CBDE BTA Certified Blockchain Developer - Ethereum Questions and Answers

everybody can become a miner, everybody can send transactions and everything is public.

usually only a few selected nodes can be miners. Transactions can be further limited.

it would be best to start from scratch, just looking at the required interface.

it is beneficial to copy and paste the already existing code from the Ethereum wiki and modify this until you like it.

best is to start with an audited implementation, for example from OpenZeppelin, in order to reuse already existing code.

can only be accessed during calls.

can be accessed during transactions and calls.

ERC are here to define standards for the usage of Ethereum. EIP are here to improve the Ethereum Protocol itself.

ERC are here to propose new distributed applications on top of the Ethereum layer, while EIP are here to improve existing mining software.

ERC are an open platform to discuss continuous forking of the Ethereum platform. Successful forks are then incorporated in the EIP for further voting by the Ethereum Consortium.

contract MyContractA is MyContractB { … }

contract MyContractA inherit (MyContractB) {…}

contract MyContractA extends MyContractB {…}

contract MyContractB derives MyContractA {…}

it’s good to start with a local in-memory blockchain with unit tests but then deploy to the mainnet as rapidly as possible.

it's good to start with a local in-memory blockchain with unit-tests. Then, in the next step, debug and test the smart contract on a test-net like Ropsten or Rinkeby with beta customers to iron out last issues before deploying it to the main-net.

it's good to start with a test-net with beta-customers like on the Rinkeby or Ropsten testnet, before testing it locally on an in-memory blockchain simulation such as Ganache. Then deploy it to the main-net.

all gas is consumed

all remaining gas is returned.

are changing their address every time a Transaction is sent because of the nonce.

are keeping their address, but on the blockchain a nonce is increased every time they send a transaction to avoid replay attacks.

is much better than Solidity and a viable alternative.

can be split across multiple files, but every contract must be in a file with the same name as the contract itself.

is another language similar to LLL, more secure than Solidity.

it’s good to use a push over a pull method.

it’s good to use a push and a pull method to ensure that participants can get their money no matter the contract state. In addition to and pushing it should contain a withdraw method.

it's good to use only pull and no push method.

the amount of gas your contract deployment and transactions, against your contract, will need. This way you can essentially lower the gas costs over traditional web3.js dApps.

different Networks to deploy your contracts to. This way you can easily deploy to a local blockchain, the main-net or the Ropsten/Rinkeby Test-Net with only one parameter.

you can manage your secret API keys to the Ethereum Network. This way you can get access to several different Ethereum nodes at the same time without the need to switch your keyfiles.

To Protect the Public Keys by being cryptographically significant.

To Sign Transactions And To Derive an Address From.

To Generate An Address which can sign transactions.