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Contract Cops
  • Mastering Ethereum Book
    • What is ethereum?
    • Tokens
    • Oracles
    • Decenralized Applications(DApps)
    • The Ethereum virtual machine
    • Ethereum basics
    • Ethereum clients
    • Cryptography
    • Wallets
    • Transactions
    • Chapter 7 - Smart Contracts & Solidity
    • Side Notes
      • Tokens
      • Smart Contracts and Solidity
  • Cryptography
    • Ethereum Cryptography - Cheatsheet
    • Assymetric vs symmetric cryptography
    • ECDSA vs RSA
    • Elliptic curves and ECDSA
    • Sha-256 Example
    • Sha-256
    • What are the different steps in SHA-256?
  • Ethereum Blocks
    • Block Headers
  • Learning Solidity
    • Storage vs memory
    • Upgradeable contracts
      • Proxy pattern in smart contracts
  • PoS
    • Proof of stake
  • PoW
    • PoW
  • Tokens
    • ERC-1155
    • ERC20
  • Cryptonomics
    • Automated market makers
    • Collateral Tokens
    • Collateralized Stablecoin
    • Fiat currency
    • Liquidity pool
    • Open Position: Meaning and Risk in Trading
    • Slippage
    • Spot price
  • Common Attack Vectors
    • Checking access control
    • Access control issues on critical functions
    • Account Existence Check for low level calls
    • Account Existence Check
    • Common attacks with contract/EOA addresses
    • Arithmetic under/overflow
    • Assert Attack
    • Assert require revert
    • Assert Violation
    • Bad Interface DOS
    • Bad pragma and compiler
    • Block Timestamp Manipulation
    • Bypassing contract check
    • Code With No Effects
    • Code size check vulnerability
    • Constructors with Care
    • Default Visibilities
    • Delegatecall
    • Delegatecall
    • Denial of Service (DoS)
    • DoS with block gas limit
    • Entropy Illusion
    • External contract referencing
    • Flash Loan Attack
    • Floating Point and Precision
    • Function selector abuse
    • Function selector abuse
    • Smart contract gas griefing
    • Hash collision parameters
    • Hash Collisions With Multiple Variable Length Arguments
    • Imprecise arithmetic
    • Improper Array Deletion
    • Incorrect array deletion
    • Incorrect interface
    • Insufficient Gas Griefing
    • Loop through long arrays
    • Message call with hardcoded gas amount
    • Not enough gas for ether transfer
    • Precision Loss in Calculations
    • Oracle Manipulation
    • Public Burn Function
    • Read-only reentrancy
    • Race Conditions/Front Running
    • Reentrancy Attacks
    • Reentrancy
    • Requirement Violation
    • Right-To-Left-Override control character (U+202E)
    • Shadowing State Variables
    • Short Address / Parameter attack
    • Signature Malleability
    • Signature Replay
    • Transaction Order Dependence
    • Tx.Origin Authentication
    • Unchecked CALL Return Values
    • Unexpected ether
    • Uninitialized Storage Pointers
    • Unsafe Ownership Transfer
  • EIP's
    • EIP155
    • EIP55
  • PoW
    • Ethash
    • Scrypt - RFC 7914
  • Questions for self evaluation
    • Questions 23/04/2023 (Nr: 84)
    • Usability guide for questions
  • Frequently asked questions
    • What is the difference between transaction and message?
    • What is the use of a interface or function without implementation?
  • UsefulResources
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  1. Mastering Ethereum Book

What is ethereum?

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Last updated 2 years ago

Ethereum is a deterministic, but unbounded state machine that consists of a global singleton state and a virual machine that applies changes to that state.

Ethereum uses ether as the currency for transactions and execution costs.

Key components of a blockchain:

P2P Network that connects participants and execute transactions and blocks of verified transactions.

This is based on a standard "gossip protocol"

Messages (Transactions) that represent state changes

Chain of blocks (hence the name blockchain) that are connected to eachother. Each block keeps the previous's block 's hash, hence why they are connected in a chain-like matter. It also serves as a journal for all of the transactions that have happened.

Consensus algorithm that decentralizes the control by making sure the participants cooperate with the consensus rules

Incentive: proof-of-work costs & block rewards. This funds the ecosystem and makes sure that the state machine can be used in an open environment.

How does Ethereum deal with DoS attacks and overuse of resources?

Ethereum has a metering resources, namely gas. As the EVM of Ethereum executes a smart contract, it calculates the costs of each instruction

When a transaction triggers the execution of a smart contract, it must include the upper limit of what that smart contract may consume in resources.

Gas can only be bought with ether and is only used for transactions. Anything thats left after a transaction is returned to the user

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