Final - Blockchain

Merkle Tree

A binary hash tree that allows efficient and secure verification of data in blockchains.

Merkle Root

The topmost hash in a Merkle Tree representing all transactions in a block.

Full Nodes

Nodes storing the entire blockchain for transaction validation.

Light Nodes

Nodes storing only block headers, using Merkle proofs for verification.

Merkle Proof

Proof that a transaction exists in a block using sibling hashes up to the root.

Elliptic Curve Cryptography (ECC)

Cryptography using elliptic curves offering strong security with smaller key sizes.

ECC Key Generation

Private key d; public key Q = dG, where G is a base point on the elliptic curve.

ECC Encryption

Encrypt message M as point Pm; ciphertext is (kG, Pm + kQ).

ECC Decryption

Use private key d to compute kQ from kG, then recover Pm = C2 - kQ.

Elliptic Curve Diffie-Hellman

A method of key exchange using elliptic curve arithmetic.

Message to Point Mapping

Hash message to x, solve y^2 = x^3 + ax + b mod p to get (x,y) on the curve.

Ethereum

A decentralized computing platform enabling smart contract execution.

Smart Contract

Self-executing code on a blockchain that enforces rules without intermediaries.

Ethereum Virtual Machine (EVM)

A virtual environment for executing smart contract bytecode.

Turing Complete

A language that can implement any algorithm, supporting loops and branching.

Etherscan

A blockchain explorer for viewing Ethereum transactions and contracts.

MetaMask

A browser extension enabling users to interact with Ethereum via wallet and dApp interface.

Transaction (Ethereum)

A signed message to transfer ETH or trigger contract execution.

Proof-of-Stake (PoS)

A consensus mechanism where validators stake ETH to propose and validate blocks.

Gas

A fee mechanism for Ethereum transactions, determined by gas limit and price.

Validator

An entity that proposes and attests blocks in PoS Ethereum by staking ETH.

Externally Owned Account (EOA)

An Ethereum account controlled by a private key, able to initiate transactions.

Contract Account

An account with smart contract code, controlled by logic, not a private key.

receive() Function

Solidity function to accept ether into a contract.

msg.sender

The sender address of the transaction invoking a contract.

transfer()

Solidity function to send ether from contract to an address.

Full Node

Stores the entire blockchain and verifies transactions and blocks.

Remote Client

Lightweight client that accesses Ethereum via RPC without storing the full chain.

Public Key

Derived from a private key; used to verify signatures and derive Ethereum addresses.

Private Key

Secret key used to sign transactions and control Ethereum accounts.

Transaction Structure

Includes nonce, gas price, gas limit, to/from addresses, and cryptographic signature.

Initial Coin Offering (ICO)

A fundraising method where tokens are sold to investors in exchange for capital.

Token

A digital asset on a blockchain representing value, resource, or access rights.

Hard Fork

A blockchain protocol change causing a split into separate chains if not all nodes upgrade.

Soft Fork

A backward-compatible protocol update that does not split the chain.

DAO (Decentralized Autonomous Organization)

An organization run by rules encoded as smart contracts without centralized control.

Hash Function

A one-way function used in cryptography to map data to a fixed-size output.

Double SHA-256

Hashing a message twice with SHA-256, often used in Bitcoin.

Digital Signature

Cryptographic proof that a message originates from a specific private key.

Base Point (G)

A publicly known point on the elliptic curve used for key generation.

Order of a Point

The smallest positive integer n such that nG = O (the point at infinity).

Point at Infinity (O)

The identity element in elliptic curve point addition.

Elliptic Curve Equation

y^2 = x^3 + ax + b mod p, defines points on the elliptic curve.

kG

The result of scalar multiplication of point G with integer k on the curve.

Ether

The native cryptocurrency of the Ethereum network, used to pay for computation.

DApp

A decentralized application that runs on a blockchain network.

Solidity

A high-level programming language for writing smart contracts on Ethereum.

Bytecode

Compiled low-level code executed by the Ethereum Virtual Machine.

State Transition

A change in blockchain state triggered by transaction execution.

Gas Limit

The maximum amount of gas units a transaction can consume.

Nonce

A transaction counter used to prevent replay attacks.

Web3.js

A JavaScript library used to interact with the Ethereum blockchain.

Sepolia

An Ethereum test network used for testing contracts with fake ETH.

Infura

A service providing Ethereum nodes and infrastructure for apps.

Alchemy

A platform offering Ethereum APIs and tools for blockchain development.

Mnemonic

A sequence of words representing a wallet's private key.

Gas Price

The amount of ETH paid per gas unit, affecting transaction speed.

EVM (Ethereum Virtual Machine)

A runtime environment for executing smart contracts.

Remix IDE

A browser-based Solidity development environment for writing and deploying contracts.

Solidity Compiler

Converts Solidity code into EVM bytecode.

Deployed Contract Address

The unique Ethereum address of a deployed smart contract.

msg.value

Amount of Ether (in wei) sent with a transaction to a contract.

require()

A Solidity function that checks conditions and reverts if false.

Geth

The Go language implementation of the Ethereum client.

Parity

A former Rust-based Ethereum client, known for speed and modularity.

LevelDB

A fast key-value storage library used for Ethereum state storage.

Merkle Patricia Tree

A data structure used to store Ethereum’s state.

Wallet

A software tool for managing Ethereum addresses and signing transactions.

Hardware Wallet

A physical device for securely storing private keys offline.

DAO

A Decentralized Autonomous Organization governed by smart contracts.

Ethereum Classic

A continuation of the original Ethereum blockchain after the DAO fork.

White Paper

A document outlining a project's purpose, technology, and tokenomics.

Utility Token

A token used to access a service or product in a blockchain ecosystem.

Equity Token

A token representing ownership or voting rights in a DAO or company.

Voting Token

Used to cast votes in blockchain-based governance systems.

Fork

A change in blockchain protocol that can split the chain (hard/soft fork).

SegWit

A Bitcoin soft fork that separates signature data to allow more transactions per block.

Bitcoin Cash

A hard fork of Bitcoin increasing the block size limit.

Bitcoin Gold

A Bitcoin fork aimed at decentralizing mining using GPUs.

Gas Fee Formula

Total Fee = Gas Units Used × (Base Fee + Priority Fee)

Gas Fee Example

21,000 × (10 + 2) = 252,000 gwei = 0.000252 ETH

Validator Tip (Gas)

Tip = Gas Units × Priority Fee = 21,000 × 2 = 0.000042 ETH

Base Fee Burned

Burned Fee = Gas Units × Base Fee = 21,000 × 10 = 0.00021 ETH

Solidity Operation Gas

x+y = 3 gas, x-y = 3 gas, x*y = 5 gas, x>y = 3 gas → Total = 14 gas

Total Solidity Gas Cost

Total Cost = Gas × gasPrice → 14 × 5 = 70 wei

PoS Block Time

Time per slot = 12 seconds; one block proposed per slot

ECC Key Generation

Public Key Q = d × G (where d is private key and G is base point)

Elliptic Curve Equation

y² = x³ + ax + b mod p

Merkle Proof Process

Hash leaf node → Combine with sibling → Hash to parent → Repeat until root

Merkle Root Validation

If computed root == block header root → Proof is valid