[ANN] DoubleMyCoins.com! - 50/50 Chance Provably Fair [NEW DESIGN!]

[DoubleMyCoins]

Update 6/20/13:

Site has a new design, enjoy! http://doublemycoins.com

http://img10.imageshack.us/img10/7526/y9r2.jpg

---------------------

Introducing DoubleMyCoins!

Please help test with amounts .0006 to 1 BTC. Experience ZERO House Fee during testing!

How about a 50/50 game where you actually do something

Your task is to find the Red Ace! It's a 50/50 chance which is provably fair. We use true random numbers from random.org. If you choose correctly your coins are DOUBLED (less 1.9% house fee).

Start playing instantly. See How it Works for details, and let me know what you think!

[Yurkov]

- Your demo game is just a simple script that always makes the left card win, no matter what.
- You just have 2 posts
- You have no transactions whatsoever, so how will you pay us out?
- You use the same BTC address, any provably fair game generates a temporary wallet
- Site is very poorly written and sketchy

4/10

[ironcross360]

2/10...

[DoubleMyCoins]

- Your demo game is just a simple script that always makes the left card win, no matter what.
- You just have 2 posts
- You have no transactions whatsoever, so how will you pay us out?
- You use the same BTC address, any provably fair game generates a temporary wallet
- Site is very poorly written and sketchy

4/10

Thanks for taking a look!  

Answering your points...

- Yes, this is just to show how the very simple game works (and see how long it take for people to realize it's the same demo position)
- New forum account but not new to Bitcoin, hopefully this thread can build trust - test with .0006 if you like (that's about $0.08)
- I have BTC to cover payouts
- Your BTC deposit address changes every time your session changes, but not simply for playing new games
- It's a very simple game I had interest in making. If it does well I'll upgrade it.

[DoubleMyCoins]

2/10...

Hey, it looks simple, but actually took a while to set up! I would think the suspense of picking the right card would be worth something. As I said above I'll upgrade it if it does well enough.  

[firstlast]

He doubled his post count, so I trust he can double your coins as well.

[DoubleMyCoins]

He doubled his post count, so I trust he can double your coins as well.

lol

[DoubleMyCoins]

Okay, I'll send .1 BTC to the first 10 people to post their game hash and desired wallet address. Your game hash is available by clicking to view the page source code of your game.

[vlees]

No idea what my game hash is, but it wants me to pay to 13Bp6ytDR4J3v734y14ytSXFS76K7JfzD5.

The wallet you may send the 0.1 BTC to is 1QtHuSHkeMyZnKFHhf7UeEs4NusVnrVQq

EDIT:
Also from first post:

Experience ZERO House Fee during testing!

How about a 50/50 game where you actually do something

Your task is to find the Red Ace! It's a 50/50 chance which is provably fair. We use true random numbers from random.org. If you choose correctly your coins are DOUBLED (less 1.9% house fee).

-----

So what is it?

[DoubleMyCoins]

No idea what my game hash is, but it wants me to pay to 13Bp6ytDR4J3v734y14ytSXFS76K7JfzD5.

The wallet you may send the 0.1 BTC to is 1QtHuSHkeMyZnKFHhf7UeEs4NusVnrVQq

EDIT:
Also from first post:

Experience ZERO House Fee during testing!

How about a 50/50 game where you actually do something

Your task is to find the Red Ace! It's a 50/50 chance which is provably fair. We use true random numbers from random.org. If you choose correctly your coins are DOUBLED (less 1.9% house fee).

-----

So what is it?

To start playing a game send an amount (.0006 to 1 BTC during testing) to the address it tells you. Your game starts automatically.

If you click to view the page source code you will see your game hash just under the [body] tag. This is how you know the game is provably fair.

After you make your choice you can click to view the source code again and you will see the message with random number used and secret key under the [body] tag as well as the game hash. Using these values anyone can verify that the random number is the same as before you made your choice, because it's not possible to change it and get the same hash value. Changing even one thing would dramatically change the hash.

The 1.9% house fee is waived during testing.

[KingOfSports]

Here is the address it wants me to send to, you can credit .1 directly to my account thanks!
13ZY8SsE5HB8Zd8stSpexZiVz8NqJKSUqi

[dooglus]

Okay, I'll send .1 BTC to the first 10 people to post their game hash and desired wallet address. Your game hash is available by clicking to view the page source code of your game.

I clicked 'play'.  It gave me an address to send coins to, but no hash yet.

I sent 0.0006 BTC to the address it gave me.  The page automatically refreshed pretty quickly.  It now says "Your coins: 0.0006" and the source of the page has the following, just under the <body> tag:

<!--
PROVABLY FAIR GAME INFO

Final hash: 0f8a39ef65dfbfb74239a956447b94e84c10695765d2520d020c9e20acb7301002a07186372d61b 1a6d6e2062262bd981225aff5c5c1a60be1fe9952055785ed
//-->

So I'll pick a card.  Hmm.  Left or right?

Left.

"Sorry, you lost".

Now the source of that page has this after the <body> tag:

<!--
PROVABLY FAIR GAME INFO

message: "Random number is 527128."
message & hash: "Random number is 527128. Hash: ff72d43539e7dd82fc0bb861c77d87a286ab49e13149744e42e6980ba2b9495dd952461ecaadff3 01575b152a58f5db7d02a7b280adc3c5ec5ef0ac249efb449"

final hash: 0f8a39ef65dfbfb74239a956447b94e84c10695765d2520d020c9e20acb7301002a07186372d61b 1a6d6e2062262bd981225aff5c5c1a60be1fe9952055785ed

secret key: 796330129344107608179585
//-->

I don't understand what's going on there.  I'm not able to reproduce the results.  What hash function are you using?  What strings are you hashing?  Perhaps give some command lines that we can follow to get from the random number to the hash.  And tell us how the random number determines where the red card is, too.

Please send the 0.1 BTC to 1PrVzMVozDGj1qfeDN3TtA7ps3i3qE8Awk

I'll post to this thread when it arrives.

Thanks.

[DoubleMyCoins]

Hi dooglus,

I was waiting for your verdict  

You actually found a minor bug. Not a bug really, just the need to add " Hash: " to the message given to the player for the provably fair info. It's now updated. So, to check you would take that message and apply HMAC SHA-512, then append that hash to the message, and hash the whole thing which gives the final game hash.

Here is the code in PHP:

Code:

<?php


  $secretkey = "796330129344107608179585"; //put the secret key here
  $randomnumber = "527128"; //put the random number here

  $message = "Random number is $randomnumber. Hash: ";

  $hashmessage = hash_hmac('sha512', $message, $secretkey);

  $messageandhash = $message.$hashmessage;

  $finalhash = hash_hmac('sha512', $messageandhash, $secretkey);

  echo ("<p>Message: $message <p> Message and hash: $messageandhash <p>Final hash: $finalhash");

?>

Here is the output for those values:

Code:

Message: Random number is 527128. Hash:

Message and hash: Random number is 527128. Hash: ff72d43539e7dd82fc0bb861c77d87a286ab49e13149744e42e6980ba2b9495dd952461ecaadff301575b152a58f5db7d02a7b280adc3c5ec5ef0ac249efb449

Final hash: 0f8a39ef65dfbfb74239a956447b94e84c10695765d2520d020c9e20acb7301002a07186372d61b1a6d6e2062262bd981225aff5c5c1a60be1fe9952055785ed

Your .1 BTC has been sent. Thanks!

[dooglus]

Please send the 0.1 BTC to 1PrVzMVozDGj1qfeDN3TtA7ps3i3qE8Awk

I'll post to this thread when it arrives.

OP delivars:

https://blockchain.info/tx/2c084ac54bd9453f562dab1a3bd33860614e86ccbb5d3d0e921b7490ebbe9fba

[dooglus]

Here is the code in PHP:

Here's what I meant about a command line.  See the bottom of this page?

https://coinroll.it/bet/fa870f1e518e

Command line verification (bash shell)

echo -n 'b8d60cff5ca2fcd20fbd27987c671a65b32d40ed127c7a4bcaeb251600fc1365:0' | openssl dgst -sha512 -hmac 'WW4hgGFOiVZ0ITgIt89xG2R5OuAiEBTx3FDk2y2oDfJc94JkurVqn2mDwyk9oyr7' | sed 's/^.* //' | cut -c1-4 | xargs -I{} printf "%d\n" 0x{}

Also, it's still not clear how you decide which card is the red one.  Is it just whether the random number is even or odd?

Edit: also, I think your scheme is overly complex.  All you need to do is:

1) pick 'left' or 'right' at random
2) pick a longish random string
3) concatenate 1) and 2)
4) sha512 hash 3)
5) publish 4) before the game, and 3) after.

No need for hmac, or a 'secret', or even a random number.  Just a result (1) and a string to make reversing the hash impossible (2).

Edit2: I wouldn't normally send coins to games with no history or reputation, but I figured it wouldn't be worth your while buying a domain for a 0.0006 BTC scam...

[fredtrader]

I deposited 0.001 to try out the game to 13sCVRnMXKh2ZqhsrBo2aJJPaPEzcqxJSR , won once for 0.002 then lost it, not sure where to find the game hash, I would like to take the 0.1 btc offer to address 1ERd9wQz7pJ2S4EedrMLQoSbivPpZh8gCD

[DoubleMyCoins]

Here is the code in PHP:

Here's what I meant about a command line.  See the bottom of this page?

https://coinroll.it/bet/fa870f1e518e

Command line verification (bash shell)

echo -n 'b8d60cff5ca2fcd20fbd27987c671a65b32d40ed127c7a4bcaeb251600fc1365:0' | openssl dgst -sha512 -hmac 'WW4hgGFOiVZ0ITgIt89xG2R5OuAiEBTx3FDk2y2oDfJc94JkurVqn2mDwyk9oyr7' | sed 's/^.* //' | cut -c1-4 | xargs -I{} printf "%d\n" 0x{}

Also, it's still not clear how you decide which card is the red one.  Is it just whether the random number is even or odd?

Edit: also, I think your scheme is overly complex.  All you need to do is:

1) pick 'left' or 'right' at random
2) pick a longish random string
3) concatenate 1) and 2)
4) sha512 hash 3)
5) publish 4) before the game, and 3) after.

No need for hmac, or a 'secret', or even a random number.  Just a result (1) and a string to make reversing the hash impossible (2).

Edit2: I wouldn't normally send coins to games with no history or reputation, but I figured it wouldn't be worth your while buying a domain for a 0.0006 BTC scam...

Yes, you can check the value various ways. The point is the value can be verified and can't be changed by the house.

If the last digit of the random number is odd the Red Ace is positioned left, and right if even. Sorry for not adding that in this thread, it's on the Provably Fair page.

I agree the system can be done differently. The game you see now is slightly different from how it started. The main thing I wanted to achieve was true randomness, so I could even play the game myself. There was a study done by some professor that asked if people had some ability to predict the future. He used a game similar to this and over trials found some people seemed to be able to predict the right choice with slightly better than 50%, and it was a mystery how that happened.

So I take truly random numbers from random.org to ensure randomness and run them through the system.

[DoubleMyCoins]

Here is the address it wants me to send to, you can credit .1 directly to my account thanks!
13ZY8SsE5HB8Zd8stSpexZiVz8NqJKSUqi

I couldn't find any deposit you made for 13ZY8SsE5HB8Zd8stSpexZiVz8NqJKSUqi

I deposited 0.001 to try out the game to 13sCVRnMXKh2ZqhsrBo2aJJPaPEzcqxJSR , won once for 0.002 then lost it, not sure where to find the game hash, I would like to take the 0.1 btc offer to address 1ERd9wQz7pJ2S4EedrMLQoSbivPpZh8gCD

Sent .1 BTC to 1ERd9wQz7pJ2S4EedrMLQoSbivPpZh8gCD

https://blockchain.info/tx/0522f7cebdf2d377fcab1df790cbaccf6138f05296108f7d638c6693608c15eb

Thanks!

[fredtrader]

I deposited 0.001 to try out the game to 13sCVRnMXKh2ZqhsrBo2aJJPaPEzcqxJSR , won once for 0.002 then lost it, not sure where to find the game hash, I would like to take the 0.1 btc offer to address 1ERd9wQz7pJ2S4EedrMLQoSbivPpZh8gCD

Sent .1 BTC to 1ERd9wQz7pJ2S4EedrMLQoSbivPpZh8gCD

Thanks!

Received thanks https://blockchain.info/tx/0522f7cebdf2d377fcab1df790cbaccf6138f05296108f7d638c6693608c15eb

I'll try another bet on your site shortly

[dooglus]

So I take truly random numbers from random.org to ensure randomness and run them through the system.

I think that's a great idea.

But you don't need to tell us what random number you got.  Just tell us 'left' or 'right', with junk on the end, and hashed.

Then we don't need to worry about a 'secret', how to run hmac, etc.  We just put the "left:wklfjslfkhrewg" string the you show after the game into a webpage that offers sha512 to people who don't know how to command line, check that the hash is the same as the one you showed before the game, and you're done.

Here is the address it wants me to send to, you can credit .1 directly to my account thanks!
13ZY8SsE5HB8Zd8stSpexZiVz8NqJKSUqi

I couldn't find any deposit you made for 13ZY8SsE5HB8Zd8stSpexZiVz8NqJKSUqi

I don't think he's saying he deposited, just that that's the address it gave.

For those who can't find the provably fair info, right-click on the page and select 'view page source' or similar.  It's near the top, just after '<body>'.  But you have to send coins and wait for the page to update before you get the hash.