On Blockchain

General

• Blockchain
  • a distributed database that maintains a continuously-growing list of records called blocks.
• A Next-Generation Smart Contract and Decentralized Application Platform
• How Bitcoin Works Under the Hood (July 14, 2013)
• Bynance Academy
  • Learn blockchain and cryptocurrency on your schedule and completely free.
• The Words of Crypto (Glossary)

• Private blockchain
• On Public and Private Blockchains (August 7th, 2015)

• What are the best open source projects to study blockchain technology in terms of simplicity?
• What is the best programming language to learn if you want to work on the blockchain?

• Bitcoin mining the hard way: the algorithms, protocols, and bytes
• A 101 Noob Intro to Programming Smart Contracts on Ethereum (Oct 29, 2015)
• Blockchain as a Database (July 31, 2015)
• Cryptocurrency tumbler
  • a service offered to mix potentially identifiable or 'tainted' cryptocurrency funds with others, so as to obscure the trail back to the fund's original source.

• State of the ÐApps
• Blockchain Use Case Failure: 43 Projects and Zero Impact (December 10, 2018)
• Blockchain Events and Conferences

• Cryptocurrency standards
• Mnemonic Code Converter
• BIP32 Deterministic Key Generator

Consensus Algorithm

• Consensus
• Liveness
• Safety
• CAP Theorem

Style	Description	Remarks
PoW	Deters denial of service attacks and other service abuses such as spam on a network by requiring some work from the service requester, usually meaning processing time by a computer.
PoS
DPoS
PoS
PoH

PoW

• Proof-of-Work, Explained (JAN 17, 2018)
• Re: Bitcoin P2P e-cash paper (Satoshi Nakamoto Thu, 13 Nov 2008)
  • The proof-of-work chain is a solution to the Byzantine Generals' Problem. I'll try to rephrase it in that context.
• Hashcash
  • a proof-of-work system used to limit email spam and denial-of-service attacks
• A partial hash collision based postage scheme (1997, Adam Back)
• Reusable Proofs of Work (RPoW) (2007, Hal Finney)
• Ethash : PoW algorithm for Ethereum 1.0
• Hashimoto: I/O bound proof of work

• On Settlement Finality (May 9, 2016)

BFT (Byzantine Fault Tolerance)

• Byzantine fault
• The Byzantine Generals Problem
• The Byzantine Generals Problem (1982, paper by LESLIE LAMPORT, ROBERT SHOSTAK, and MARSHALL PEASE)
• Reaching Agreement in the Presence of Faults
• Reaching Agreement in the Presence of Faults (1980, paper by M. PEASE, R, SHOSTAK, AND L. LAMPORT)
• The Weak Byzantine Generals Problem
• Byzantine Agreement
  • OM(m) is impractical since the message complexity is O(n^m) for n nodes.
  • SM(m) has message complexity 𝑂(𝑛²), but each node needs to send and verify O(n) signatures for every request
• Byzantine Fault Tolerance: The Key for Blockchains (JUN 29, 2017)

pBFT

• Practical Byzantine Fault Tolerance (1999, paper by Miguel Castro and Barbara Liskov)
• pBFT— Understanding the Consensus Algorithm (Nov 19, 2018)
  • Total message count per client request : 1 + 3f + 3f(3f-f) + (3f-f+1)(3f+1) + 3f-1
• Consensus Series: PBFT (Nov 7, 2019)
• Implementing PBFT in Blockchain (Aug 5, 2019)

ZKP

• Demonstrate how Zero-Knowledge Proofs work without using maths (2017.9.13)

misc

• Paxos : a family of protocols for solving consensus in a network of unreliable processors

• Tendermint: Consensus without Mining (2014)
• IBFT(Istanbul Byzantine Fault Tolerance)
• Clique PoA protocol
• The Raft Consensus Algorithm

• State machine replication
• Lower Bounds for Asynchronous Consensus (2004, paper by Leslie Lamport)

Fault Type	Cryptography	Replica Requirement
Non Byzantine Failures	Non Cryptographic	2F + 1
Non-malicious Byzantine Failures	Non Cryptographic	2F + 1
Malicious Byzantine Failures	Non Cryptographic	3F + 1
Malicious Byzantine Failures	Cryptographic	2F + 1

• ETC 51 % attack – what happened and how it was stopped (14 Jan 2019)
• Bitcoin Gold Blockchain Hit by 51% Attack Leading to $70K Double Spend (JAN 27, 2020)

• Nothing At Stake Problem – A Forkin’ Mess! (July 27, 2018)
• Understanding Proof of Stake: The Nothing at Stake Theory (Jun 8, 2018)
• What exactly is the Nothing-At-Stake problem? (Mar 29 '16)

Blockchain Networks

Network	Symbol	Consensus Style	Description	Remarks
BitCoin	BTC	PoW
Ethereum	ETH	PoW
EOS	EOS	DPoS

Blockchain Platforms

• Polkadot and Cosmos
• Polkadot vs Cosmos

Smart Contract

• Smart Contract (on Wikipedia)

Blockchain	Language	Remark
Ethereum	Solidity
EOSIO		C++

Key and Wallet

• Cryptocurrency wallet
• Deterministic Wallets, Their Advantages and their Understated Flaws (November 26, 2013, Vitalik Buterin)

• Shamir's Secret Sharing
  • a form of secret sharing, where a secret is divided into parts, giving each participant its own unique part.

• Cryptography behind the top 100 cryptocurrencies

Blockchain	Signing Algorithm	Curve	Remark
Bitcoin	ECDSA	secp256k1
Ethereum	ECDSA	secp256k1
Ripple	EdDSA, ECDSA	curve25519, secp256k1
Polkadot	EdDSA, ECDSA, Schnorr	curve25519, secp256k1, ristretto25519
Stellar	EdDSA	curve25519
EOS	ECDSA	secp256k1
Cosmos	ECDSA	secp256k1
Solana	EdDSA	curve25519

• Curve25519
  • an elliptic curve used in elliptic-curve cryptography (ECC) offering 128 bits of security (256-bit key size) and designed for use with the elliptic curve Diffie–Hellman (ECDH) key agreement scheme.

Cryptocurrency

• CoinMarketCap

• >> On Finance

Automata Theory

Theory	Description	Remarks
Finite State Machine	an abstract machine that can be in exactly one of a finite number of states at any given time.	State Machine
Turing Machine	a mathematical model of computation describing an abstract machine that manipulates symbols on a strip of tape according to a table of rules.
Turing Completeness	a system of data-manipulation rules that can be used to simulate any Turing machine.	Virtually all programming languages today are Turing-complete

Glossary

• The Words of Crypto (Binance Academy)
• Crypto Token Supply: What’s the Difference Between Maximum, Circulating and Total Supply?

Term	Description	Remarks
Total Supply	the number of coins or tokens that currently exists and are either in circulation or locked somehow.
Circulating Supply	the number of cryptocurrency coins or tokens that are publicly available and circulating in the market.
Maximum Supply	the maximum number of coins or tokens that will be ever created.	Supply Cap
Supply Cap	a permanent limit on the number of units of a cryptocurrency (or coins) that can ever be created	alias : Max Supply

Misc

• Digital wallet
• Understanding Digital Wallets (8/25/2017)
• Apple Pay security and privacy overview (October 18, 2019)
• What is a Secure Element? (April 18, 2018)
• Mobile Payment Systems: How Android Pay Works (August 01, 2015)

Performance

• The Blockchain Scalability Problem & the Race for Visa-Like Transaction Speed (Jan 31, 2019)
• FastFabric: Scaling Hyperledger Fabric to 20,000 Transactions per Second (4 Mar 2019)

Bitcoin

• Bitcoin Developer Guide
• Mastering Bitcoin (O'reilly, Andreas M. Antonopoulos)
• Bitcoin Wiki

• Best Bitcoin Mining Software (November 12, 2021)
  • CGMiner, BFGMiner, MultiMiner

• What are transaction fees and why do I need to pay them?
  • In the case of Bitcoin transactions, the reward for miners consists of two things: all transaction fees in the block that the miner validated and the additional incentive of a specific block reward of newly minted coins in the process.
  • Reward = Incentive + Fee
• What is inflation?
  • But because the amount of new bitcoin is automatically reduced by 50 percent every four years, Bitcoin’s inflation rate will also decrease.
• Controlled supply

Concepts

• Proof of work
• The Proof-of-Work Concept (June 24, 2013)
• Bitcoin mining the hard way: the algorithms, protocols, and bytes

• Orphan Block (Dec 19, 2019)
• How Bitcoin Fees Work
  • Transaction fees are based on the data volume of a transaction and the congestion of the network.

BIP

• BIPs (Bitcoin Improvement Proposals)

BIP	Title	Description	Type	Status	Remarks	Related
BIP-32	Hierarchical Deterministic Wallets	Describes hierarchical deterministic wallets (or "HD Wallets")	Informational	Final
BIP-39	Mnemonic code for generating deterministic keys	Describes the implementation of a mnemonic code or mnemonic sentence -- a group of easy to remember words -- for the generation of deterministic wallets.	Standards Track	Proposed
BIP-43	Purpose Field for Deterministic Wallets	Introduces a "Purpose Field" for use in deterministic wallets based on algorithm described in BIP-0032	Informational	Draft	m/purpose'/*	BIP 32
BIP-44	Multi-Account Hierarchy for Deterministic Wallets	Defines a logical hierarchy for deterministic wallets based on an algorithm described in BIP-0032	Standards Track	Proposed	m/44'/*'/*'/*/*	BIP 32, BIP 43, SLIP-0044

SLIP

• SLIP (SatoshiLabs Improvement Proposals)
  • an extension to BIP process containing documents unsuitable for submission to BIP repository.

HD Wallet

• Mnemonic Code Converter
• So you want to build an Ethereum HD wallet? (Mar 15, 2018)
• How to Avoid Invalid Mnemonic Phrase Error While Importing with Mnemonic Phrase (Sep '19)

Format	Purpose	Description	Remarks
m/0'/*	Default Account
m/44'/coin_type'/*'/*/*	Multi-Account		m/44'/0': BTC, m/44'/60': ETH, m/44'/61': ETC

BIP 32

• BIP 32

private parent key → private child key	: possible
public parent key → public child key	: possible
private parent key → public child key	: possible
public parent key → private child key	: impossible

• Each leaf node in the tree corresponds to an actual key, while the internal nodes correspond to the collections of keys that descend from them.
• The chain codes of the leaf nodes are ignored, and only their embedded private or public key is relevant.
• Knowing an extended private key allows reconstruction of all descendant private keys and public keys.
• Knowing an extended public keys allows reconstruction of all descendant non-hardened public keys.

$c$	256 bit entropy
$k$	private key
$K = point(k)$	public key
$(k, c)$	extended private key
$(K, c)$	extended public key
$CKD_{priv}((k_{par}, c_{par}), i) \to (k_i, c_i)$	private child key derivation(CKD) function	$0 \leqslant i \leqslant 2^{32-1}$
$CKD_{pub}((K_{par}, c_{par}), i) \to (K_i, c_i)$	public child key derivation(CKD) function	$0 \leqslant i \leqslant 2^{32-1}$
$N((k, c)) \to (K, c)$	computes extended public key
$N(CKD_{priv}((k_{par}, c_{par}), i)) = N(k_i, c_i) = (K_i, c_i)$		$0 \leqslant i \leqslant 2^{32-1}$
$CKD_{pub}(N(k_{par}, c_{par}), i) = CKD_{pub}((K_{par}, c_{par}), i) = (K_i, c_i)$	$N \cdot CKD_{priv} = CKD_{pub} \cdot N$	$0 \leqslant i \leqslant 2^{31-1}$
$CKD_{priv}(CKD_{priv}(CKD_{priv}(m, a), b), c) = m/a/b/c$	private key node	m : master extended private key
$CKD_{pub}(CKD_{pub}(CKD_{pub}(M, a), b), c) = M/a/b/c$	public key node	M : master extended public key
$N(m/a/b/c) = N(m/a/b)/c = N(m/a)/b/c = N(m)/a/b/c = M/a/b/c$		$0 \leqslant a, b, c \leqslant 2^{31-1}$

Serialization Format

Position	Value	Remarks
4 bytes	version bytes	mainnet/public: 0x0488B21E mainnet/private: 0x0488ADE4 testnet/public: 0x043587CF testnet/private: 0x04358394
1 bytes	depth	master node: 0x00 level-1 derived: 0x01
4 bytes	the fingerprint of the parent's key	master key: 0x00000000
4 bytes	child number
32 bytes	chain code	256 bit
33 bytes	the public key or private key data

Statistics

Topic	Chart/Table	Remarks	Avg. Block Time	https://bitinfocharts.com/comparison/bitcoin-confirmationtime.html

• BTC.com / Bitcoin Explorer
• Bitcoin (BTC) price stats and information
• Bitcoin Explorer
• Bitnodes : estimate the size of the Bitcoin network by finding all the reachable nodes in the network

Ethereum

• >> On Ethereum

Substrate

• https://github.com/paritytech/substrate
• Desc. : a next-generation framework for blockchain innovation

• What is Substrate? (July 09, 2018)

Ripple

• https://ripple.com/
• Desc. : a network of computers which use the Ripple consensus algorithm to atomically settle and record transactions on a secure distributed database
• License : ISC license
• Written in : C++
• Sources : https://github.com/ripple
• RPM packages :
  • https://mirrors.ripple.com/rpm/
  • https://mirrors.ripple.com/rpm/el7/stable/x86_64/

• WebSocket API Tool
• Data API v2 Tool

References

• Ripple Developer Center
• Ripple Wiki
• Ripple Concepts
• rippled API Reference
• RippleAPI Reference : the official client library to the XRP Ledger
• Ripple Data API : provides access to information about changes in the XRP Ledger, including transaction history and processed analytical data
• rippled-example.cfg

• RocksDB option file example

rippled API

Category	API	Methods	Description	Remarks
Public	subscribe	WebSocket	requests periodic notifications from the server when certain events happen	Ledger Stream, Validations Stream, Transaction Streams, Peer Status Stream, Order Book Streams
Admin	ledger_request	WebSocket, Commandline	tells server to fetch a specific ledger version from its connected peers

Consensus

• Consensus and Validation

   Round Start --------------- Close -------------------- Consensus -------------------- Round End
                 Open phase            Establish phase                  Accept phase

• The XRP Ledger Consensus Process
• Consensus
  • Concensus
    • Through the consensus process, validating nodes agree on a specific subset of the candidate transactions to be considered for the next ledger
    • Consensus is an iterative process in which nodes relay proposals, or sets of candidate transactions.
    • Nodes communicate and update proposals until a supermajority 5 of peers agree on the same set of candidate transactions.
  • Validation
    • The validating nodes calculate a new version of the ledger and relay their results to the network, each sending a signed hash of the ledger it calculated based on the candidate transactions proposed during consensus.
    • In cases where a node is in the minority, having computed a ledger that differs from its peers, the node disregards the ledger it computed 9. It recomputes the correct ledger, or retrieves the correct ledger as needed.
• rippled Server States

                                                            +--> full
                                                            |
   disconnected ---> connected ---> syncing ---> tracking --| 
                                                            |
                                                            +--> validating <-----> proposing

Transaction

• Reliable Transaction Submission
  • Best Practices
  • Your rippled server should automatically acquire the missing ledger versions when it has spare resources (CPU/RAM/disk IO) to do so, unless the ledgers are older than its configured amount of history to store. Depending on the size of the gap and the resource usage of your server, acquiring missing ledgers should take a few minutes. You can also manually request your server to acquire historical ledger versions using the ledger_request method.
  • Use the LastLedgerSequence parameter to prevent undesirable cases where a transaction is not confirmed promptly but could be included in a future ledger. You should specify the LastLedgerSequence parameter on every transaction. Automated processes should use a value of 4 greater than the last validated ledger index to make sure that a transaction is validated or rejected in a predictable and prompt way.

• Transaction submission and verification programming guideline

• Transaction Common Fields
• Transaction Results

Ledger

• Ledgers
  • Ledger = Header + Transaction Tree + State Tree (Ledger Objects)
  • At any given time, a rippled instance has an in-progress "current" open ledger, plus some number of closed ledgers that have not yet been approved by consensus, and any number of historical ledgers that have been validated by consensus.
  • Only the validated ledgers are certain to be correct and immutable.

• Ledger Data Formats
  • boolean ledger.closed
  • boolean ledger.accepted

• Ledger Header
  • Two ledgers with the same hash are always the same.
  • For validated ledgers, hash values and sequence numbers are equally valid and correlate 1:1.
  • Two different rippled servers may have different contents for a current ledger with the same ledger index, due to latency in propagating transactions throughout the network.
  • There may be multiple closed ledger versions competing to be validated by consensus. These ledger versions have the same sequence number but different contents (and different hashes). Only one of these closed ledgers can become validated.
  • A current ledger's contents change over time, which would cause its hash to change, even though its ledger index number stays the same. The hash of a ledger is not calculated until the ledger is closed.

Amendments

• Amendments
• Known Amendments

Readings

• Install rippled
• Forbidden from rippled while using auth credentials (12 Oct 2018)

Troubleshooting

• Understanding Log Messages
• Diagnosing Problems with rippled

Sources

Component	Type	Description	Remarks
SHAMapStoreImp.h, SHAMapStoreImp.cpp	class
Setup	struct		deleteInterval, advisoryDelete, ledgerHistory, databasePath, deleteBatch, backOff, ageThreshold
Config.h	class

Stellar

• https://www.stellar.org/
• Desc. : Stellar is a platform that connects banks, payments systems, and people. Integrate to move money quickly, reliably, and at almost no cost.
• License :
• Sources : https://github.com/stellar

• Stellar on Wikipedia

Solana

• https://solana.com/
• Desc. :

• Solana official documentation
• Solana Cookbook
• Solana Developer Wiki
• Development Tools
• Solana Configuration Fields
  • json_rpc_url, websocket_url, keypair_path, address_labels, commitment

• Message Flow
• Turbine Block Propagation

• Solana Test Validator

A Solana cluster is capable of subsecond confirmation for up to 150 nodes with plans to scale up to hundreds of thousands of nodes. Once fully implemented, confirmation times are expected to increase only with the logarithm of the number of validators, where the logarithm's base is very high.

A Solana cluster uses a multi-layer block propagation mechanism called Turbine to broadcast transaction shreds to all nodes with minimal amount of duplicate messages.

CLI

• Solana Command-line Guide

$ solana --help

$ solana <command> --help

Command	Description	Remarks
solana config get	Get current config settings
solana config set	Set a config setting
solana config set --url url		solana config set --url http://127.0.0.1:8899
solana cluster-version	Get the version of the cluster entrypoint

Transaction

Field	Description	Remarks
signatures	List of signatures.
accounts	List of accounts (read-only / read-write)
recentBlockhash	Blockhash of recently produced block used as nonce.
instructions	List of instructions which each call an on-chain program.

• Major differences between Ethereum and Solana transactions

Smart Contract

• Developing with Rust
• Developing with C/C++

JSON RPC API

• Desc. : Interact with Solana nodes directly with the JSON RPC API via the HTTP and Websocket methods.

Explore the API

• JSON RPC HTTP Methods
• JSON RPC Websocket API

JavaScript API

• Solana-Web3.js GitHub

• Solana-Web3.js
• Solana-Web3.js API Reference
• Solana-Web3.js TypeScript API Reference

Rust API

• Rust API

Readings

• How to Build & Deploy a Solana Smart Contract using Anchor
  • Installing Rust, Installing Solana, Installing Anchor
• Deploying Solidity Smart Contracts to Solana

---

Anchor

• https://github.com/coral-xyz/anchor
• Desc. : a framework for Solana's Sealevel runtime providing several convenient developer tools for writing smart contracts.
• License : Apache-2.0 license
• Sources : https://github.com/coral-xyz/anchor

Readings

• Anchor documentation
• Anchor Book
• Anchor.toml Reference

• Anchor: A Powerful Framework for Solana Developers

Hyperledger

• Hyperledger Projects
  • Hyperledger Cello
  • Hyperledger Fabric
  • Hyperledger Iroha
  • Hyperledger Sawtooth Lake

• Blockchain Automation Framework
  • Blockchain Automation Framework Documentation

Hyperledger Fabric

• https://github.com/hyperledger/fabric
• Desc. : an implementation of blockchain technology, leveraging familiar and proven technologies.
• License : Apache License Version 2.0
• Written in : Go
• Docker repository : https://hub.docker.com/u/hyperledger/
• Docker images : https://github.com/hyperledger/fabric/tree/master/images

• Projects
  • hyperledger/fabric
  • hyperledger/fabric-docs
  • hyperledger/fabric-samples
  • hyperledger/fabric-chaincode-java
  • hyperledger/fabric-chaincode-node
  • hyperledger/fabric-chaintool
  • hyperledger/fabric-sdk-rest
  • hyperledger/fabric-sdk-node
  • hyperledger/fabric-sdk-java
  • hyperledger/fabric-sdk-py
  • hyperledger/fabric-sdk-go

Readings

• References
  • Official documentation
  • Transaction Flow
  • Read-Write set semantics
  • Bringing up a Kafka-based Ordering Service
  • CLI
  • Specification
  • REST API

• Concepts
  • Channels
    • Channel = Organizations + Ordering Service + Anchor Peers + Chaincodes + Ledger
    • At least one anchor peer per organization

• Setup
  • Getting Setup
  • Setting Up a Network
  • Multichannel Setup
  • Install and Instantiate
  • v1.0.0-alpha2
    • sample configtx.yaml
    • sample core.yaml
    • sample orderer.yaml
    • Getting Started
  • v1.0.0-beta
    • sample crypto-config.yaml

• Ordering
  • A Kafka-based Ordering Service for Fabric

• Ledger
  • Hyperledger Fabric V1.0: Block Structure (Part 1)

• Chaincode
  • What is chaincode?
  • Chaincode API
  • Java chaincode
  • Writing, Building, and Running Chaincode in a Development Environment
  • Chaincode examples
  • Where is Hyperledger fabric chaincode store location? (Jan 26)

• SDK
  • Hyperledger Fabric SDK Design Specification v1.0

• misc
  • Hyperledger Fabric Approaches v1.0 with Better Scalability and Security
  • Logging Control
  • Hyperledger Fabric V1.0: Block Structure (Part 1)

Examples

• CLI based End-to-End Flow
  • 1 Orderer, 3 Peer, 1 CLI
  • configtx.yaml
  • docker-compose.yaml
  • docker-compose-no-tls.yaml
  • script.sh : called by yaml file

• Fabric official samples
  • Build Your First Network (BYFN)

• github.com/ksachdeva/hyperledger-fabric-example
  • ksachdeva.github.io

Demos

• ITPeople Blockchain - Art Auction Demo
• IBM Blockchain - Marbles Demo

Sources

• fabric/core/ledger/util/couchdb/couchdb.go
  • 1.0.0-alpha
    • handleRequest(method, connectURL string, data io.Reader, rev string, multipartBoundary string) (*http.Response, *DBReturn, error)
  • 1.0.0-beta
    • handleRequest(method, connectURL string, data []byte, rev string, multipartBoundary string, maxRetries int, keepConnectionOpen bool) (*http.Response, *DBReturn, error)

• fabric/core/chaincode/shim/interfaces.go
  • 1.0.0-alpha
    • PutState(key string, value []byte) error
    • GetState(key string) ([]byte, error)

• fabric/core/ledger/ledgerconfig/ledger_config.go
  • 1.0.1

Issues

• FAB-6092 : Gossip error: PKIID wasn't found (10/Sep/17)
• FAB-6421 : Performance and scale improvements for 1.1 (03/Oct/17)

Docker Images

fabric-peer

Config which is printed by "docker inspect --format='{{json .Config}}' ..." is

   
 "Config": {
   "Hostname": "e7eddde82bec",
   "Domainname": "",
   "User": "",
   "AttachStdin": false,
   "AttachStdout": false,
   "AttachStderr": false,
   "Tty": false,
   "OpenStdin": false,
   "StdinOnce": false,
   "Env": [
     "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
     "PEER_CFG_PATH=/etc/hyperledger/fabric",
     "CORE_PEER_MSPCONFIGPATH=/etc/hyperledger/fabric/msp/sampleconfig"
   ],
   "Cmd": [
     "peer",
     "node",
     "start"
   ],
   "ArgsEscaped": true,
   "Image": "sha256:793719e9dd193f580f32c5984ac47a8c0f986819e4795c039703b26bb6ad15ce",
   "Volumes": null,
   "WorkingDir": "",
   "Entrypoint": null,
   "OnBuild": [],
   "Labels": {
     "org.hyperledger.fabric.base.version": "0.3.0",
     "org.hyperledger.fabric.version": "1.0.0-alpha"
   }
 },

Fabric CA

• Fabric CA User’s Guide
• Fabric CA Server REST API

Fabric SDK for Node.js

• Sources :
  • https://github.com/hyperledger/fabric-sdk-node
  • https://github.com/hyperledger/fabric-sdk-node/tree/master/fabric-client
  • https://github.com/hyperledger/fabric-sdk-node/tree/master/fabric-ca-client
• Features
  • create channels
  • ask peer nodes to join the channel
  • install chaincodes in peers
  • instantiate chaincodes in a channel
  • invoke transactions by calling the chaincode
  • query the ledger for transactions or blocks

• Readings
  • Official documentation
  • Application developer documentations

• Examples
  • Balance transfer example
    • https://github.com/hyperledger/fabric-sdk-node/tree/master/examples/balance-transfer

Performance Tuning

• JBOD or RAID

• LVM (Logical Volume Manager)

• Filesystem Journaling
  • Disabling Journaling in Ubuntu 14.04?

• ulimit, open files
  • Set ulimit parameters on ubuntu (2009/06/04)
  • Raising the Maximum Number of File Descriptors (Open Files) on Ubuntu 14.04 Trusty (2015/05/18)

• noatime
  • Reducing Disk IO By Mounting Partitions With noatime
  • Is it worth to tune Ext4 with noatime? (Aug 12 '10)
  • RHEL 6 Filesystem Mount Options

• vm.swappiness
  • Swappiness
  • RHEL 6 Tuning Virtual Memory
    • A low swappiness value is recommended for database workloads.
  • Swap Space and Kernel Swappiness
  • How do I configure swappiness? (Ask Ubuntu)

• Disk I/O Scheduler
  • Noop for SSD
  • Linux I/O Scheduler Comparison On The Linux 3.4 Desktop(11 May 2012)
  • Selecting a Linux I/O Scheduler
  • Linux Change The I/O Scheduler For A Hard Disk
  • SSD benchmark of I/O schedulers (April 28th, 2010)

• Docker OverlayFS storage driver
  • Use the OverlayFS storage driver

• CouchDB
  • Linux tuning for better CouchDB performance

• misc
  • Tuning Linux for Database performance

Companions

PTE

• https://github.com/dongmingh/v1performance
• Desc. : Performance Traffic Engine

R3 Corda

• https://www.corda.net/
• Desc. : The open source blockchain for business
• License : Apache License, Version 2.0
• Written in : Kotlin
• Sources : https://github.com/corda/corda

Concepts

• Key Concepts

Concept	Description	Remarks
State Object	a digital document which records the existence, content and current state of an agreement between two or more parties
Ledger	a set of immutable state objects
Consensus	pure function whose responsibility is either to accept or reject a proposed transaction and which can be composed from simpler, reusable functions
Transaction	Consume existing state objects and produce new state objects	Transaction Validity, Transaction Uniqueness
Smart Contract
Uniqueness and Timestamping Services
Flow Framework

          State Object ----+----> Contract Code
                           +----> Legal Prose

Features

• All communication between nodes is direct, with TLS-encrypted messages sent over AMQP/1.0
  • AMQP(Advanced Message Queuing Protocol)

References

• Corda 3.2 Documentation
• Start Coding Corda

• Setup and run cordapp-example project
• The example CorDapp (https://github.com/corda/cordapp-example)

• The Corda Platform: An Introduction (May, 2018)
• Technical White Paper (Version 0.5, November 29, 2016)

• End-State Principles

Principle	Description	Remarks
Inclusion	Parties are able to discover each other freely, and transact directly, in a single, open network
Assured identity	Parties will have assurance over the identity of participants in the network
Privacy	The only parties who have access to the details of a transaction are those who participate in the transaction and those who need to assure themselves of transaction provenance.
Shared logic	The behavior of agreements managed by the system will be described in computer code that is shared to ensure onsistency and validity of agreements
Legal footing	Deals recorded by the ledger are, by contract, accepted as admissible evidence and legally binding by all parties in any dispute
Authoritative	Facts recorded by the ledger are regarded as authoritative rather than “shadows” of authoritative data held elsewhere
Immutability	Facts recorded on the ledger are final and immutable; errors and unwinds must be processed through a subsequent transaction
Open	The system is open: open source, participation, development, governance and standards to ensure the platform balances the needs of its diverse user-base in a transparent fashion

• Intel SGX (Software Guard Extensions)

Readings

• Building Blocks of the State Machine Approach to Consensus (Jun 20, 2016)
• Closed Seal Sets and Truth Lists for Better Privacy and Censorship Resistance (Jun 22, 2016)

Terra

• https://www.terra.money/
• Desc. :
• Sources : https://github.com/terra-project

• Announcing TerraUSD (UST)— the Interchain Stablecoin (Sep 22, 2020)

Eris

• https://monax.io/
• Desc. : an open platform for developers and devops to build, ship, and run blockchain-based applications for business ecosystems.
• License : https://monax.io/library/#licensing
• Sources : https://github.com/eris-ltd

References

• Eris official documentation
• Eris Getting Started
  • Building Your First Blockchain App with Eris (August 24, 2016)
• Eris Command Line Interface
• Eris DB Web APIs
• Jobs Specification
• Variables Specification

Readings

• Using Docker Machine With Eris
• On Eris and Tendermint: Application and Consensus (2016/03/02)
• Cannot deploy smart contract with Eris / Monax
  • Could not perform pkg action service: Could not perform pkg action: Docker: {"mssage":"Cannot link to a non running container: /simplechain
• The Blockchain Explained to Web Developers, Part 1: The Theory (2016/04/28)
• The Blockchain Explained to Web Developers, Part 2: In Practice (2016/05/20)
• The Blockchain Explained to Web Developers, Part 3: The Truth (2016/06/14)
• Eris and Ethereum - Decentralized computing on a blockchain (May 20, 2015)

Tendermint Core

• https://tendermint.com/
• Desc. : Byzantine fault-tolerant replicated state machines in any programming language
• License : Apache-2.0
• Written in : Go
• Sources : https://github.com/tendermint/tendermint

Readings

• Documentation
• The latest gossip on BFT consensus (paper, September 24, 2018)

• Resources
• Consensus Protocols: Tendermint and pBFT (21 JULY 2018)
• Tendermint Explained — Bringing BFT-based PoS to the Public Blockchain Domain (May 11, 2018)
• What is the difference between PBFT, Tendermint, SBFT and HotStuff ? (June 23, 2019)

IPFS

• https://ipfs.io/
• Desc. : A peer-to-peer hypermedia protocol to make the web faster, safer, and more open

• IPFS concepts
• IPFS how-tos and tutorials
• IPFS Gateway
• IPFS Specifications
• IPFS API & CLI reference
  • Path Gateway Specification
  • Trustless Gateway Specification
  • Subdomain Gateway Specification

Type	API	Description	Remarks
Path Gateway	GET /ipfs/{cid}[/{path}][?{params}]
Subdomain Gateway	GET /[{path}][?{params}]

• Address IPFS on the Web
• An Introduction to IPFS (SEPTEMBER 17, 2020)
• Awesome IPFS

• Content Addressing on the Decentralized Web
• Anatomy of a CID

Version	Feature	Format	Description	Remarks
CIDv0	multihash		TLV(Type-Length-Value) pattern, Base58
CIDv1	multicodec, multihash	<multicodec><multihash-algorithm><multihash-length><multihash-hash>

• Merkle DAGs: Structuring Data for the Distributed Web

• IPFS Pinning Services
  • Filebase, Kaleido, Infura, Pinata]

IPFS Client

Category	Library	Description	Documentation	Remarks
Go	Go Embedded Client(go-ipfs-api)	The go interface to ipfs's HTTP API	go-ipfs-api API
	Go HTTP Client(go-ipfs-http-api)	IPFS CoreAPI implementation using HTTP API]	go-ipfs-http-api API	experimental
JavaScript	JS-IPFS HTTP Client	The JavaScript HTTP RPC API client library for IPFS implementations.
Java	Java IPFS HTTP Client(java-ipfs-http-client)	A Java client for the IPFS http api

• Managing storage in a Java application with IPFS (2019-08-14)

IPFS Gateway

• IPFS Gateway List
• Public IPFS Gateways List
• IPFS HTTP Gateways ranked by performance
• Comparing IPFS Pinning Services Pricing/Functionality. Temporal, Eternum & Pinata (Nov 11, 2019)

Provider	Service	Description	Documentation	Remarks
Cloudflare	Cloudflare IPFS Gateway	Cloudflare's read-only Distributed Web Gateway lets you access content stored on the IPFS quickly and easily, without downloading any special software or giving up any storage space on your computer.	IPFS Gateway
Pinata	Pinata Dedicated Gateways	Get even faster speed with your own IPFS dedicated server.		$20/Month

Sample Resources

Title	Format	Category	URI	Remarks
'Impression, Sunrise'	JPEG	Image	ipfs://Qmaa4Lv37rBqZU6Kes6EkddHjnm333FtLrfByodyow5wZo
Metadata for 'Impression, Sunrise'	JSON	NFT Token Meta	ipfs://QmZnYQBBk4SDQohfamMeoiquT3p7HuJ9GoFLbVbodDJ6GP
'The Starry Night'		Image	ipfs://QmPUxNiwMR3etcisHkcm2k1hYfTVJtS9w4uMFsNmtRcqAi
Metadata for 'The Starry Night'	JSON	NFT Token Meta	ipfs://QmYmEyspK37Q1eJvMo17eovzpWxZ53LDVRJGFmuSPcNaVd

NFT

• OpenSea (NFT Marketplace)
• NonFungible : The world's largest NFT data resource

• List of most expensive non-fungible tokens
• List of most expensive paintings

• NFTs, explained (Mar 11, 2021)
• Everydays: The First 5000 Days - Will Gompertz reviews Beeple's digital work
• Beeple sold an NFT for $69 million (Mar 11, 2021)

Assets

Asset	Creator	Description	Contract	Marketplace	Highest Price	Remark
EVERYDAYS: THE FIRST 5000 DAYS	Beeple		MKT2 Token	MakersPlace	$69M ('21.3.11)	Digital Artwork (JPG, 21,069 x 21,069)
Stay Free	Edward Snowden		FNDNFT Token	Foundation	2,224.00 ETH ('21.4.16)	Digital Artwork (PNG, IPFS)
x*y=k	pplpleasr		FNDNFT Token	Foundation		Digital Artwork (MP4)
Doge	Atsuko Sato	The original image that started it all	ZORA	Zora		Digital Photo

Asset	Etherscan	OpenSea	Remarks
Stay Free	0x3B3ee1931Dc30C1957379FAc9aba94D1C48a5405?a=24437	0x3b3ee1931dc30c1957379fac9aba94d1c48a5405/24437
x*y=k	0x3B3ee1931Dc30C1957379FAc9aba94D1C48a5405?a=13623	0x3b3ee1931dc30c1957379fac9aba94d1c48a5405/13623
Doge	0xabEFBc9fD2F806065b4f3C237d4b59D9A97Bcac7?a=3366	0xabefbc9fd2f806065b4f3c237d4b59d9a97bcac7/3366

Contracts

Player	Description	Contract Source	Contract Address	Documentation	Remarks
CryptoPunks	10,000 unique collectible characters with proof of ownership stored on the Ethereum blockchain.	CryptoPunksMarket.sol	CryptoPunksMarket
Rarible		MintableToken (May-27-2020)
SuperRare	Collect SuperRare Digital Artworks	SuperRareV2 (Sep-05-2019)
Nifty Gateway	the premier marketplace for Nifties, which are digital items you can truly own.
Decentraland	a decentralized virtual reality platform powered by the Ethereum blockchain.	Land Contracts Marketplace Contracts Collection Contracts	LANDProxy LANDRegistry EstateProxy EstateRegistry MarketplaceProxy Marketplace MANAToken	Decentraland documentation

Rariable Contracts

• Rarible ERC721 Contract on Etherscan
• Rarible ERC1155 Contract on Etherscan

Marketplaces

Marketplace	Service Type	Contents Type	Collections	Networks	Sources	API	Remarks
OpenSea	Open Marketplace		CryptoPunks, The Sandbox, Decentraland. SuperRare, Rarible, PolygonPunks, KlayFox	Ethereum, Polygon, Klaytn			OpenSea Explorer
Rarible	Open Marketplace		parallel, The Sandbox, Rarible, Decentraland				Rarible Top Collections
Nifty Gateway	Curated Marketplace	Digital Art		Ethereum		Nifty Gateway Public API
SuperRare	Curated Marketplace	Digital Art		Ethereum
Foundation	Curated Marketplace	Digital Art		Ethereum
NBA Top Shot	Curated Marketplace	Sports		Flow (PoS)
Axie Infinity	Curated Marketplace	Game		Ethereum
Decentraland	Curated Marketplace	Metaverse		Ethereum
The Sandbox	Curated Marketplace	Metaverse		Ethereum

• 10 Top NFT Marketplaces (Nov 2, 2021)
  • OpenSea, Axie Infinity, CryptoPunks, NBA Top Shot, Rarible, SuperRare, Foundation, Nifty Gateway, Mintable, Theta Drop
• Top 10 NFT Marketplaces
  • Open Marketpalces : OpenSea, Rarible,
  • Curated Marketpalce : Foundation, SuperRare, Nifty Gateway,
  • Collectibles Marketplace : CryptoPunks, NBA Top Shot, Ether Cards
  • Games Marketplaces : Axie Infinity, Decentraland,
• What is the biggest NFT marketplace? A top 10 comparison (Oct 29th, 2021)
  • OpenSea, Axie Infinity, NBA Top Shot, Rarible, SuperRare, Sorare, Foundation, Aavegotchi, Decentraland, Hic et Nunc
• The 8 Best NFT Marketplaces to Explore Right Now (September 21, 2021)
  • OpenSea, SuperRare, Foundation, Rarible, NiftyGateway, KnownOrigin, AsyncArt, Hic Et Nunc

• Whitelabel NFT Marketplace Development - All You Need To Know About This Innovative Platform (04 September 2021)

• Media format/size support

Marketplace	Supported Type	Max Size	Remarks
OpenSea	JPG, PNG, GIF, SVG, MP4, WEBM, WAV, OGG, GLTF, GLB	100MB
Rarible	JPG, PNG, GIF, WEBP, MP4, MP3	30MB
Foundation	JPG, GIF, SVG, PNG, MP4, GLTF	50MB

Decentraland

The finite, traversable, 3D virtual space within Decentraland is called LAND, a non-fungible digital asset maintained in an Ethereum smart contract. Land is divided into parcels that are identified by cartesian coordinates (x,y). These parcels are permanently owned by members of the community and are purchased using MANA, Decentraland’s cryptocurrency token. This gives users full control over the environments and applications that they create, which can range from anything like static 3D scenes to more interactive applications or games.

Some parcels are further organized into themed communities, or Districts. By organizing parcels into Districts, the community can create shared spaces with common interests and uses. You can find a list of the original District Proposals on GitHub. The content that makes up Decentraland is stored and distributed via a decentralized network while ownership and transactions are validated on the Ethereum blockchain.

Decentraland is partnering with Matic to create a sidechain (a special kind of blockchain) that will be able to handle transactions faster and cheaper than the main Ethereum network. This sidechain will be ideal for in-game transactions, as changes can occur closer to real time and at a very low cost. For transactions that involve valuable items, we’ll still recommend the main Ethereum chain, as it will be more secure.

• Class diagrams for Decentraland contracts for lands and wearables
• Decentraland Contract Addresses

• Decentraland shows the potential of blockchain and VR combined (December 15, 2017)

Cryptovoxels

• Cryptovoxels Wiki

• Cryptovoxels Tools & Resources

Tool	Description	Remarks
Cryptovoxel Generator	Chrome app to help easily manage your land parcels.
Cryptovoxels land sales map	Highlights all parcels for sale, plotted on the map.
MagicaVoxel	A free lightweight GPU-based voxel art editor and interactive path tracing renderer.
Babylon.js	a powerful, beautiful, simple, and open game and rendering engine packed into a friendly JavaScript framework.

• Smart Contracts

Contract	Description	Source	Address	Remarks
Parcel		Parcel.sol	0x79986af15539de2db9a5086382daeda917a9cf0c(Jun-05-2018)
Wearables			0xa58b5224e2fd94020cb2837231b2b0e4247301a6(Oct-29-2019)

Axie Infinity

• Ronin Ethereum Sidechain
• Smart contracts and GitHub Repo

STO

• Category: Security Token Offerings (STO’s)
• 4 Tokenized security platforms to watch: Polymath, Ravencoin, Neufund and Cybermiles (Jul 31, 2018)

• ERC 1400: Security Token Standard

• Polymath
• CyberMiles

• Regulation of virtual asset trading platforms (Hongkong Securities and Futures Commission)

• What are Financial Securities? Examples, Types, Regulation, and Importance (June 11, 2022)
• Offer and acceptance
• ABA routing transit number
• Routing number (ABA)
• Routing Number vs. Account Number: What's the Difference? (Jun 25, 2019)
• Securities Act of 1933

KYC/AML

• KYC: 3 Steps to Know Your Customer (MARCH 20, 2019)
• Anti-Money Laundering/Combating the Financing of Terrorism (AML/CFT) (IMF)

• What is a Proof of Address and how can you get one?
• What is a Proof of Residence?
• Top 10 KYC & AML Service Providers (Aug 17, 2018)

Polymath

• https://polymath.network/
• Desc. : enables trillions of dollars of securities to migrate to the blockchain.

• Security Token Standard

CoFi OS

• https://github.com/ConsenSys/ERC1400
• Desc. : an advanced institutional technology platform for issuing and exchanging tokenized financial assets, powered by the Ethereum blockchain.

Polymesh

• https://polymesh.network/
• Desc. : an institutional-grade permissioned blockchain built specifically for regulated assets.

• Why security tokens?

De-Fi

• DeFi Pulse : a site where you can find the latest analytics and rankings of DeFi protocols.

Service	Chain	Sector	Description	Remarks
Maker	Ethereum	Lending
Uniswap	Ethereum	DEXes
Aave	Multichain	Lending
Curve	Ethereum	DEXes
Compound	Ethereum	Lending

• DeFi Deep Dive – What is Aave? (Aug 03, 2020)
• DeFi Deep Dive – What is Curve Finance? (Jul 23, 2020)
• DeFi Deep Dive – What Is Yield Farming? (Aug 11, 2020)

• What is Yield Farming? Beginner's Guide (Nov 23, 2020)
  • At its core, yield farming is a process that allows cryptocurrency holders to lock up their holdings, which in turn provides them with rewards.

MakerDAO

• Sources
  • https://github.com/makerdao/dss : Dai Stablecoin System - the core smart contract code for Multi Collateral Dai

• The Dai Stablecoin System Whitepaper
• MakerDAO Official Documentation
• DAI 1.0 Developer Documentation

• Maker DAO / Ethereum Smart Contracts Engineer

DAI

• DAI
  • Decentralized Stable Coin
  • Backed by Ether

• DAI Purple Paper

• Dai
  • First, Dai can be used as a stable coin
  • The second use of Dai is margin trading
• Dai (DAI)
• What is Dai and how does it work? (May 9, 2019)

Compound

• Sources
  • https://github.com/compound-finance/compound-protocol : The Compound Protocol is an Ethereum smart contract for supplying or borrowing assets.

• Compound Getting Started
• cTokens Introduction
• Comptroller Introduction

• Creating a RESTful API for Compound Finance Smart Contracts (August 16, 2020)

Synthetix

• Desc: a crypto-backed synthetic asset platform.
• Sources : https://github.com/Synthetixio/synthetix

Mirror Protocol

• https://mirror.finance/
• Desc. : Allows the creation of fungible assets, “synthetics”, that track the price of real world assets.
• Sources : https://github.com/Mirror-Protocol

• Mirror Whitepaper

Synthetic tokens are tokens that provide "synthetic" exposure to the physical or abstract good that they represent without requiring one-to-one backing.

Synthetic tokens tend to be more affordable to hold as they typically charge no holding fee.

Mirror is a protocol that allows anyone to issue and trade synthetic assets that track the price of real world assets.

Anyone can mint an mAsset by locking up collateral, either in the form of as stablecoin or a different mAsset.

The Mirror protocol creates incentives for minters to mint assets and provide liquidity for traders.

The Mirror protocol utilizes AMMs to facilitate mAsset, trading against stablecoins.

When the collateral ratio drops below the minimum, the Mirror protocol needs a way to retrieve and burn the respective mAssets. It does so by seizing a portion of the collateral and initiating an auction at a discount for anyone willing to sell the mAsset in exchange.

Resource/Tool	Description	Remarks
Mirror Whitepaper
Mirror Documentation
Mirror Smart Contract	implementing Mirror Protocol on the Terra blockchain	Mint, Factory, Gov
Mirror.js	a client SDK for building applications that can interact with Mirror Protocol from within JavaScript runtimes
mirrorcli	Command-line interface for Mirror Protocol on Terra
Mirror API	an GraphQL-based data service that allows anybody to query data regarding the current and aggregate application state of the Mirror Protocol

• Collateralized Debt Position

Anchor Protocol

• https://anchorprotocol.com/
• Desc. : a savings protocol offering low-volatile yields on Terra stablecoin deposits.
• Sources : https://github.com/Anchor-Protocol

The Anchor rate is powered by a diversified stream of staking rewards from major proof-of-stake blockchains, and therefore can be expected to be much more stable than money market interest rates.

The Anchor protocol defines a money market between a lender, looking to earn stable yields on their stablecoins, and a borrower, looking to borrow stablecoins on stakeable assets.

Resource/Tool	Description	Remarks
Anchor Documentation
Anchor Money Market Contracts	implementing Anchor Protocol on the Terra blockchain.	Rust
Anchor Bonded Asset Contracts	implementing bAsset(Bonded Asset) Protocol on the Terra blockchain.
Anchor.js	a client SDK for building applications that can interact with Anchor Protocol from within JavaScript runtimes

• Money Market

DID

• A Primer for Decentralized Identifiers
• Verifiable Credentials Data Model 1.1

Concept	Description	Remarks
Holder	A role an entity might perform by possessing one or more verifiable credentials and generating verifiable presentations from them.	students, employees, customers
Issuer	A role an entity performs by asserting claims about one or more subjects, creating a verifiable credential from these claims, and transmitting the verifiable credential to a holder.	corporations, trade associations, governments
Verifier	A role an entity performs by receiving one or more verifiable credentials, optionally inside a verifiable presentation, for processing.
Subject	An entity about which claims are made. In many cases the holder of a verifiable credential is the subject, but in certain cases it is not.	human beings, animals, things
Claim	An assertion made about a subject.
Credential	A set of one or more claims made by an issuer.
Verifiable Credential	a tamper-evident credential that has authorship that can be cryptographically verified.	VC

Verifiable Credential = Credential Metadata, { Claim }, { Proof }

Verifiable Presentation = Presentation Metadata, { Verifiable Credential }, { Proof }

• Walkthrough of Decentralized Identity (DID) Network (2019-12-24)

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CBDC

• UK central bank digital currency (BoE)

Metaverse

• What is Metaverse in The Context of Cryptocurrency (March 31, 2021)