StandardBounties

Version 0.0.1

1. Rationale
2. Implementation
3. Development
4. Documentation

A set of standard contracts to be used as interfaces for any kind of bounty, either qualitative or quantitative in nature.

1. Rationale

Ethereum smart contracts can trivially facilitate transactions of resources (or tokens) between individuals or groups, but service transactions are more complex. Requesting individuals (issuers) must first approve the work they're receiving before paying out funds, meaning bounty hunters must have trust that the issuer will pay them in the spirit of the original contract.

The StandardBounty.sol contract facilitates transactions on qualitative data (often representing artifacts of completion of some service), allowing bounty issuers to systematically approve the work they receive.

2. Implementation

A single bounty contract can be used to pay amounts of ETH or a given token, based on the successful completion of specific Milestones. The contract aims to reduce the necessary trust in the issuer by forcing them to deposit sufficient Ether (or tokens) to at minimum pay out each milestone once.

• A bounty begins in the Draft state, where the requirements, deadline, arbiter, and reward amounts can still be altered.

  In this state, the various functions which can be called are:

  • contribute() [ANYONE]: contributes ETH (or tokens) to the bounty
  • activateBounty() [ONLY ISSUER]: This will activate the bounty
  • killBounty() [ONLY ISSUER]: This will kill the bounty

  As well as several functions to alter the bounty details:

  • changeDeadline() [ONLY ISSUER]
  • changeData() [ONLY ISSUER]
  • changeContact() [ONLY ISSUER]
  • changeArbiter() [ONLY ISSUER]
  • changeFulfillmentAmounts() [ONLY ISSUER]

• A bounty transitions to the Active state when the issuer calls activateBounty().

  This is only possible if

  • the bounty hasn't expired (isn't past its deadline)
  • the bounty has sufficient funds to pay out each milestone at least once

  Once a bounty is Active, bounty hunters can submit fulfillments for the various milestones, and the bounty issuer can approve fulfillments to pay out the rewards.

  In this state, the various functions which can be called are:

  • fulfillBounty() [ANYONE BUT ISSUER]:
  • acceptFulfillment() [ONLY ISSUER]:
  • fulfillmentPayment() [FULFILLER]:
  • killBounty() [ONLY ISSUER]:

• A bounty transitions to the Dead state when the issuer calls killBounty(), which drains the contract of its balance, less the necessary funds to pay out fulfillments which have already been accepted but aren't yet paid out.

  In this state, the only functions which can be called are:

  • extendDeadline() [ONLY ISSUER]
  • contribute() [ANYONE]
  • activateBounty() [ONLY ISSUER]

2.1 Invariant check pattern for CodeBugBounty.sol

Code bug bounties are a specific implementation of the StandardBounty, where the 0th milestone is reserved for fulfillments which break a contracts invariants. Its use requires the implementation of Bountied.sol, with special care given to the checkInvariants() function that checks the correctness of the contract's state.

3. Development

All the extension bounty types (particular cases like CodeBugBounty.sol) musn't break the state transitions as described above.

4. Documentation

For thorough documentation of all functions, see the documentation