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0.0.3 • Public • Published

Integration of TCRs, CPM and Ocean Tokens with Solidity

name: Integration of TCRs, CPM, and Ocean tokens with Solidity
type: development
status: initial draft
editor: Fang Gong <>
collaborator: Aitor Argomaniz <>
date: 06/01/2018

1. Objective

In this POC, we put following modules together:

  • TCRs: users create challenges and resolve them through voting to maintain registries;
  • Ocean Tokens: the intrinsic tokens circulated inside Ocean network, which is used in the voting of TCRs;
  • Curated Proofs Market: the core marketplace where people can transact with each other and curate assets through staking with Ocean tokens.

2. Public Interface

The following project exposes the following public interfaces:

2.1 Curation Market

//Allows a user to start an application. Takes tokens from user and sets apply stage end time.
function apply(bytes32 _listingHash, uint _amount, string _data);

// Allows the owner of a listingHash to increase their unstaked deposit.
function deposit(bytes32 _listingHash, uint _amount);

//Allows the owner of a listingHash to decrease their unstaked deposit.
function withdraw(bytes32 _listingHash, uint _amount);

// Allows the owner of a listingHash to remove the listingHash from the whitelist
function exit(bytes32 _listingHash);

// Starts a poll for a listingHash which is either in the apply stage or already in the whitelist. 
function challenge(bytes32 _listingHash, string _data);

// Updates a listingHash’s status from ‘application’ to ‘listing’ or resolves a challenge if one exists.
function updateStatus(bytes32 _listingHash);

// Called by a voter to claim their reward for each completed vote.
function claimReward(uint _challengeID, uint _salt);

// Calculates the provided voter’s token reward for the given poll.
function voterReward(address _voter, uint _challengeID, uint _salt);

// Determines whether the given listingHash be whitelisted.
function canBeWhitelisted(bytes32 _listingHash);

// Returns true if the provided listingHash is whitelisted
function isWhitelisted(bytes32 _listingHash);

// Determines the number of tokens awarded to the winning party in a challenge.
   function determineReward(uint _challengeID);

2.2 Marketplace

// Register provider and assets (upload by changing uploadBits)
function register(uint256 assetId) public returns (bool success);

// publish consumption information about an Asset
function publish(uint256 assetId, bytes32 url, bytes32 token) external returns (bool success);

// purchase an asset and get the consumption information
function purchase(uint256 assetId) external returns (bytes32 url, bytes32 token);

// Return the list of available assets
function listAssets() external view returns (uint256[50]); 

2.3 Query functions

// Return the number of drops associated to the message.sender to an Asset 
function dropsBalance(uint256 assetId) public view returns (uint256);

// Return true or false if an Asset is active given the assetId
function checkAsset(uint256 assetId) public view returns (bool);

// Get the url attribute associated to a given the assetId
function getAssetUrl(uint256 assetId) public view returns (bytes32);

// Get the token attribute associated to a given the assetId
function getAssetToken(uint256 assetId) public view returns (bytes32);

// Retrieve the msg.sender Provider token balance
function tokenBalance() public view returns (uint256);

2.3 Events

// Asset Events
event AssetRegistered(uint256 indexed _assetId, address indexed _owner);
event AssetPublished(uint256 indexed _assetId, address indexed _owner);
event AssetPurchased(uint256 indexed _assetId, address indexed _owner);

// Token Events
event TokenWithdraw(address indexed _requester, uint256 amount);
event TokenBuyDrops(address indexed _requester, uint256 indexed _assetId, uint256 _ocn, uint256 _drops);
event TokenSellDrops(address indexed _requester, uint256 indexed _assetId, uint256 _ocn, uint256 _drops);

3. File Structure

There are several folders and each includes solidity source files for each module:

  • bondingCurve: it caculates the bonding curve values when users purchase drops or sell drops in the marketplace;
  • plcrvoting: Partial Lock Commit Reveal Voting System;
  • tcr: the TCRs related files;
  • token: Ocean tokens based on ERC20 standard;
  • zeppelin: the library files from OpenZeppelin;
  • market.sol: curated proofs market (on-going work)

4. Architecture of Modules

The dependency between different modules are illustrated as below:

  • Marketplace (Market.sol) sends listing hash to TCRs (Registry.sol) so that to create challenges.
  • Users can use Ocean Tokens (OceanToken.sol) to vote for or against (PLCRVoting.sol).
  • Voting is configured with the parameters (Parameterizer.sol).
  • Marketplace uses bonding curve (BancorFormula.sol) to determine the price of drops.
  • BancorFormula calculates the power function (Power.sol).
  • TCRs (Registry.sol) send the voting result back to Marketplace (Market.sol).

5. Architecture of solidity Market contract

First draft of UML class diagram

6. Compile, Migrate and Test

Use $ npm install to download all the required libraries

Use $ truffle compile to compile those solidity files:

Then deploy them into testRPC $ truffle migrate:


  • there are Error: run out of gas because we try to deploy so many contracts as one single transaction. Tune the gas value in truffle.js file to make them run through.
  • we enable the solc optimizer to reduce the gas cost of deployment. It can now be deployed with less gas limit such as "gas = 5000000"
  • no need to update the "from : 0x3424ft..." in truffle.js and it will use the first account in testRPC or ganache-cli by default.

Test them with $ truffle test test/registry.js:




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