Technology

Blockchain

Name: Polygon Network

Native token: $MATIC

Explorer: https://polygonscan.com/

GreenTrade Contract: https://polygonscan.com/token/0x37fecd093ea52c09a9a8c5541ac3c03bd46c2f8b

Polygon Network Definition

The Polygon network is Ethereum-native, aligned to be interoperable with all of Ethereum’s existing and even future infrastructures while offering a framework for its interoperability with other layer-2 solutions, sidechains and sovereign blockchains.

It is designed to improve the Ethereum network’s transaction processing speed and reduce transaction costs, also known as gas fees.

A layer-2 solution refers to a framework built on the base chain, to take some strain off it and complement its fundamental pain points.

It is a platform where developers can launch their own sovereign blockchains and decentralized applications, empowered by a set of advanced modules that enable the deployment of interconnected blockchain networks, with easily customizable functionality.

The network also refers to itself as “Ethereum’s internet of blockchains” because one of Polygon’s main missions is aggregating scalable solutions to support a multichain Ethereum ecosystem.

Native Token

$MATIC is an ERC-20 token, meaning that it's compatible with other Ethereum-based digital currencies. MATIC is used to govern and secure the Polygon network and to pay network transaction fees.

$MATIC is used to power the network and serve as a utility token for Polygon. It functions as the network’s main transactional currency and as a financial incentive for those who want to contribute to the ecosystem. It is also used as collateral in a process called staking, which enables users to participate in Polygon’s consensus mechanism to validate transactions in return for MATIC tokens.

Non-fungible Token

A non-fungible token (NFT) is a non-interchangeable unit of data stored on a blockchain, a form of digital ledger, that can be sold and traded. Types of NFT data units may be associated with digital files such as photos, videos, and audio. Because each token is uniquely identifiable, NFTs differ from blockchain cryptocurrencies, such as Bitcoin.

NFT ledgers claim to provide a public certificate of authenticity or proof of ownership, but the legal rights conveyed by an NFT can be uncertain. NFTs do not restrict the sharing or copying of the underlying digital files, do not necessarily convey the copyright of the digital files, and do not prevent the creation of NFTs with identical associated files.

In case of GreenTrade, the NFT represents a 1:1 digital replicate of a verified CO2e Carbon Credit.

MetaData

GreenTrade CO2e credits are coming with additional metadata, that is holding information like the origin, volume and certification data of a specific project.

The metadata of an NFT, whether developed according to the ERC721 or ERC1155 standard, is generally saved in the IPFS, a peer-to-peer protocol for saving multimedia files. This metadata is pinned to the protocol and returned as a hash to the Smart Contract. The resulting url, in the form https://ipfs.io/ipfs/QmZ8epAYRBVgmC89AkhMcYTvSXqaXoVyY1wDejcts8YfrF?filename=metadata1.json, is saved in the Smart Contract storage and associated with the ID of the corresponding token.

Once the specific information are submitted to the blockchain, these information are immutable.

ERC-721 Standard

The ERC-721 (Ethereum Request for Comments 721), proposed by William Entriken, Dieter Shirley, Jacob Evans, Nastassia Sachs in January 2018, is a Non-Fungible Token Standard that implements an API for tokens within Smart Contracts.

The ERC-721 introduces a standard for NFT, in other words, this type of Token is unique and can have different value than another Token from the same Smart Contract, maybe due to its age, rarity or even something else like its visual.

All NFTs have a uint256 variable called tokenId, so for any ERC-721 Contract, the pair contract address, uint256 tokenId must be globally unique.

ERC-1155 Standard

The ERC-1155 (Ethereum Request for Comments 1155) Standard is a interface for contracts that manage multiple token types. A single deployed contract may include any combination of fungible tokens, non-fungible tokens or other configurations (e.g. semi-fungible tokens).

This standard outlines a smart contract interface that can represent any number of fungible and non-fungible token types. Existing standards such as ERC-20 require deployment of separate contracts per token type. The ERC-721 standard’s token ID is a single non-fungible index and the group of these non-fungibles is deployed as a single contract with settings for the entire collection. In contrast, the ERC-1155 Multi Token Standard allows for each token ID to represent a new configurable token type, which may have its own metadata, supply and other attributes.

The _id argument contained in each function’s argument set indicates a specific token or token type in a transaction.

FIAT Payment Gateway

To time, the GreenTrade marketplace offers to pay in $USDC which is a cryptocurrency that is used across multiple blockchain networks. In order to accept non-crypto clients, we'll integrate a FIAT payment gateway that enables our customers to pay by credit card.