Envoy

An ERC20-compliant token equipped with delegated transferring.

Envoy is an ERC20 token that borrows from the ERC865 standard. This allows tokens that descend from Envoy to be transferred without the sender having any Ether to spend as gas, as long as a delegate with Ether is willing to broadcast the transaction (while taking a fee as payment).

How do I incorporate it in my project?

Install via NPM to your Truffle project.

> npm install -S envoy-token

and import the installed package.

pragma solidity a.solc.version;

import "envoy-token/contracts/EnvoyToken.sol";

contract MyToken is EnvoyToken {}

Or import via the Github url!

pragma solidity a.solc.version;

import "github.com/aunyks/envoy-token/contracts/EnvoyToken.sol";

contract MyToken is EnvoyToken {}

API

This token contains all functions from the ERC20 standard that track supply, balances, and allowances. Thus, it does not have the symbol(), name(), and decimals() members.

The Envoy token adds two functions from the ERC865 standard: transferPreSigned() and transferPreSignedHashing().

transferPreSigned(
bytes signature,
address recipient,
uint256 value,
uint256 fee,
uint256 nonce
)
Returns true if transaction succeeds.

• signature -- A byte array of the signature of keccak256(tokenContractAddress, recipient, value, fee, nonce)
• recipient -- The account to which the tokens will be sent.
• value -- The number of tokens to be sent to the recipient.
• fee -- The number of tokens to be sent to the delegate.
• nonce -- A transaction nonce.

transferPreSignedHashing(
address token,
address recipient,
uint256 value,
uint256 fee,
uint256 nonce
)
Returns the bytes32 digest of the function parameters after tightly packing.

• token -- The address of the token contract.
• recipient -- The account to which the tokens will be sent.
• value -- The number of tokens to be sent to the recipient.
• fee -- The number of tokens to be sent to the delegate.
• nonce -- A transaction nonce.

Acknowledgements

Some code in this repository is borrowed from the OpenZeppelin Solidity project.

LICENSE

This project is licensed under the MIT License. If your project uses Envoy, this project must be publicly attributed.
Copyright (c) 2018 Gerald Nash