Make BlockChain

Why?

For building deep learning model with blockchain together.

What if?

Each layer with blockchain : perceptron == block and interconnection of block perceptrons

or

Each model with blockchain : model == block and interconnection of block models

On this Repository

1. Basic Blockchain Concept

2. Explorer with *.gohtml

3. REST API ~> Router of Gorilla MUX

4. Simple CLI, and It will be by cobra CLI

5. Database of bolt ~> hash(key): block(value)

   • for checking db : boltbrowser and boltdbweb

6. PoW(Proof of Work) about Mining ~> ex. verified block's first 19 digits of hash are 0

   • hard to solve but easy to verify

7. Transaction & uTxO(Unspent Transaction Outputs)

   Details

   • Tx : transaction

   • TxIn : money before transaction

   • TxOut : money after transaction

   • Mempool(Memory Pool) == Unconfirmed

   • Check whether is Unsent Transaction

   • Check whether trasaction is on Mempool

   • Refactoring

     • Method: should mutate struct ~>ex. func (b *blockchain) AddBlock()
     • if not, it is function ~> ex. func Blocks(b *blockchain) []*Block

   • Deadlock

     • Because no call to Do returns until the one call to f returns, if f causes Do to be called, it will deadlock.

8. Wallet

   Details

   • check the owner owns unspent transaction output ~> hash and signature

   • verify the owner approves the transaction

   • how signature and verification work ~> public key and private key by elliptic curve cryptography

   • persistency for wallet ~> backend for wallet

   • implement of signature and verification, applied to transaction

   • how to verify someone is unspent transaction ouput's owner ~> signature from private key and address from public key / TxIn to know unspent TxOut

   • TxIn has signature, and signature is by private key

   • TxOut has address, address is where you sent, and address is public key

   • Tx{ TxIn[ (TxOut1) (TxOut2) ], Sign } ~~~>>> TxIn.Sign + TxOut1.Address = true / false

9. P2P

   Details

   • P2P Network : Network, many nodes running same software ~> Decentralization
   • WebSocket : Notification system in real time, nodes discovering and conneting each other ~> making mesh and updating each other, broadcasting transaction to whole network
     • protocol like http, but difference is http is stateless(after send and receive request, no memory of connection between user and server ~> after request, server do not remember user)
     • websocket is alive connection(bi-directional connection) ~> alive bi-directional connection with all nodes ~> upgrade http(stateless protocol, server forger user) to websocket(statefull protocol, server remember user)
   • Channel : Connecting peers for network ~> occur race codition problem, beacuse of concurrnecy
   • Race Condition Problem ~> new version of bolt bbolt & Mutexes fix it
     • data race happens when two goRoutine access same data in an application
     • one goRoutine reads the data and the other updates the data
     • solution: locking the data ~> mutex
   • Broadcasting all information with all nodes

10. BONUS

    Details

    • Godoc
      • godoc -http=:6060
    • Testing
      • Coverage
      • Interface
      • go test ./... -v
      • go test -v -coverprofile cover.out ./...
      • go tool cover -html=cover.out or go tool cover -html="cover.out"
      • go test -v -coverprofile "cover.out" ./... && go tool cover -html="cover.out"
      • table test
      • unit test : test a code independently with other codes in the same file
      • cut the dependency on db, like os.WriteFile(), db.View(), ...