it was making a POST request to /table_transfer. And, now that you're trying to reload hte page, it is doing a GET request to /table_transfer, which isn't implemented. I will implement the GET request for this action so that it just does a redirect back to the table.

Regardless of the Not Found error though - your game should still be in a non-corrupt state. Either our server received the POST to /table_trasnfer, and you got bought-in, or it didn't see the request, and you didn't get bought in. If you just go back to the main page at https://bitzino.com/blackjack, you'll be able to see what state the table is in.

Probably a silly point, but "lose -2" reads strangely.  If I lose -2, don't I win +2?

Funnily enough, my Internet just went down.  While it was down, I clicked 'buy in', and eventually got an error page from Chromium.  When the connection came back, I refreshed the page, and got:


The browser's address bar is now showing https://bitzino.com/table_transfer rather than the usual address, but I didn't change it.

(So I guess that answers my question!)

Thanks for the bitcoin. 

I was wondering about timeouts too.  My Internet connection is pretty flaky here.  What happens if it goes down for an hour part way through a hand?  Can I expect the hand to continue when I get back online?  What if I click 'hit', but the connection is down at the time?  Will the client deal nicely with not getting a server response and let me try again later?

I guess ideally I'd like to be able to have my browser crash part-way through a hand, then log in on a different computer and see the half-finished hand still in play.  But maybe that's expecting too much.

Heh, wow, awesome!  Thanks!

There's one other feature that might be useful -- user configurable timeout, so that like 15 minutes of inactivity I need to log back in to play.  (optional, of course)

Thanks for the praise! I'm glad it works well on your iPad - that's one of the huge benefits of HTML5 - automatic cross-device compatibility

We make use of jQuery and some parts of jQueryUI for the animations - but for the most part, we're just using pure HTML5 and CSS3. Specifically - we make heavy use of HTML5 -data attributes for communication between the client and the server. We also use CSS3 transitions.  We're planning on rolling out some 3D CSS transitions when we can work out some of the cross-browser kinks.


Yup! That's one of our core philosophies - stellar customer support across the board. This is why we spent so much time creating the provably fair shuffling system - we wanted our customers to know they were getting a fair game.


We are aware of the potential for swings, and we are fully capitalized to handle whatever swings come our way. We've done extensive statistical analysis, including random distribution analysis, and monte carlo simulations,  in order to ensure that our risk of ruin is infinitesimal.

It should just be 6 confirmations - which I admit still is actually quite a lot for smaller transactions. We are thinking of lowering this for smaller withdrawals, but we just want to be careful to not expose ourselves to any double spend attacks, which we've known has been the downfall to other bitcoin sites in the past. Since we allow you to play with 0 confirmations, we don't see this as a huge issue though.


That is a great point. We actually have the ability to cancel withdrawals on the backend, we just need to build a UI for it.


Ah yeah - that is indeed a poor user flow. We are probably going to change the whole concept how base currency works, such that you can play at a table in a different base currency than your account's base currency. Because you really shouldn't have to change your account settings just to temporarily play at a lower limit. Keep your eyes peeled for this change!


Yeah, good point. We figured that since you're withdrawing back into the real bitcoin network at this point, that it would make more sense to show BTC on this screen. But, given your feedback, I think it would be good to show the balance in both your base currency, and in BTC.

Thank you all so much for the feedback! This really is incredibly valuable to us as we continue to grow bitZino and make it a better site for all comers. Dooglus, and Stephen Gornick  - I've added a BTC to your accounts to thank you. Thanks again!

I just noticed that whatever the currency unit I set, the withdraw screen is in whole bitcoins.  It might make more sense to use the preferred base unit there too (and anywhere else that you show currency values - like in the history of deposits).

Wow.  You really are open to feedback aren't you!

I don't know if you're aware of how big the swings can be in blackjack.  Offering a 10 BTC max bet exposes you to the possibility of some pretty big losses if someone plays the max bet and has a good run.  Maybe you've considered that and are prepared to lose a lot, but I thought I should mention it.  There's probably a reason the other sites offer less than half that as their max bet.


Oh, I see.  The shuffle is applying a permutation to the pre-existing shuffle.  The client gets to decide the permutation, but doesn't have any way of knowing the original state, and so can't control the final state.

I made a small deposit last night, played a few hands, and withdrew - mostly just to check out how it worked.

It all went pretty smoothly, but I had the following comments:

* it seems you wait for 7 confirmations before marking my deposit as 'confirmed'?  that seems like a lot, but since you allow me to play unconfirmed balances it's not a problem

* if I had been able to 'cancel' my withdrawal request, I would have, and would have played more hands.  Is there any reason you wouldn't allow players to cancel a pending withdrawal request?

Finally, I just noticed a small issue:  if I click my name in the top right, select a new 'base currency', click 'update', then click 'back', then the "Welcome to Blackjack!" box in the centre of the page still shows my balance in the old currency units.  So if I was in mBTC before, but have less than 1 mBTC left, so I switch to uBTC, I still can't buy in because the buy-in box is still prompting for the number of mBTC to buy-in with.

If I click 'leave' in the top right then the currency units update, but that's a workaround I shouldn't have to use.

Took a look at this last, on my iPad. I lOve it!  And I am not really a BJ person, great job! 

Can I ask what libraries you are using, or did you write an entire HTML5/canvas graphics engine yourself?

Thanks for the heads-up! I was just using what I thought were standard rules, and hadn't really considered exactly what every else's house edge was. I think I will change the rules to allow for both hitting and re-splitting of split aces, which is more fun, and it'll bring the housed edge down to a meager 0.398%.


Heh, of course it does I meant to say that it could affect the output as the algorithm runs - ie, it could rely on the state of the deck in order to determine which operations to take in future steps (which I think algorithms like AES do). If this were the case, an attacker could presumably choose a seed that always brings certain cards to the top of the deck, regardless of the initial_shuffle.


I am paranoid I know, but ultimately, I don't think it adds that much complication, and it does let me feel better about letting clients choose a seed which determines the ultimate outcome of the deck

Are you aware that bitjack21 has only a 0.45% edge (they stand on soft 17), and strike sapphire's is only 0.50% (only 6 decks, let you hit split aces, but only split to 2 hands)?

I don't know about the other bitcoin blackjack offerings, but both of these have more attractive offerings than bitzino.


Well, the input does affect the output...  but like I said, the 2nd shuffle is entirely for the user's protection, not the site's.


The thing is, there are about 10^672 (2^2229) shuffles of 8 decks, but only about 10^78 (2^256) different sha256 hashes.  So each secret hash corresponds to about 10^594 (2^1973) different shuffles.

A rainbow table won't help.  Each time I see the same secret (which happens about once every lifetime-of-the-universe), it will correspond to a different shuffle.

ie. you really don't need salt in this case, and so can simplify the verification process.

Ah, I see it in Chromium 18 myself as well. Interestingly, it's not in Chrome 19. Also interestingly - the layout glitch goes away if you refresh the page.  I do have an idea of what causes this bug - I think it's due to the way webkit handles re-layouts of the page - I'm going to have to dive a little deeper though to figure out a fix. Thanks for the report!

Yeah, it is somewhat overkill, I agree. I was paranoid that there may be some vulnerability in Mersenne Twister that would cause the algorithm to somehow allow the input to affect the output. Now that I've gotten to know MT a little bit better, I see this is practically not possible given the way the algorithm is written.

The additional benefit that the server_seed provides though, is that it's effectively a random salt for the secret. Without the salt, a dedicated adversary could presumably start making a massive rainbow table of all known deck configurations. Again though, this is rally just paranoia - there's way too many deck configurations for this to be conceivable (especially with 8 deck blackjack). But I preferred to be a little paranoid than to have bitZino be exposed to a vulnerability.

I was thinking this would be the perfect use-case for a greasemonkey script. Because honestly, even if we allow you to log the hands client-side, you still have to trust that the javascript we're serving you isn't corrupted.

If anyone wants to build such a script, I'd be happy to help support it!


Dooglus already gave some good answers here (Wizard of Odds is one of my favorite sites!). But just to confirm: both the dealer and the player getting a blackjack is indeed a push. And all the rules dooglus listed are correct (indeed, you can't resplit aces), so it's a 0.66% house edge if you play optimally.

The words "your" and "deposit" overlap, as seen in this screenshot:



It's probably got to be a browser bug, since the HTML looks fine.

I'm using Chromium 18.0.1025.151 (Developer Build 130497 Linux) Ubuntu 12.04.

Isn't that always a push?


According to http://wizardofodds.com/games/blackjack/calculator/ it's around 0.66%.

8 decks
hit soft 17
double after split
double any 2 cards
resplit to 4 hands
can't resplit aces (right?)
can't hit split aces
only lose original bet to dealer BJ
no surrender
blackjack pays 3:2