dice: A C++ repository from qq776355102

DICE

This contract implements a simple DICE game between two players with 50/50 odds of winning.

Before playing all players deposit funds into their @dice account just like the @exchange contract

Player 1 proposes to bet 1 EOS and submits SHA256(secret1)
Player 2 proposes to bet 1 EOS and submits SHA256(secret2)

Because Player 1 and 2 bet equal amounts their orders are matched and the game begins.

A Player reveales their secret
A 5 minute deadline starts whereby the first to reveal automatically wins unless the other player reveals
The other player reveals and a winner is chosen and paid based upon the value of sha256( cat(secret1,secret2) )
After the deadline anyone can trigger a default claim and the rewards

Economic Incentive for Interface Developers

A variation on this game would be to add an additional information on offer creation that will get paid a commission when the player wins. With this commission in place there is financial incentive for a service provider to continue to execute the game in a timely manner as well as provide quality and entertaining interfaces on top of this game.

Other Games

This same basic model can be used to build more robust games.

Potential Vulnerabilities

Block Producers may exclude reveal transaction
Losers may force winner to wait 5 minutes to get rewards
Service providers may fail to auto-reveal on your behalf
You may lose internet connectivity mid-game
A blockhain reorganization could cause some havock if secrets are revealed too quickly
- @dice could protect users by rejecting reveals until a game creation is irreversible (about 45 seconds max)
- users could take risk themselves by deciding how many confirmations are required
- for small amounts it probably doesn't matter
- under normal operation of DPOS chains there are few if any chain reorganizations

Example game session using cleos

Prerequisites

Wallet must be unlock and have at least the following private keys

5KQwrPbwdL6PhXujxW37FSSQZ1JiwsST4cqQzDeyXtP79zkvFD3 5Jmsawgsp1tQ3GD6JyGCwy1dcvqKZgX6ugMVMdjirx85iv5VyPR

Upload bios contract

cleos set contract eosio build/contracts/eosio.bios -p eosio

Ceate eosio.token account

cleos create account eosio eosio.token EOS7ijWCBmoXBi3CgtK7DJxentZZeTkeUnaSDvyro9dq7Sd1C3dC4 EOS7ijWCBmoXBi3CgtK7DJxentZZeTkeUnaSDvyro9dq7Sd1C3dC4

Set eosio.token contract to eosio.token account

cleos set contract eosio.token build/contracts/eosio.token -p eosio.token

Create dice account

cleos create account eosio dice EOS7ijWCBmoXBi3CgtK7DJxentZZeTkeUnaSDvyro9dq7Sd1C3dC4 EOS7ijWCBmoXBi3CgtK7DJxentZZeTkeUnaSDvyro9dq7Sd1C3dC4

Set dice contract to dice account

cleos set contract dice build/contracts/dice -p dice

Create native EOS token

cleos push action eosio.token create '[ "eosio", "1000000000.0000 EOS", 0, 0, 0]' -p eosio.token

Create alice account

cleos create account eosio alice EOS7ijWCBmoXBi3CgtK7DJxentZZeTkeUnaSDvyro9dq7Sd1C3dC4 EOS7ijWCBmoXBi3CgtK7DJxentZZeTkeUnaSDvyro9dq7Sd1C3dC4

Create bob account

cleos create account eosio bob EOS7ijWCBmoXBi3CgtK7DJxentZZeTkeUnaSDvyro9dq7Sd1C3dC4 EOS7ijWCBmoXBi3CgtK7DJxentZZeTkeUnaSDvyro9dq7Sd1C3dC4

Issue 1000 EOS to alice

cleos push action eosio.token issue '[ "alice", "1000.0000 EOS", "" ]' -p eosio

Issue 1000 EOS to bob

cleos push action eosio.token issue '[ "bob", "1000.0000 EOS", "" ]' -p eosio

Allow dice contract to make transfers on alice behalf (deposit)

cleos set account permission alice active '{"threshold": 1,"keys": [{"key": "EOS7ijWCBmoXBi3CgtK7DJxentZZeTkeUnaSDvyro9dq7Sd1C3dC4","weight": 1}],"accounts": [{"permission":{"actor":"dice","permission":"active"},"weight":1}]}' owner -p alice

Allow dice contract to make transfers on bob behalf (deposit)

cleos set account permission bob active '{"threshold": 1,"keys": [{"key": "EOS7ijWCBmoXBi3CgtK7DJxentZZeTkeUnaSDvyro9dq7Sd1C3dC4","weight": 1}],"accounts": [{"permission":{"actor":"dice","permission":"active"},"weight":1}]}' owner -p bob

Alice deposits 100 EOS into the dice contract

cleos push action dice deposit '[ "alice", "100.0000 EOS" ]' -p alice

Bob deposits 100 EOS into the dice contract

cleos push action dice deposit '[ "bob", "100.0000 EOS" ]' -p bob

Alice generates a secret

openssl rand 32 -hex
28349b1d4bcdc9905e4ef9719019e55743c84efa0c5e9a0b077f0b54fcd84905

Alice generates sha256(secret)

echo -n '28349b1d4bcdc9905e4ef9719019e55743c84efa0c5e9a0b077f0b54fcd84905' | xxd -r -p | sha256sum -b | awk '{print $1}'
d533f24d6f28ddcef3f066474f7b8355383e485681ba8e793e037f5cf36e4883

Alice bets 3 EOS

cleos push action dice offerbet '[ "3.0000 EOS", "alice", "d533f24d6f28ddcef3f066474f7b8355383e485681ba8e793e037f5cf36e4883" ]' -p alice

Bob generates a secret

openssl rand 32 -hex
15fe76d25e124b08feb835f12e00a879bd15666a33786e64b655891fba7d6c12

Bob generates sha256(secret)

echo -n '15fe76d25e124b08feb835f12e00a879bd15666a33786e64b655891fba7d6c12' | xxd -r -p | sha256sum -b | awk '{print $1}'
50ed53fcdaf27f88d51ea4e835b1055efe779bb87e6cfdff47d28c88ffb27129

Bob also bets 3 EOS (a game is started)

cleos push action dice offerbet '[ "3.0000 EOS", "bob", "50ed53fcdaf27f88d51ea4e835b1055efe779bb87e6cfdff47d28c88ffb27129" ]' -p bob

Dice contract tables right after the game started

cleos get table dice dice account

{
  "rows": [{
      "owner": "alice",
      "eos_balance": "97.0000 EOS",
      "open_offers": 0,
      "open_games": 1
    },{
      "owner": "bob",
      "eos_balance": "97.0000 EOS",
      "open_offers": 0,
      "open_games": 1
    }
  ],
  "more": false
}

cleos get table dice dice game

{
  "rows": [{
      "id": 1,
      "bet": "3.0000 EOS",
      "deadline": "1970-01-01T00:00:00",
      "player1": {
        "commitment": "d533f24d6f28ddcef3f066474f7b8355383e485681ba8e793e037f5cf36e4883",
        "reveal": "0000000000000000000000000000000000000000000000000000000000000000"
      },
      "player2": {
        "commitment": "50ed53fcdaf27f88d51ea4e835b1055efe779bb87e6cfdff47d28c88ffb27129",
        "reveal": "0000000000000000000000000000000000000000000000000000000000000000"
      }
    }
  ],
  "more": false
}

Bob reveals his secret

cleos push action dice reveal '[ "50ed53fcdaf27f88d51ea4e835b1055efe779bb87e6cfdff47d28c88ffb27129", "15fe76d25e124b08feb835f12e00a879bd15666a33786e64b655891fba7d6c12" ]' -p bob

Game table after bob revealed (now the game has a deadline for alice to reveal)

cleos get table dice dice game

{
  "rows": [{
      "id": 1,
      "bet": "3.0000 EOS",
      "deadline": "2018-04-17T07:45:49",
      "player1": {
        "commitment": "d533f24d6f28ddcef3f066474f7b8355383e485681ba8e793e037f5cf36e4883",
        "reveal": "0000000000000000000000000000000000000000000000000000000000000000"
      },
      "player2": {
        "commitment": "50ed53fcdaf27f88d51ea4e835b1055efe779bb87e6cfdff47d28c88ffb27129",
        "reveal": "15fe76d25e124b08feb835f12e00a879bd15666a33786e64b655891fba7d6c12"
      }
    }
  ],
  "more": false
}

Alice reveals her secret (the winner is determined, the game is removed)

cleos push action dice reveal '[ "d533f24d6f28ddcef3f066474f7b8355383e485681ba8e793e037f5cf36e4883", "28349b1d4bcdc9905e4ef9719019e55743c84efa0c5e9a0b077f0b54fcd84905" ]' -p alice

Balance of the accounts after game ends

cleos get table dice dice account

{
  "rows": [{
      "owner": "alice",
      "eos_balance": "103.0000 EOS",
      "open_offers": 0,
      "open_games": 0
    },{
      "owner": "bob",
      "eos_balance": "97.0000 EOS",
      "open_offers": 0,
      "open_games": 0
    }
  ],
  "more": false
}

Alice withdraw from her dice account 103 EOS

cleos push action dice withdraw '[ "alice", "103.0000 EOS" ]' -p alice

Balance of alice after withdraw

cleos get currency balance eosio.token alice eos
1003.0000 EOS

qq776355102/dice