Blockchain Introduction

Resources>

Resources #

Notes>

Notes #

what is blockchain>

what is blockchain #

The blockchain solution in IoT / Supply chain are changing “Mesh” network to a “Star Network
each parties access and write to the “blockchain network”. not more api integration between parties

How to use it>

How to use it #

How it work>

How it work #

use cryptography methods to ensure the integrity of a public writable database
proof of work, proof of stake, proff

How to implement>

How to implement #

solidity
node.js
truffle
web3.js

Any product (e.g crypto currency/ nft)>

Any product (e.g crypto currency/ nft) #

Networks>

Networks #

Use Cases

Public>

Public #

Private (have acl)>

Private (have acl) #

each parties setup servers to join the blockchain network
all parties hold the data but they can set access right to the data
Hyperledger Fabric

Decentralized Storage>

Decentralized Storage #

IPFS

Staking>

Staking #

CrowdSale>

CrowdSale #

user -> sale contract -> nft contract

Lottery>

Lottery #

ashisherc/advanced-solidity-lottery-application

NFT>

NFT #

Swap / Farming>

Swap / Farming #

ask people input proportion of coin into the pool, like eth:bnb. so people can trade between eth and bnb
use Oracles for pricing…a smart contract which referencing different sources from other swap exchange & their coin pair pool size
pancakeswap(bsc)
uniswap(eth)

What is ECR20 721 1155>

What is ECR20 721 1155 #

ECR20 = coin
ECR721 = NFT
ECR1155 = 1 contract with multi token, eg: game item

What is smart contract>

What is smart contract #

Code stored on blockchain

Demo>

Demo #

NFT Contract>

NFT Contract #

Common Functions

Mintable (increase supply)
Burnable (reduce supply)
Pausable (freeze the contract, for upgrade)
Access control: Roles (multi ac, multi actions) / Ownable (single ac, all actions)
Upgradeability (Transpart / UUPS) - proxy pattern
Timelock
Votes

NFT metadata>

NFT metadata #

{
  "boosterId": 10000000195586,
  "id": "10000586756",
  "txHash": "0xff318896b78fd77aadf19f94b7434d1a0ea5ffddfc88b6966d92d75c69f80dd1",
  "randomNumber": "0xc55ec3b26d0bdec23fd2f9e29ae34d54e0d457ef1d413b5c537b0383330575f0",
  "image": "https://assets.polkamon.com/images/Unimons_T08C02H06B04G00.jpg",
  "external_url": "https://polkamon.com/polkamon/T08C02H06B04G00",
  "description": "Mindful of a million things, the Unisheep are Polkamon creatures that can graze and gander the day away. Creating an environment to actively direct these creatures helps them focus on one particular topic.",
  "name": "Unisheep",
  "initialProbabilities": {
    "horn": 0.2,
    "color": 0.345,
    "background": 1,
    "glitter": 0.99,
    "type": 0.1847
  },
  "attributes": [
    {
      "trait_type": "Type",
      "value": "Unisheep"
    },
    {
      "trait_type": "Horn",
      "value": "Spiral Horn"
    },
    {
      "trait_type": "Color",
      "value": "Green"
    },
    {
      "trait_type": "Background",
      "value": "Mountain Range"
    },
    {
      "trait_type": "Opening Network",
      "value": "Binance Smart Chain"
    },
    {
      "trait_type": "Glitter",
      "value": "No"
    },
    {
      "trait_type": "Special",
      "value": "No"
    },
    {
      "display_type": "date",
      "trait_type": "Birthday",
      "value": 1628902374
    },
    {
      "display_type": "number",
      "trait_type": "Booster",
      "value": 10000000195586
    }
  ],
  "opening_network": "Binance Smart Chain",
  "background_color": "FFFFFF",
  "animation_url": "https://assets.polkamon.com/videos/Unimons_T08C02H06B04G00.mp4",
  ...
}

Read Contract>