source: Mastering Ethereum, Chapter 2 by Andreas Antonopoulos

Ether

(ETH, $\Xi$) Currency unit for Ethereum

subdivided into wei. $10^{18}$wei is one ether

Wallets

software application - helps you manage your Ethereum account

  • holds your keys
  • broadcasts transactions for you

Wallets only work if they have access to your private keys, so don’t get a sketchy wallet

controlling your keys

the highest security is an air-gapped device

never store your private key in plain form (especially digitally)

use a password manager or pen and paper

Switching Networks within a Wallet

MetaMask connects to the main Ethereum network by default, but you could also connect to other networks

  • Ropsten Test Network - public testing network, ETH has no value
  • [localhost](http://localhost) 8545

The World Computer

You can think of the EVM (Ethereum Virtual Machine) as a global singleton running smart contracts on a single thread. Use Ether to pay to run smart contracts

Externally Owned Accounts (EOAs)

accounts that have a private key (as opposed to a contract account, which has an address but no private key)

Creating a Contract

you need to send the bytecode to the zero address