Blockchain CBDE BTA Certified Blockchain Developer - Ethereum Exam Practice Test

are a great way to circumvent gas requirements, because a loop will only consume gas once.

are dangerous when used with data structures that grow, such as arrays or mapping, because it is hard to estimate the gas requirements.

should be avoided where possible, because of unknown side-effects on the gas requirements.

True

False

the Keys can be anything, but the value can't be another mapping or struct.

the Value can be anything, but the key cannot be another mapping, struct, integer or Boolean.

the value can be anything, but the key cannot be another mapping, struct, enum or dynamically sized array.

would be better, because it can reduce the amount of energy needed for mining.

would be worse, because it would increase the amount of energy needed for mining.

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.

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.

Keccack256 while internally to hash values it's easy to use the Dagger-Hashimoto to create a meaningful hash.

the Dagger-Hashimoto hashing while internally the EVM uses SHA256 which is an alias for Keccack256.

the Dagger-Hashimoto hashing while internally the EVM uses Keccack256 which is almost similar to SHA256, but has a different padding so produces different hashes.

Websites that try to interface with the Token would have to know the exact ABI. It is upfront clear how the interaction has to be with the standard Interfaces.

The Ethereum Foundation can easily validate the Tokens and approve any audits by following the standard interface.

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.

for Java, JavaScript, and C++

for JavaScript using Web3.js

for Solidity and JavaScript

for any language, as long as it adheres to the open Testing-Interface from Truffle

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.

must implement the Ethereum protocol and external access can only be done via the proprietary Ethereum Libraries like Web3.js.

must implement the Ethereum Protocol and a JSON-RPC to talk with clients.

must implement Web3.js to interact with Websites.

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.

to bytecode that can't be understood by humans.

to bytecodes which are essentially opcodes running instruction by instruction.