Blockchain

data store

replication of data across nodes

Digital signature to authenticate

Trilemma

Decentralization

Scalability

Security

Advantages

Decentralization

immutability

Transparency

Security

Types

Public

Private

Federated

Definitions

Blockchain

System of recording data in a way that makes it difficult or impossible to change , hack or cheat the system

Blockchain mining

Process of adding records to blockchain

Distributed System

Collection of independant computers connected via a network

Hadoop

Software platform that makes it possible for users to manage huge amount of data and helps in data storage and processing

Distributed hash table

Distributed system that provides a lookup service similar to hash table key-value pairs are stored in DHT and any participating node can efficiently retrieve the value associated with a given key

Turing Complete

Any machine that given enough time and memory can solve any computational problem

Hash Function

A hash function is any function that can be used to map data of arbitrary size to fixed-size values. The values returned by a hash function are called hash values,

Merkle Tree

Data Structure that is used in Computer Science application in bicoin and other crypto, merkle tree serves to encode blockchain data more efficiently and securely. Allows to verify sepicific transaction without downloading whole blockchainH

Hard Fork

Radical change that makes all previous blocks invalid, requires all nodes to update mining software. Creates permanent divergence.

Soft Fork

A soft fork is a software upgrade that is backwards compatible with older versions. This means that participants that did not upgrade to the new software will still be able to participate in validating and verifying transactions

Nakomoto Consensus

Set of rules that verify the authenticity of a blockchain network using a combination of proof of work consensus algorithm on a BFT P2P network

Proof of work is a form of cryptographic zero-knowledge proof in which one party proves to others that a certain amount of a specific computational effort has been expended

The Proof of Stake (PoS) concept states that a person can mine or validate block transactions according to how many coins they hold. This means that the more coins owned by a miner, the more mining power they have.

Proof of burn (POB) is an alternative consensus algorithm that tries to address the high energy consumption issue of a POW system. POB is often called a POW system without energy waste. It operates on the principle of allowing miners to “burn” virtual currency tokens.

Distributed Ledger

DB that is consensually shared and synchronized acorss multiple sites accessible by multiple ppl.

Ethereum

Ethereum is a decentralized, open-source blockchain with smart contract functionality. Ether is the native cryptocurrency of the platform. After Bitcoin, it is the largest cryptocurrency by market capitalization. Ethereum is the most actively used blockchain.

BlockHeader contents

Parent hash
nonce
timestamp
logsBloom
beneficiary
gas limit
gas used
state root
txn root
receipt root
difficulty
extra data

A DAO is an organization represented by rules encoded as a computer program that is transparent, controlled by the organization members and not influenced by a central government

Smart Contract

A smart contract is a computer program which is intended to automatically execute events according to the terms of a contract

Smart Contract code needs to be

Deterministic
Terminable
Isloated

GHOST (Greedy heaviest object sub tree)

Sidechain

A sidechain is a separate blockchain which runs in parallel to Ethereum mainnet and operates independently. It has its own consensus algorithm (e.g. Proof of Authority, Delegated proof-of-stake, Byzantine fault tolerance). It is connected to mainnet by a two-way bridge

Namecoin

Namecoin is a cryptocurrency originally forked from bitcoin software. It is based on the code of bitcoin and uses the same proof-of-work algorithm. Like bitcoin, it is limited to 21 million coins. Namecoin can store data within its own blockchain transaction database.Namecoin was developed as the basis for a decentralized domain name system (DNS). DNS translates human-readable domain names (for example, www.google.com) to machine-readable IP addresses (for example, 000.0.0.00) for .bit domains