Photochain Token

Collection of Ethereum smart contracts for the Photochain platform token

Technology

The project uses Truffle framework and the smart contracts are written in Solidity language (version 0.4.24).

To compile the smart contracts and run tests you need:

• NodeJS in version 6 or above
• NPM in version 5 or above

Token mechanics

Photochain token (ticker PHT) implements ERC20 interface and is compatible with all wallets and exchanges that support this standard.

The token extends the ERC20 interface in a backward compatible way with features essential for crowdsale distribution, like:

• minting tokens for specified addresses by an authorized party,
• finishing minting and preventing future inflation of supply,
• hard cap, limiting total supply to the maximum of 120 mln PHT tokens created in the process of minting

Only sold and allocated tokens are minted, there is no need to burn unsold tokens.

Minting

Minting features are implemented in MintableToken.sol and are based on Zeppelin contracts with minor changes covering clean code and compatibility with the newest Solidity compiler.

The token can be in two states:

custom_mark10 digraph G { mintable -> nonMintable [label="finishMinting"]; } custom_mark10

The contract starts in minting state. After calling finishMinting(), it is not possible to create any more tokens. Total supply becomes sealed and mint() function will revert when called.

Minting is possible only by the owner of the contract. By default, it is the deploying address, but can be changed later.

The hard cap serves as additional protection against exceeding the supply of 120 mln PHT. Total supply can be lower because only sold and allocated tokens are minted.

Distribution process

After crowdsale end, contributions will be processed taking into account time of contribution, crowdsale stage and vesting periods. Calculated amount of tokens will be minted for each contributor calling mint() function:

for (const contributor of contributors) {
    await pht.mint(contributor.address, contributor.amount);
}

await pht.finishMinting();

When all sold and allocated tokens are minted, finishMinting() will be called to prevent further creation of Photochain tokens. Participants will be able to see their balances and transfer tokens immediately. Those under agreed vesting period will have their tokens allocated in a dedicated smart contract that will release their tokens after expiration of vesting period.

Tests

To run tests, first install dependencies:

npm install

Then, run test script

npm test