sec-rps

A rock-papers-scissors implementation on Solidity for the Security course at Universidad Austral

Project context

This link explains essentially the project structure.

Project requirements

• We should be able to create multiple matches simultaneously
• For each match we only have two players
• Each match consists of only on play
• For each match the amount needed to play must be declared (should be paid in WEI)
• To join a match you must pay the same as player 1
• The winning player takes everything. If it's a draw they both take back what they bet
• A match must be cancelable by player 1 (the creating player)
• After a user made its play then the other player has a timeout to make the play

We MUST use OpenZeppelin to get both Ownable and SafeMath

Useful links

• Solidity basic structures and types
• Solidity Events
• Solidity Maps
• Storage and memory explained
• Ownable and OpenZeppelin
• Only Owner
• Time
• View Functions
• Using fors
• Send vs Transfer

Notes

• We don't have to store old matches. As soon as a match finishes we can discard it

Happy Path

Match Creation

• In order to create a game there must not be any other current games with the same bet
  • E.g.,: if I bet 1 wei and there are no current games then I create a new game. If another player subscribes a bet but for 2 wei then another match gets created.
• At this stage there is a new game that contains only a bet and the player1
  • Player 1 can delete this match as soon as no one subscribes to his game. This would delete the game
  • Matches must die after ten minutes (?) of its original creation

Match Start

• Another player could be added as player 2 of that game, if that player subscribes the same amount of wei.
  • Once this happens the game status gets updated, and it cannot longer get deleted by any players.
  • An event must be created to notify the first player about the change of state in its game
  • We should be able to query the state of our games (maybe)
  • A timer starts forcing both players to play within that time.

Making a play

• Plays are simple: you can either play PAPER, ROCK or SCISSORS.
  • After a play we emit an event and another timeout is created, now to two minutes. The other player must play within that time
  • Plays cannot be changed
  • After each play we must check if the game is over or not
  • If the game is over it's a matter of computing the winner

Paying the players

• We must transfer the winning player the bet amount

Demo

• Create a Factory contract with player 1

Ownable Factory

• Deactivate the factory with the updateOpenForGames function set to false
• Try to create a game trying to register. It will not allow it
• Change to player2 and try to register. It will not allow it.
• As player2 try to updateOpenForGames to true. It will not allow it.
• Back to player1, open the factory (updateOpenForGames to true)

Match Register

• As player1 register a game with just one wei. It will allow it
• As player2 try to cancel the game created by player one. The game key is the value passed to create it. It will not allow it
• As player1 try to cancel the game created by yourself. It will allow it
• As player1 register a game with just one wei. It will allow it
• As player 2 register a game one wei. It will create a new game. Look for the game address in the logs and connect to it. Remember to select the factory contract and use the toAddress feature, not the Deploy button.

Match

• As player 3 try to make a move in the new Match. It will not allow it.
• As player 1 create a new move. Moves consist of a string that has first the Move ("r", "p", "s") and then your password. You must encode this move using keccack256 and pass it adding a "0x" at the beginning. Use "rMySecretPassword" as move.
• As player 1 try to repeat the move. It will not allow it.
• As player 1 try revealMove your move. Reveals consist of the decoded move string and the keccak of it. It will not allow it.
• As player 2 move, following the same steps than the player 1, but move "pMyOtherSecretPassword".
• As player 1 try to revealMove your move. It will allow it.
• As player 2 try to revealMove your move. It will allow it. This will output the result. It should be a player 2 win.